Unit 1 Chapter 3 (1st Secondary) Biology

1. In the reaction involving the catalase enzyme and the hydrogen peroxide, the enzyme breaks the reactant into …….

H2O and O2

H+ and O2

H2O2 + H2

None of the above

The catalase enzyme catalyzes the decomposition of hydrogen peroxide (H2O2) into water (H2O) and oxygen gas (O2). This reaction occurs naturally in cells and helps to break down the toxic hydrogen peroxide into harmless water and oxygen.

Explanation

The catalase enzyme catalyzes the decomposition of hydrogen peroxide (H2O2) into water (H2O) and oxygen gas (O2). This reaction occurs naturally in cells and helps to break down the toxic hydrogen peroxide into harmless water and oxygen.

2. The graph provided shows the reaction profile of a biological reaction. Which letter indicates the activation energy?

X

Y

Z

W

The activation energy is the energy required for a reaction to occur. In the given graph, the letter X represents the highest point on the reaction profile, which indicates the activation energy. This is because the reactants need to overcome this energy barrier in order to proceed to the products.

Explanation

The activation energy is the energy required for a reaction to occur. In the given graph, the letter X represents the highest point on the reaction profile, which indicates the activation energy. This is because the reactants need to overcome this energy barrier in order to proceed to the products.

3. Enzyme catalyzing rearrangement of atomic groupings without altering molecular weight or number of atoms is ……

Ligase

Isomerase

Lipase

Pepsin

Isomerases are enzymes that catalyze the rearrangement of atomic groupings within a molecule, resulting in the formation of isomers. Isomers are molecules that have the same molecular formula but different structural arrangements. In this case, the enzyme catalyzes the rearrangement of atomic groupings without altering the molecular weight or number of atoms in the molecule. Ligase, lipase, and pepsin do not perform this specific function, making isomerase the correct answer.

Explanation

Isomerases are enzymes that catalyze the rearrangement of atomic groupings within a molecule, resulting in the formation of isomers. Isomers are molecules that have the same molecular formula but different structural arrangements. In this case, the enzyme catalyzes the rearrangement of atomic groupings without altering the molecular weight or number of atoms in the molecule. Ligase, lipase, and pepsin do not perform this specific function, making isomerase the correct answer.

4. Which of the following statements is true about metabolism?

It only involves the processes that build up the large molecules in the body.

It only involves the processes that break down the small molecules in the body.

It only involves the processes that break down the large molecules in the body.

It involves all of the processes that break down and build up molecules in the body.

Metabolism involves all of the processes that break down and build up molecules in the body. This includes both anabolic processes, which build up larger molecules from smaller ones, and catabolic processes, which break down larger molecules into smaller ones. Therefore, the statement that metabolism involves all of the processes that break down and build up molecules in the body is true.

Explanation

Metabolism involves all of the processes that break down and build up molecules in the body. This includes both anabolic processes, which build up larger molecules from smaller ones, and catabolic processes, which break down larger molecules into smaller ones. Therefore, the statement that metabolism involves all of the processes that break down and build up molecules in the body is true.

5. In some metabolic reactions, large molecules are broken down into smaller ones. What biological reaction breaks down glucose in cells to release energy?

Mitosis

Respiration

Osmosis

Photosynthesis

Respiration is the biological reaction that breaks down glucose in cells to release energy. During respiration, glucose is broken down in a series of chemical reactions, ultimately producing ATP (adenosine triphosphate), which is the main energy currency of cells. This process occurs in the mitochondria of cells and is essential for providing energy for various cellular activities. Mitosis is the process of cell division, osmosis is the movement of water across a semipermeable membrane, and photosynthesis is the process by which plants convert sunlight into energy.

Explanation

Respiration is the biological reaction that breaks down glucose in cells to release energy. During respiration, glucose is broken down in a series of chemical reactions, ultimately producing ATP (adenosine triphosphate), which is the main energy currency of cells. This process occurs in the mitochondria of cells and is essential for providing energy for various cellular activities. Mitosis is the process of cell division, osmosis is the movement of water across a semipermeable membrane, and photosynthesis is the process by which plants convert sunlight into energy.

6. In enzymatic reactions, substrates (reactants) and products have specific energies. In order to transform the reactants into products, the reactants would have to go through a transition state which is usually higher in energy (point B in the graph). To get to this transition state, the system requires activation energy. (The energy required to start a reaction) The lower the activation energy, the faster the reaction happens. The graph below illustrates an enzymatic reaction, where the activation energy of this reaction, is the difference between the two points ........

(A) and (D)

(B) and (D)

(C) and (D)

(B) and (A)

The graph illustrates an enzymatic reaction, with the transition state represented by point B. The activation energy required to reach this transition state is the difference between points B and A. Therefore, the correct answer is (B) and (A).

Explanation

The graph illustrates an enzymatic reaction, with the transition state represented by point B. The activation energy required to reach this transition state is the difference between points B and A. Therefore, the correct answer is (B) and (A).

7. Which is not true about enzymes?

Enzymes are biological catalysts.

Enzymes are proteins.

Enzymes speed up reactions by raising the activation energy required to start the reaction.

Enzymes are not changed in the reaction.

Enzymes actually lower the activation energy required to start a reaction, not raise it. This allows reactions to occur more easily and at a faster rate.

Explanation

Enzymes actually lower the activation energy required to start a reaction, not raise it. This allows reactions to occur more easily and at a faster rate.

8. "Lock and key theory" is related with …....

Digestion of carbohydrates in the intestine.

Absorption of carbohydrates from intestine.

Absorption of proteins to the blood.

Diffusion of water to inside plant cells.

The lock and key theory is related to the digestion of carbohydrates in the intestine. This theory suggests that enzymes, which act as the "keys," have specific shapes that fit into the "locks" of specific substrates. In the case of carbohydrate digestion, enzymes such as amylase break down complex carbohydrates into smaller molecules that can be absorbed and utilized by the body. This process of breaking down carbohydrates into simpler forms is essential for their digestion and absorption in the intestine.

Explanation

The lock and key theory is related to the digestion of carbohydrates in the intestine. This theory suggests that enzymes, which act as the "keys," have specific shapes that fit into the "locks" of specific substrates. In the case of carbohydrate digestion, enzymes such as amylase break down complex carbohydrates into smaller molecules that can be absorbed and utilized by the body. This process of breaking down carbohydrates into simpler forms is essential for their digestion and absorption in the intestine.

9. Which of the following statements correctly links enzymes, substrates, and active sites?

The enzyme’s active site is constantly changing to have a complementary shape to a range of substrates.

The substrate has an active site that has a complementary shape to a range of enzymes.

The substrate has an active site that has an identical shape to a specific enzyme.

The enzyme has an active site that has an identical shape to a range of substrates.

The enzyme has an active site that has a complementary shape to a specific substrate.

The correct answer is "The enzyme has an active site that has a complementary shape to a specific substrate." This statement accurately describes the relationship between enzymes, substrates, and active sites. Enzymes are proteins that catalyze chemical reactions by binding to specific substrates at their active sites. The active site of an enzyme is specifically shaped to fit and bind with a particular substrate, like a lock and key. This complementary shape allows the enzyme to interact with the substrate and facilitate the reaction.

Explanation

The correct answer is "The enzyme has an active site that has a complementary shape to a specific substrate." This statement accurately describes the relationship between enzymes, substrates, and active sites. Enzymes are proteins that catalyze chemical reactions by binding to specific substrates at their active sites. The active site of an enzyme is specifically shaped to fit and bind with a particular substrate, like a lock and key. This complementary shape allows the enzyme to interact with the substrate and facilitate the reaction.

10. In humans salivary amylase enzyme breaks down starch. What is the optimum pH for this reaction?

7.8 - 8.2

2.5 - 3

5.7 - 6

6.8 - 7.5

Salivary amylase is an enzyme that helps break down starch in the mouth. Enzymes usually have an optimum pH at which they function most effectively. In the case of salivary amylase, the optimum pH range for its activity is 6.8 - 7.5. This means that the enzyme works best and catalyzes the breakdown of starch most efficiently within this pH range. Deviations from this pH range can result in reduced enzyme activity and slower starch digestion.

Explanation

Salivary amylase is an enzyme that helps break down starch in the mouth. Enzymes usually have an optimum pH at which they function most effectively. In the case of salivary amylase, the optimum pH range for its activity is 6.8 - 7.5. This means that the enzyme works best and catalyzes the breakdown of starch most efficiently within this pH range. Deviations from this pH range can result in reduced enzyme activity and slower starch digestion.

11. In the reaction involving the catalase and the hydrogen peroxide, at the beginning time, the …..

Number of reactant break down decreases

Number of reactant break down increases

Reactants break down decreases first then increases

None of them

In the reaction involving catalase and hydrogen peroxide, the catalase enzyme helps break down the hydrogen peroxide into water and oxygen. At the beginning of the reaction, there is a high concentration of hydrogen peroxide, and as the reaction progresses, the catalase enzyme breaks down more and more hydrogen peroxide molecules. Therefore, the number of reactant break down increases over time.

Explanation

In the reaction involving catalase and hydrogen peroxide, the catalase enzyme helps break down the hydrogen peroxide into water and oxygen. At the beginning of the reaction, there is a high concentration of hydrogen peroxide, and as the reaction progresses, the catalase enzyme breaks down more and more hydrogen peroxide molecules. Therefore, the number of reactant break down increases over time.

12. At 0°C, enzyme action …… because the rate of formation of enzyme substrate complex ……... . But raising the temperature, …….. the formation rate. Therefore enzyme action ………. .

Decreases / increases / speeds up / stops.

Increases / stops / decreases / speeds up.

Speeds up / increases / stops / decreases.

Stops / decreases / speeds up / increases.

At 0°C, enzyme action stops because the rate of formation of enzyme-substrate complex decreases. But raising the temperature speeds up the formation rate. Therefore, enzyme action increases.

Explanation

At 0°C, enzyme action stops because the rate of formation of enzyme-substrate complex decreases. But raising the temperature speeds up the formation rate. Therefore, enzyme action increases.

13. What monomer subunits join together to form starch in a metabolic reaction?

Sucrose

Glucose

Glycogen

Cellulose

Glucose monomer subunits join together to form starch in a metabolic reaction. Starch is a polysaccharide that serves as a storage form of energy in plants. Glucose molecules link together through glycosidic bonds to form long chains of starch. This allows plants to store excess glucose for later use when energy is needed. Sucrose, glycogen, and cellulose are also polysaccharides, but they are not the monomer subunits that form starch.

Explanation

Glucose monomer subunits join together to form starch in a metabolic reaction. Starch is a polysaccharide that serves as a storage form of energy in plants. Glucose molecules link together through glycosidic bonds to form long chains of starch. This allows plants to store excess glucose for later use when energy is needed. Sucrose, glycogen, and cellulose are also polysaccharides, but they are not the monomer subunits that form starch.

14. Without digestive enzymes, animals would not be able to break down food molecules quickly enough to provide themselves with the energy and nutrients they need to survive. Which of the following would most likely happen in the absence of digestive enzymes in an animal's body?

The rate of digestion reactions would increase extremely.

The digestion reactions would proceed but at an extremely lower rate.

The digestion reactions would stop completely.

The rate of digestion reactions would remain the same.

Digestive enzymes play a crucial role in breaking down food molecules into smaller, absorbable units. Without these enzymes, the digestion reactions would still occur, but at a much slower pace. This is because the enzymes are responsible for speeding up the chemical reactions involved in digestion. Without them, the process would be significantly slowed down, resulting in a much lower rate of digestion reactions.

Explanation

Digestive enzymes play a crucial role in breaking down food molecules into smaller, absorbable units. Without these enzymes, the digestion reactions would still occur, but at a much slower pace. This is because the enzymes are responsible for speeding up the chemical reactions involved in digestion. Without them, the process would be significantly slowed down, resulting in a much lower rate of digestion reactions.

15. Fill in the blank: The reactant that an enzyme will bind to, due to its complementary shape, is a/an …………..

Active site

Protein

Catalyst

Substrate

Product

Enzymes are proteins that act as catalysts in biochemical reactions. They have a specific region called the active site where they bind to a molecule called the substrate. The active site and the substrate have complementary shapes, allowing them to fit together like a lock and key. This binding of the substrate to the active site facilitates the reaction, allowing the enzyme to catalyze the conversion of the substrate into a product. Therefore, the correct answer is substrate.

Explanation

Enzymes are proteins that act as catalysts in biochemical reactions. They have a specific region called the active site where they bind to a molecule called the substrate. The active site and the substrate have complementary shapes, allowing them to fit together like a lock and key. This binding of the substrate to the active site facilitates the reaction, allowing the enzyme to catalyze the conversion of the substrate into a product. Therefore, the correct answer is substrate.

16. From the experiment of the action of catalase enzyme on the hydrogen peroxide, the catalase works best at a pH of ….....

1

4

7

10

Catalase is an enzyme that helps break down hydrogen peroxide into water and oxygen. Enzymes are sensitive to changes in pH, and their activity can be affected by it. In this experiment, the catalase enzyme works best at a pH of 7. This is because pH 7 is considered neutral, and many enzymes have an optimal pH around this range. At pH 7, the enzyme's active site is in the proper conformation to bind with the hydrogen peroxide substrate and catalyze the reaction efficiently.

Explanation

Catalase is an enzyme that helps break down hydrogen peroxide into water and oxygen. Enzymes are sensitive to changes in pH, and their activity can be affected by it. In this experiment, the catalase enzyme works best at a pH of 7. This is because pH 7 is considered neutral, and many enzymes have an optimal pH around this range. At pH 7, the enzyme's active site is in the proper conformation to bind with the hydrogen peroxide substrate and catalyze the reaction efficiently.

17. The following graph shows the effect of altering a factor on the rate of an enzyme controlled reaction. What is shown on the x axis?

PH

Temperature

Substrate concentration

Enzyme concentration

The x-axis on the graph shows the factor that is being altered, and the effect of this alteration on the rate of an enzyme controlled reaction is being measured. The correct answer is "Temperature" because the graph is showing how changing the temperature affects the rate of the reaction.

Explanation

The x-axis on the graph shows the factor that is being altered, and the effect of this alteration on the rate of an enzyme controlled reaction is being measured. The correct answer is "Temperature" because the graph is showing how changing the temperature affects the rate of the reaction.

18. Which of the following reaction is catalyzed by Lipase?

Breaking of bonds

Formation of bonds

Intramolecular rearrangement of bonds

Transfer of group from one molecule to another

Lipase is an enzyme that catalyzes the hydrolysis of ester bonds in lipids, resulting in the breaking of bonds between fatty acids and glycerol. This reaction allows for the breakdown of fats and oils into smaller molecules, such as fatty acids and glycerol, which can be further metabolized by the body for energy or other purposes. Therefore, the correct answer is "Breaking of bonds".

Explanation

Lipase is an enzyme that catalyzes the hydrolysis of ester bonds in lipids, resulting in the breaking of bonds between fatty acids and glycerol. This reaction allows for the breakdown of fats and oils into smaller molecules, such as fatty acids and glycerol, which can be further metabolized by the body for energy or other purposes. Therefore, the correct answer is "Breaking of bonds".

19. Most enzymes work best at a pH of about ……..

5

6

7

8

Most enzymes work best at a pH of around 7 because this is the pH at which their active site is most stable and can effectively bind to the substrate. At higher or lower pH levels, the active site may become denatured or the charges on the enzyme and substrate may be disrupted, preventing proper binding and reducing enzyme activity. Therefore, a pH of 7 is optimal for most enzymes to function efficiently.

Explanation

Most enzymes work best at a pH of around 7 because this is the pH at which their active site is most stable and can effectively bind to the substrate. At higher or lower pH levels, the active site may become denatured or the charges on the enzyme and substrate may be disrupted, preventing proper binding and reducing enzyme activity. Therefore, a pH of 7 is optimal for most enzymes to function efficiently.

20. The following graph shows the effect of a factor on the activity of two enzymes. What should be shown on the x axis?

Temperature

PH

Substrate concentration

Enzyme concentration

The x-axis of the graph should represent the factor that is being tested, which in this case is the effect of a factor on the activity of two enzymes. The graph shows the effect of this factor on the enzymes, so the x-axis should represent the different levels or values of the factor being tested. In this case, the factor being tested is pH, so pH should be shown on the x-axis.

Explanation

The x-axis of the graph should represent the factor that is being tested, which in this case is the effect of a factor on the activity of two enzymes. The graph shows the effect of this factor on the enzymes, so the x-axis should represent the different levels or values of the factor being tested. In this case, the factor being tested is pH, so pH should be shown on the x-axis.

21. Why are amylases, proteases and lipases added to detergents? Because ....

Amylases break down starch stains / proteases break down protein stains / lipases break down fat and grease stains.

Amylases break down protein stains / proteases break down starch stains / lipases break down fat and grease stains.

Amylases break down starch stains / proteases break down fat and grease stains / lipases break down protein stains.

Amylases break down fat and grease stains / proteases break down protein stains / lipases break down starch stains.

not-available-via-ai

Explanation

not-available-via-ai

22. Amylase is an enzyme that has an optimum pH of around 6.7–7.0. Which of the graphs demonstrates how the activity of amylase varies with pH?

Graph (D)

Graph (B)

Graph (A)

Graph (C)

Graph (A) shows that the activity of amylase is highest at a pH of around 6.7-7.0, which matches the optimum pH range for amylase. The other graphs do not demonstrate this relationship between amylase activity and pH.

Explanation

Graph (A) shows that the activity of amylase is highest at a pH of around 6.7-7.0, which matches the optimum pH range for amylase. The other graphs do not demonstrate this relationship between amylase activity and pH.

23. The pancreatic juice does not contain …….

Pancreatic amylase

Lipase

Pepsin

Trypsin

The pancreatic juice is a fluid secreted by the pancreas that aids in digestion. It contains enzymes such as pancreatic amylase, lipase, and trypsin, which help break down carbohydrates, fats, and proteins respectively. However, pepsin is not found in pancreatic juice. Pepsin is an enzyme that is produced in the stomach and helps in the digestion of proteins.

Explanation

The pancreatic juice is a fluid secreted by the pancreas that aids in digestion. It contains enzymes such as pancreatic amylase, lipase, and trypsin, which help break down carbohydrates, fats, and proteins respectively. However, pepsin is not found in pancreatic juice. Pepsin is an enzyme that is produced in the stomach and helps in the digestion of proteins.

24. The enzyme differs from the chemical catalyst in that the enzyme ……….

Does not decompose in the reaction

Increases the rate of reaction

Has an organic chemical structure

Decreases heat of activation of the reaction

Enzymes are biological catalysts that are made up of organic molecules, specifically proteins. Unlike chemical catalysts, which can be inorganic compounds, enzymes have a complex organic chemical structure. This organic structure allows enzymes to interact with specific substrates and speed up chemical reactions without being consumed or decomposed in the process. Therefore, the correct answer is that enzymes have an organic chemical structure.

Explanation

Enzymes are biological catalysts that are made up of organic molecules, specifically proteins. Unlike chemical catalysts, which can be inorganic compounds, enzymes have a complex organic chemical structure. This organic structure allows enzymes to interact with specific substrates and speed up chemical reactions without being consumed or decomposed in the process. Therefore, the correct answer is that enzymes have an organic chemical structure.

25. The enzyme sticks to the …… and product is released.

Enzyme-substrate complex

Reaction

Neighboring enzyme

Substrate

The correct answer is "Substrate". In an enzymatic reaction, the enzyme binds to the substrate to form an enzyme-substrate complex. This complex allows the enzyme to catalyze the reaction and convert the substrate into a product. Once the reaction is complete, the product is released from the enzyme, allowing it to bind to another substrate molecule and continue the catalytic process. Therefore, the substrate is the molecule to which the enzyme binds and from which the product is eventually released.

Explanation

The correct answer is "Substrate". In an enzymatic reaction, the enzyme binds to the substrate to form an enzyme-substrate complex. This complex allows the enzyme to catalyze the reaction and convert the substrate into a product. Once the reaction is complete, the product is released from the enzyme, allowing it to bind to another substrate molecule and continue the catalytic process. Therefore, the substrate is the molecule to which the enzyme binds and from which the product is eventually released.

26. An experiment was carried out to know the effect of the acidity degree and the enzyme action; the results were recorded on the figure below. What are the X-axis and the Y-axis represent?

A

B

C

D

The X-axis represents the acidity degree, while the Y-axis represents the enzyme action.

Explanation

The X-axis represents the acidity degree, while the Y-axis represents the enzyme action.

27. Enzymes …..... complex molecules into simpler ones.

Build up

Break down

Accelerate

Deactivate

Enzymes are biological catalysts that speed up chemical reactions in the body. They do this by breaking down complex molecules into simpler ones. This process is known as catabolism. Therefore, the correct answer is "Break down."

Explanation

Enzymes are biological catalysts that speed up chemical reactions in the body. They do this by breaking down complex molecules into simpler ones. This process is known as catabolism. Therefore, the correct answer is "Break down."

28. Why does the rate of enzyme activity decrease as it approaches 40^O C?

The enzyme is becoming denatured.

There is more enzyme present.

There is more kinetic energy.

There are more collisions between enzyme and substrate (forming the enzyme-substrate complex.)

As the temperature approaches 40°C, the enzyme starts to denature. Denaturation is the process in which the enzyme loses its shape and function due to the disruption of its weak chemical bonds. The increase in temperature causes the enzyme's active site to change, preventing it from effectively binding with the substrate and catalyzing the reaction. Therefore, the rate of enzyme activity decreases as it approaches 40°C due to denaturation.

Explanation

As the temperature approaches 40°C, the enzyme starts to denature. Denaturation is the process in which the enzyme loses its shape and function due to the disruption of its weak chemical bonds. The increase in temperature causes the enzyme's active site to change, preventing it from effectively binding with the substrate and catalyzing the reaction. Therefore, the rate of enzyme activity decreases as it approaches 40°C due to denaturation.

29. Few enzymes …….. complex molecules from simple ones.

Build up

Break down

Inhibit the formation of

Deactivate

Enzymes are biological catalysts that speed up chemical reactions in living organisms. In this context, enzymes are responsible for building up complex molecules from simple ones. They facilitate the synthesis of larger molecules by joining smaller molecules together through chemical reactions. This process is known as anabolic reactions. Therefore, the correct answer is "Build up."

Explanation

Enzymes are biological catalysts that speed up chemical reactions in living organisms. In this context, enzymes are responsible for building up complex molecules from simple ones. They facilitate the synthesis of larger molecules by joining smaller molecules together through chemical reactions. This process is known as anabolic reactions. Therefore, the correct answer is "Build up."

30. Gluconeogenesis is a metabolic pathway that results in the formation of a 6-carbon glucose molecule from two 3-carbon non–carbohydrate molecules. Which of the following is true about gluconeogenesis?

This process requires energy.

This process involves the oxidation of a 6-carbon glucose molecule.

This process involves the hydrolysis of a 3-carbon non-carbohydrate molecule into a glucose molecule.

This process is an example of a catabolic reaction.

Gluconeogenesis is a process in which glucose is synthesized from non-carbohydrate sources. Since the formation of glucose requires energy, it is true that this process requires energy. The other statements are incorrect. Gluconeogenesis does not involve the oxidation of a 6-carbon glucose molecule or the hydrolysis of a 3-carbon non-carbohydrate molecule into a glucose molecule. Additionally, gluconeogenesis is not an example of a catabolic reaction, as it involves the synthesis of glucose rather than the breakdown of molecules.

Explanation

Gluconeogenesis is a process in which glucose is synthesized from non-carbohydrate sources. Since the formation of glucose requires energy, it is true that this process requires energy. The other statements are incorrect. Gluconeogenesis does not involve the oxidation of a 6-carbon glucose molecule or the hydrolysis of a 3-carbon non-carbohydrate molecule into a glucose molecule. Additionally, gluconeogenesis is not an example of a catabolic reaction, as it involves the synthesis of glucose rather than the breakdown of molecules.

31. Lipase is an enzyme that has an optimum pH of 8.0–9.0. Which graph shows how the activity of lipase varies with pH?

Graph (C)

Graph (B)

Graph (A)

Graph (D)

Graph (B) shows that the activity of lipase is highest at pH 8.0-9.0, which matches the optimum pH range for lipase. In this graph, the activity of lipase gradually increases as the pH increases from acidic to alkaline conditions, and then starts to decrease beyond pH 9.0. This indicates that lipase has the highest activity at pH 8.0-9.0, making Graph (B) the correct answer.

Explanation

Graph (B) shows that the activity of lipase is highest at pH 8.0-9.0, which matches the optimum pH range for lipase. In this graph, the activity of lipase gradually increases as the pH increases from acidic to alkaline conditions, and then starts to decrease beyond pH 9.0. This indicates that lipase has the highest activity at pH 8.0-9.0, making Graph (B) the correct answer.

32. The figure below illustrates the enzyme-substrate interaction. What do the labels A, B, C, and D mean?

A enzyme-substrate complex / B enzyme / C products / D substrate

A enzyme-substrate complex / B substrate / C enzyme / D products

A substrate / B enzyme / C enzyme-substrate complex / D products

A products / B substrate / C enzyme / D enzyme substrate complex

The labels A, B, C, and D in the figure represent the different components involved in the enzyme-substrate interaction. A represents the enzyme-substrate complex, where the enzyme and substrate are bound together. B represents the substrate, which is the molecule that the enzyme acts upon. C represents the enzyme, which is the protein that catalyzes the chemical reaction. D represents the products, which are the molecules formed as a result of the enzymatic reaction.

Explanation

The labels A, B, C, and D in the figure represent the different components involved in the enzyme-substrate interaction. A represents the enzyme-substrate complex, where the enzyme and substrate are bound together. B represents the substrate, which is the molecule that the enzyme acts upon. C represents the enzyme, which is the protein that catalyzes the chemical reaction. D represents the products, which are the molecules formed as a result of the enzymatic reaction.

33. In the graph shown below, what are the terms (A), (B), (C) and (D)?

(A) reactants/ (B) products/ (C) with enzyme/ (D) without enzyme

(A) products/ (B) reactants/ (C) with enzyme/ (D) without enzyme

(A) Products/ (B) reactants/ (C) without enzyme/ (D) with enzyme

(A) Reactants/ (B) products/ (C) without enzyme/ (D) with enzyme

The graph shows the relationship between reactants and products in a chemical reaction, with and without the presence of an enzyme. The x-axis represents time, while the y-axis represents the concentration of reactants and products. The correct answer is (A) Reactants/ (B) products/ (C) without enzyme/ (D) with enzyme because it accurately describes the terms represented by each letter in the graph.

Explanation

The graph shows the relationship between reactants and products in a chemical reaction, with and without the presence of an enzyme. The x-axis represents time, while the y-axis represents the concentration of reactants and products. The correct answer is (A) Reactants/ (B) products/ (C) without enzyme/ (D) with enzyme because it accurately describes the terms represented by each letter in the graph.

34. Which of the following is true about these processes?

Cellular respiration does not release energy.

Photosynthesis is a process that involves the building up of molecules.

Photosynthesis breaks down molecules into smaller ones.

Cellular respiration is an anabolic process.

Photosynthesis is a process that involves the building up of molecules. This is true because during photosynthesis, plants use sunlight to convert carbon dioxide and water into glucose and oxygen. Glucose is a molecule that stores energy, and the process of photosynthesis builds up this energy-rich molecule.

Explanation

Photosynthesis is a process that involves the building up of molecules. This is true because during photosynthesis, plants use sunlight to convert carbon dioxide and water into glucose and oxygen. Glucose is a molecule that stores energy, and the process of photosynthesis builds up this energy-rich molecule.

35. Cellulase is an enzyme that can break down cellulose, and it has an optimum temperature of around 50^∘C .Which graph best displays how the activity of cellulase changes with temperature?

Graph (A)

Graph (B)

Graph (C)

Graph (D)

Graph (A) best displays how the activity of cellulase changes with temperature because it shows a gradual increase in activity as temperature increases up to around 50∘C, which is the optimum temperature for cellulase. After reaching the optimum temperature, the activity starts to decrease. This pattern is consistent with the characteristics of enzymes, which have an optimal temperature at which they function most efficiently and their activity decreases at higher temperatures.

Explanation

Graph (A) best displays how the activity of cellulase changes with temperature because it shows a gradual increase in activity as temperature increases up to around 50∘C, which is the optimum temperature for cellulase. After reaching the optimum temperature, the activity starts to decrease. This pattern is consistent with the characteristics of enzymes, which have an optimal temperature at which they function most efficiently and their activity decreases at higher temperatures.

36. The chemical reactions in the living organisms are catalyzed by biological catalysts called ……..

Hormones

Enzymes

Carbohydrates

Lipids

Enzymes are biological catalysts that facilitate chemical reactions in living organisms. They speed up the rate of reactions by lowering the activation energy required for the reaction to occur. Enzymes are highly specific and can only catalyze a particular reaction or a group of related reactions. They are essential for various metabolic processes such as digestion, respiration, and synthesis of molecules. Hormones, carbohydrates, and lipids are important components of living organisms but do not directly catalyze chemical reactions.

Explanation

Enzymes are biological catalysts that facilitate chemical reactions in living organisms. They speed up the rate of reactions by lowering the activation energy required for the reaction to occur. Enzymes are highly specific and can only catalyze a particular reaction or a group of related reactions. They are essential for various metabolic processes such as digestion, respiration, and synthesis of molecules. Hormones, carbohydrates, and lipids are important components of living organisms but do not directly catalyze chemical reactions.

37. As the temperature increases from 0⁰C to the optimal temperature, the reacting molecules gain…….. energy and move faster.

Less

More

No

None of the above

As the temperature increases, the reacting molecules gain more energy and move faster. This is because higher temperatures provide more kinetic energy to the molecules, causing them to vibrate and move at a faster rate.

Explanation

As the temperature increases, the reacting molecules gain more energy and move faster. This is because higher temperatures provide more kinetic energy to the molecules, causing them to vibrate and move at a faster rate.

38. The enzyme in the diagram has had its active site irreversibly changed. What scientific term describes this change?

Deformation

Decomposition

Denaturation

Deposition

Denaturation is the correct term to describe the irreversible change in the active site of an enzyme. Denaturation occurs when the protein structure of the enzyme is disrupted, leading to the loss of its normal shape and function. This can be caused by factors such as high temperature, extreme pH levels, or exposure to certain chemicals.

Explanation

Denaturation is the correct term to describe the irreversible change in the active site of an enzyme. Denaturation occurs when the protein structure of the enzyme is disrupted, leading to the loss of its normal shape and function. This can be caused by factors such as high temperature, extreme pH levels, or exposure to certain chemicals.

39. Which of the following graphs represents the metabolism in a baby?

A

B

C

None

Graph B represents the metabolism in a baby. The graph shows a steady increase in metabolism over time, which is typical for a growing baby. The other graphs do not show this consistent upward trend, making them less likely to represent the metabolism in a baby.

Explanation

Graph B represents the metabolism in a baby. The graph shows a steady increase in metabolism over time, which is typical for a growing baby. The other graphs do not show this consistent upward trend, making them less likely to represent the metabolism in a baby.

40. Enzymes in general start to get damaged with a rise in temperature above …... ^OC

40

80

Zero

30

Enzymes are proteins that catalyze chemical reactions in the body. However, they are sensitive to changes in temperature. As the temperature increases, the enzymes become more and more damaged. At a certain temperature, known as the optimum temperature, enzymes function at their highest efficiency. Above this temperature, the enzymes start to denature and lose their shape, leading to a decrease in their activity. Therefore, the correct answer is 40 degrees Celsius, as it represents the temperature at which enzymes begin to get damaged.

Explanation

Enzymes are proteins that catalyze chemical reactions in the body. However, they are sensitive to changes in temperature. As the temperature increases, the enzymes become more and more damaged. At a certain temperature, known as the optimum temperature, enzymes function at their highest efficiency. Above this temperature, the enzymes start to denature and lose their shape, leading to a decrease in their activity. Therefore, the correct answer is 40 degrees Celsius, as it represents the temperature at which enzymes begin to get damaged.

41. With reference to enzymes, what does "denatured" mean?

The enzyme’s active site has been irreversibly changed.

The enzyme has been killed.

The enzyme has been used as much as it can be and must be replaced.

The enzyme has been damaged and subsequently works more slowly.

Denaturation of an enzyme refers to the irreversible alteration of its active site, which is the specific region where substrates bind and reactions occur. This change can be caused by factors such as high temperature, extreme pH, or exposure to certain chemicals. When the active site is denatured, the enzyme loses its ability to catalyze reactions effectively or at all. This is different from being killed or used up, as denaturation refers specifically to the structural change in the active site.

Explanation

Denaturation of an enzyme refers to the irreversible alteration of its active site, which is the specific region where substrates bind and reactions occur. This change can be caused by factors such as high temperature, extreme pH, or exposure to certain chemicals. When the active site is denatured, the enzyme loses its ability to catalyze reactions effectively or at all. This is different from being killed or used up, as denaturation refers specifically to the structural change in the active site.

42. The enzyme catalase catalyzes the reaction that breaks down hydrogen peroxide into water and oxygen. The graph shows how much oxygen is produced over time when this reaction occurs with and without catalase. Which of the following statements correctly describes the trend shown?

The reaction produces more oxygen when catalase is present.

The reaction produces more oxygen when catalase is not present.

The reaction produces oxygen at a quicker rate when catalase is present.

The reaction produces oxygen at a quicker rate when catalase is not present.

The graph shows that the rate of oxygen production is higher when catalase is present compared to when it is not present. This is evident from the steeper slope of the line representing the reaction with catalase. Therefore, the correct statement is that the reaction produces oxygen at a quicker rate when catalase is present.

Explanation

The graph shows that the rate of oxygen production is higher when catalase is present compared to when it is not present. This is evident from the steeper slope of the line representing the reaction with catalase. Therefore, the correct statement is that the reaction produces oxygen at a quicker rate when catalase is present.

43. The following graph shows the effect of a factor on the activity of two enzymes.What are the enzymes (X) and (Y)?

X is amylase, Y is trypsin

X is catalase, Y is pepsin

X is amylase, Y is trypsin

X is pepsin, Y is trypsin

Based on the information given in the graph, it can be concluded that the factor being tested has a greater effect on the activity of enzyme Y compared to enzyme X. Therefore, the correct answer is X is pepsin, Y is trypsin.

Explanation

Based on the information given in the graph, it can be concluded that the factor being tested has a greater effect on the activity of enzyme Y compared to enzyme X. Therefore, the correct answer is X is pepsin, Y is trypsin.

44. If in a certain enzymatic reaction, an enzyme (E) works on a substrate (S). What makes the rate of reaction constant after some time of starting the reaction?

The increase in the enzyme concentration

The increase in the substrate concentration

The saturation of the enzyme active sites in all enzyme molecules

The increase in the number of active sites

The rate of reaction becomes constant after some time of starting the reaction because the enzyme active sites become saturated. This means that all the active sites on the enzyme molecules are occupied by substrate molecules, and no more substrate molecules can bind to the enzyme. As a result, the rate of reaction reaches a maximum and remains constant as long as the concentration of substrate and enzyme remains constant. Increasing the concentration of enzyme or substrate may initially increase the rate of reaction, but once the active sites are saturated, further increases in concentration will not affect the rate.

Explanation

The rate of reaction becomes constant after some time of starting the reaction because the enzyme active sites become saturated. This means that all the active sites on the enzyme molecules are occupied by substrate molecules, and no more substrate molecules can bind to the enzyme. As a result, the rate of reaction reaches a maximum and remains constant as long as the concentration of substrate and enzyme remains constant. Increasing the concentration of enzyme or substrate may initially increase the rate of reaction, but once the active sites are saturated, further increases in concentration will not affect the rate.

45. Assuming that rolling a huge ball across a hill as in the figure below, represents a biochemical reaction that takes place without enzyme. So the energy of activation can be illustrated by ……..

(A)

(B)

(A) plus (B)

(A) minus (B)

The correct answer is (A) because the energy of activation represents the energy barrier that must be overcome for a biochemical reaction to occur. Rolling a huge ball across a hill without an enzyme represents a reaction without any assistance, so the energy of activation can be illustrated by the energy required to push the ball up the hill.

Explanation

The correct answer is (A) because the energy of activation represents the energy barrier that must be overcome for a biochemical reaction to occur. Rolling a huge ball across a hill without an enzyme represents a reaction without any assistance, so the energy of activation can be illustrated by the energy required to push the ball up the hill.

46. The reaction rate of pepsin enzyme is high at a pH of …..

5 – 6

7

8 – 9

1 – 2

The reaction rate of pepsin enzyme is high at a pH of 1-2 because pepsin is an enzyme that functions in the acidic environment of the stomach. The low pH helps to denature proteins and activate pepsin, allowing it to break down proteins into smaller peptides. Therefore, a pH of 1-2 is the optimal range for pepsin activity.

Explanation

The reaction rate of pepsin enzyme is high at a pH of 1-2 because pepsin is an enzyme that functions in the acidic environment of the stomach. The low pH helps to denature proteins and activate pepsin, allowing it to break down proteins into smaller peptides. Therefore, a pH of 1-2 is the optimal range for pepsin activity.

47. In an alkaline medium, the rate of pepsin ……..

Increases

Decreases then stop

Decreases then increases

Is not affected

In an alkaline medium, pepsin, which is an enzyme responsible for protein digestion in the stomach, becomes denatured and loses its activity. This causes the rate of pepsin to initially decrease. Eventually, the alkaline environment completely stops the activity of pepsin, leading to a complete halt in the rate of pepsin.

Explanation

In an alkaline medium, pepsin, which is an enzyme responsible for protein digestion in the stomach, becomes denatured and loses its activity. This causes the rate of pepsin to initially decrease. Eventually, the alkaline environment completely stops the activity of pepsin, leading to a complete halt in the rate of pepsin.

48. The enzyme trypsin functions best at pH of ….

2

3

7

8

not-available-via-ai

Explanation

not-available-via-ai

49. The pepsin enzyme works at a pH of 1.2 – 2.5 inside the stomach. Which one of the following graphs shows what happens to pepsin if the pH value increases inside the stomach?

A

B

C

D

The pepsin enzyme works optimally at a low pH range of 1.2 to 2.5. As the pH value increases inside the stomach, it becomes more alkaline or basic. This change in pH would lead to a decrease in the activity of pepsin, as it is most effective in an acidic environment. Therefore, graph C, which shows a decrease in pepsin activity as the pH value increases, is the correct answer.

Explanation

The pepsin enzyme works optimally at a low pH range of 1.2 to 2.5. As the pH value increases inside the stomach, it becomes more alkaline or basic. This change in pH would lead to a decrease in the activity of pepsin, as it is most effective in an acidic environment. Therefore, graph C, which shows a decrease in pepsin activity as the pH value increases, is the correct answer.

50. When you eat a large meal, the _____ activity called digestion takes the biomolecules you consumed and breaks them down into smaller molecules.

Nutrition

Anabolic

Catabolic

Respiratory

When you eat a large meal, the catabolic activity called digestion takes the biomolecules you consumed and breaks them down into smaller molecules. Catabolic refers to the process of breaking down complex molecules into simpler ones, which is exactly what happens during digestion. This process allows the body to extract and absorb nutrients from the food we eat.

Explanation

When you eat a large meal, the catabolic activity called digestion takes the biomolecules you consumed and breaks them down into smaller molecules. Catabolic refers to the process of breaking down complex molecules into simpler ones, which is exactly what happens during digestion. This process allows the body to extract and absorb nutrients from the food we eat.

51. The relationship between an enzyme and a reactant molecule can best be described as ……….

A temporary association.

An association stabilized by a covalent bond.

One in which the enzyme is changed permanently.

A permanent mutual alteration of structure.

Non-complementary binding.

Enzymes and reactant molecules form a temporary association because enzymes catalyze reactions by binding to the reactant molecules, forming an enzyme-substrate complex. This association is temporary because once the reaction is complete, the enzyme releases the product and can bind to another substrate molecule. This allows the enzyme to be reused and participate in multiple reactions.

Explanation

Enzymes and reactant molecules form a temporary association because enzymes catalyze reactions by binding to the reactant molecules, forming an enzyme-substrate complex. This association is temporary because once the reaction is complete, the enzyme releases the product and can bind to another substrate molecule. This allows the enzyme to be reused and participate in multiple reactions.

52. According to the figure below, Which of the following statements is incorrect ......

Photosynthesis process requires energy.

Oxidation of free fatty acids requires energy.

Adding an amino acid to a polypeptide chain requires energy.

All condensation reactions are anabolic.

The oxidation of free fatty acids actually releases energy, rather than requiring it. During this process, the fatty acids are broken down to produce ATP, which is a source of energy for the body. This is why the statement is incorrect.

Explanation

The oxidation of free fatty acids actually releases energy, rather than requiring it. During this process, the fatty acids are broken down to produce ATP, which is a source of energy for the body. This is why the statement is incorrect.

53. Why is a period of intense exercise often followed by heavy breathing?

To increase the temperature of the body

To increase the heart rate

To remove oxygen from the bloodstream

To provide cells with energy

To replace the oxygen lost

During intense exercise, the body requires more oxygen to meet the increased energy demands. As a result, the breathing rate increases to take in more oxygen and remove carbon dioxide. This heavy breathing is necessary to replace the oxygen that is being used up by the muscles during exercise.

Explanation

During intense exercise, the body requires more oxygen to meet the increased energy demands. As a result, the breathing rate increases to take in more oxygen and remove carbon dioxide. This heavy breathing is necessary to replace the oxygen that is being used up by the muscles during exercise.

54. Look at the following diagram, which represents the energy diagram for a chemical reaction. Which point on the diagram represents the point at which the transition state exists?

A

B

C

D

In the given energy diagram, the transition state represents the highest energy point in the reaction pathway. It is the point at which the reactants have absorbed enough energy to overcome the activation energy barrier and form the products. Looking at the diagram, point B is the highest point, indicating that it represents the transition state.

Explanation

In the given energy diagram, the transition state represents the highest energy point in the reaction pathway. It is the point at which the reactants have absorbed enough energy to overcome the activation energy barrier and form the products. Looking at the diagram, point B is the highest point, indicating that it represents the transition state.

55. Taq polymerase is an enzyme found in bacteria that live in hot springs. Its optimum temperature is 75–80∘C. Which graph best displays how the activity of Taq polymerase changes with temperature?

Graph (D)

Graph (B)

Graph (C )

Graph (A)

Graph (D) best displays how the activity of Taq polymerase changes with temperature. This is because graph (D) shows a steep increase in activity at temperatures between 75-80∘C, which is the optimum temperature for Taq polymerase. As the temperature increases beyond this range, the activity of Taq polymerase starts to decline. This pattern aligns with the enzyme's characteristics and behavior in hot springs bacteria.

Explanation

Graph (D) best displays how the activity of Taq polymerase changes with temperature. This is because graph (D) shows a steep increase in activity at temperatures between 75-80∘C, which is the optimum temperature for Taq polymerase. As the temperature increases beyond this range, the activity of Taq polymerase starts to decline. This pattern aligns with the enzyme's characteristics and behavior in hot springs bacteria.

56. The beginning of the reaction between the catalase and the hydrogen peroxide in the graph below represents …...

Low rate of reaction

High rate of reaction

End of the reaction

All of the them

The beginning of the reaction between the catalase and the hydrogen peroxide is represented by a high rate of reaction in the graph. This is indicated by a steep slope at the start of the graph, showing that the reaction is occurring rapidly. As time progresses, the rate of reaction may decrease, leading to a lower rate of reaction. Therefore, the correct answer is "High rate of reaction."

Explanation

The beginning of the reaction between the catalase and the hydrogen peroxide is represented by a high rate of reaction in the graph. This is indicated by a steep slope at the start of the graph, showing that the reaction is occurring rapidly. As time progresses, the rate of reaction may decrease, leading to a lower rate of reaction. Therefore, the correct answer is "High rate of reaction."

57. Which of the following statement is/are correct about Enzyme?

Both (i) and (ii) are correct

Both (i) and (iii) are correct

(i), (ii) and (iii) are correct

All the above are correct

All the statements (i), (ii), and (iii) are correct about Enzyme.

Explanation

All the statements (i), (ii), and (iii) are correct about Enzyme.

58. Which of the following best describes the lock and key theory of enzyme action?

The enzyme and substrate have identical shapes, like a “lock and key.”

The enzyme is the “lock” into which the substrate, or the “key,” fits.

Once the enzyme and substrate have joined, they are locked together and cannot be separated.

The substrate is the “lock” into which the enzyme, or the “key,” fits.

The lock and key theory of enzyme action suggests that the enzyme acts as a "lock" and the substrate acts as the "key." The enzyme has a specific shape that allows it to bind with a specific substrate, similar to how a key fits into a lock. Once the enzyme and substrate have joined, they form an enzyme-substrate complex and undergo a chemical reaction. This theory emphasizes the specificity of enzyme-substrate interactions, as only a specific substrate can bind to a specific enzyme due to their complementary shapes.

Explanation

The lock and key theory of enzyme action suggests that the enzyme acts as a "lock" and the substrate acts as the "key." The enzyme has a specific shape that allows it to bind with a specific substrate, similar to how a key fits into a lock. Once the enzyme and substrate have joined, they form an enzyme-substrate complex and undergo a chemical reaction. This theory emphasizes the specificity of enzyme-substrate interactions, as only a specific substrate can bind to a specific enzyme due to their complementary shapes.

59. In the reaction involving the catalase and the hydrogen peroxide, as the reaction time proceeds, the slope of the graph flattens, indicating a(an) …....

Decreased production of oxygen

Increased production of oxygen

Increased production of H+

End of the reaction

As the reaction time proceeds, the slope of the graph flattens, indicating that the rate of oxygen production is decreasing. This suggests that the catalase enzyme is becoming saturated with hydrogen peroxide and is unable to catalyze the reaction at the same rate as before. Therefore, the correct answer is decreased production of oxygen.

Explanation

As the reaction time proceeds, the slope of the graph flattens, indicating that the rate of oxygen production is decreasing. This suggests that the catalase enzyme is becoming saturated with hydrogen peroxide and is unable to catalyze the reaction at the same rate as before. Therefore, the correct answer is decreased production of oxygen.

60. Which of the statements regarding enzymes is false?

Enzymes are proteins that function as catalysts.

Enzymes are specific.

Enzymes provide activation energy for reactions.

Enzyme activity can be regulated.

Enzymes may be used many times for a specific reaction.

Enzymes are proteins that function as catalysts, meaning they speed up chemical reactions without being consumed in the process. Enzymes are specific, meaning they only catalyze specific reactions. Enzyme activity can be regulated, allowing cells to control the rate of reactions. Enzymes may be used many times for a specific reaction, as they are not consumed during the reaction. However, enzymes do not provide activation energy for reactions. Activation energy is the energy required to start a reaction, and enzymes lower the activation energy required for a reaction to occur.

Explanation

Enzymes are proteins that function as catalysts, meaning they speed up chemical reactions without being consumed in the process. Enzymes are specific, meaning they only catalyze specific reactions. Enzyme activity can be regulated, allowing cells to control the rate of reactions. Enzymes may be used many times for a specific reaction, as they are not consumed during the reaction. However, enzymes do not provide activation energy for reactions. Activation energy is the energy required to start a reaction, and enzymes lower the activation energy required for a reaction to occur.

61. Enzymes that have to be used as detergent composite must possess the following characters …..

Stability at low temperature and high pH

Stability at low temperature and low pH

Stability at high temperature and low pH

Stability at high temperature and high pH

Enzymes used as detergent composites need to be stable at high temperatures and high pH levels. This is because detergents are often used in high-temperature wash cycles and the pH of the detergent solution can be alkaline. Enzymes that are not stable under these conditions would denature and lose their activity, rendering them ineffective as detergent additives. Therefore, stability at high temperature and high pH is a crucial characteristic for enzymes used in detergents.

Explanation

Enzymes used as detergent composites need to be stable at high temperatures and high pH levels. This is because detergents are often used in high-temperature wash cycles and the pH of the detergent solution can be alkaline. Enzymes that are not stable under these conditions would denature and lose their activity, rendering them ineffective as detergent additives. Therefore, stability at high temperature and high pH is a crucial characteristic for enzymes used in detergents.

62. Which graph shows the effect of temperature on the activity of an enzyme?

A

B

C

D

Graph A shows the effect of temperature on the activity of an enzyme because it shows a gradual increase in activity as temperature increases, followed by a sharp decrease in activity at higher temperatures. This pattern is consistent with the concept of enzyme activity being influenced by temperature, where activity typically increases with temperature until it reaches an optimal temperature, after which it rapidly declines. Graphs B, C, and D do not show this pattern and therefore do not represent the effect of temperature on enzyme activity.

Explanation

Graph A shows the effect of temperature on the activity of an enzyme because it shows a gradual increase in activity as temperature increases, followed by a sharp decrease in activity at higher temperatures. This pattern is consistent with the concept of enzyme activity being influenced by temperature, where activity typically increases with temperature until it reaches an optimal temperature, after which it rapidly declines. Graphs B, C, and D do not show this pattern and therefore do not represent the effect of temperature on enzyme activity.

63. Enzymes are affected by the change in the PH value because enzymes -------.

Are protenic substances contain acidic COOH groups and basic NH2 groups

Do not contain basic NH2 groups

Do not contain acidic COOH groups

Are complex macromolecules the majority of them act in a PH of 7.4

Enzymes are complex macromolecules that function optimally at a specific pH level, typically around 7.4. Changes in pH can disrupt the structure of enzymes, altering their active sites and affecting their ability to catalyze reactions. This is because enzymes rely on specific interactions between their amino acid residues and the substrate, and pH changes can disrupt these interactions. Therefore, enzymes are affected by changes in pH, and their activity may be significantly reduced or completely inhibited outside their optimal pH range.

Explanation

Enzymes are complex macromolecules that function optimally at a specific pH level, typically around 7.4. Changes in pH can disrupt the structure of enzymes, altering their active sites and affecting their ability to catalyze reactions. This is because enzymes rely on specific interactions between their amino acid residues and the substrate, and pH changes can disrupt these interactions. Therefore, enzymes are affected by changes in pH, and their activity may be significantly reduced or completely inhibited outside their optimal pH range.

64. Which of the following best defines metabolism?

Metabolism is how quickly a person can lose weight.

Metabolism is how quickly the body digests a meal.

Metabolism is the total energy input divided by the total energy output of an organism.

Metabolism is the sum of the chemical reactions that occur in each cell of an organism.

Metabolism is the sum of all the energy lost from an organism.

Metabolism is the sum of the chemical reactions that occur in each cell of an organism. This definition encompasses the various processes that take place within cells, including the breakdown of nutrients, synthesis of molecules, and energy production. It is a fundamental aspect of living organisms and is responsible for maintaining homeostasis, growth, and reproduction. The other options provided in the question do not accurately define metabolism as they focus on specific aspects such as weight loss, digestion, or energy input/output, rather than the overall cellular processes involved.

Explanation

Metabolism is the sum of the chemical reactions that occur in each cell of an organism. This definition encompasses the various processes that take place within cells, including the breakdown of nutrients, synthesis of molecules, and energy production. It is a fundamental aspect of living organisms and is responsible for maintaining homeostasis, growth, and reproduction. The other options provided in the question do not accurately define metabolism as they focus on specific aspects such as weight loss, digestion, or energy input/output, rather than the overall cellular processes involved.

65. The graph provided shows the rate of an enzyme-controlled reaction compared to temperature. Which of the following best describes what has happened at point 2?

The elastic energy of the enzyme and substrate molecules has increased with an increase in temperature.

The concentration of the enzyme and substrates has reached its peak, and the rate of reaction has reached a plateau.

The enzyme’s optimum temperature has been reached, where the rate of reaction is at its fastest.

The enzyme has been denatured, and the reaction has stopped.

At point 2 on the graph, the rate of the enzyme-controlled reaction is at its highest. This indicates that the enzyme is functioning optimally at this temperature, resulting in the fastest rate of reaction. The other options are not supported by the information provided in the question.

Explanation

At point 2 on the graph, the rate of the enzyme-controlled reaction is at its highest. This indicates that the enzyme is functioning optimally at this temperature, resulting in the fastest rate of reaction. The other options are not supported by the information provided in the question.

66. What is the importance of catabolic processes inside the human body?

They involve providing the energy required for performing the vital activities of a cell.

They involve the synthesis of a complex molecule.

They involve storing glucose molecules as glycogen in the liver cells.

They involve forming new bonds between inorganic molecules to produce organic molecules.

Catabolic processes inside the human body are important because they provide the energy needed for the vital activities of a cell. These processes involve breaking down complex molecules into simpler ones, releasing energy in the process. This energy is then used by the cell to carry out various functions such as movement, growth, and repair. Without catabolic processes, the cell would not have the necessary energy to perform these vital activities.

Explanation

Catabolic processes inside the human body are important because they provide the energy needed for the vital activities of a cell. These processes involve breaking down complex molecules into simpler ones, releasing energy in the process. This energy is then used by the cell to carry out various functions such as movement, growth, and repair. Without catabolic processes, the cell would not have the necessary energy to perform these vital activities.

67. Why is a period of intense exercise often followed by heavy breathing?

To increase the temperature of the body

To increase the heart rate

To remove oxygen from the bloodstream

To provide cells with energy

To replace the oxygen lost

During intense exercise, the body requires more oxygen to fuel the muscles. As a result, the breathing rate increases to take in more oxygen and remove carbon dioxide, which is a waste product of cellular respiration. This heavy breathing helps to replenish the oxygen levels in the bloodstream that were depleted during exercise. By replacing the oxygen lost, the body ensures that the cells have enough oxygen to continue producing energy and function properly.

Explanation

During intense exercise, the body requires more oxygen to fuel the muscles. As a result, the breathing rate increases to take in more oxygen and remove carbon dioxide, which is a waste product of cellular respiration. This heavy breathing helps to replenish the oxygen levels in the bloodstream that were depleted during exercise. By replacing the oxygen lost, the body ensures that the cells have enough oxygen to continue producing energy and function properly.

68. In the graph shown below, what should be in the (X) axis?

PH value

Degree of temperature

Substrate concentration

Any of them

The correct answer is Substrate concentration because the graph is likely depicting the relationship between substrate concentration and another variable, such as enzyme activity or reaction rate. The X-axis typically represents the independent variable, which in this case is substrate concentration. The graph is likely showing how the dependent variable changes as the substrate concentration is varied.

Explanation

The correct answer is Substrate concentration because the graph is likely depicting the relationship between substrate concentration and another variable, such as enzyme activity or reaction rate. The X-axis typically represents the independent variable, which in this case is substrate concentration. The graph is likely showing how the dependent variable changes as the substrate concentration is varied.

69. Which of the following happens to the enzyme after the reaction is complete? (i) It is released, unchanged. (ii) It is inhibited by products. (iii) It is deactivated and recycled. (iv) It can repeat this reaction over and over, as long as substrate molecules are present.

(i) and (ii)

(ii) and (iii)

(iii) and (iv)

(i) and (iv)

After the reaction is complete, the enzyme can be released from the reaction unchanged and can repeat the same reaction over and over again as long as substrate molecules are present.

Explanation

After the reaction is complete, the enzyme can be released from the reaction unchanged and can repeat the same reaction over and over again as long as substrate molecules are present.

70. Why do we choose liver in the catalase-hydrogen peroxide experiment?

Because catalase enzyme is made from amino acids, and deamination of amino acids takes place in the liver.

Because the liver reduces the activation energy of the reaction.

Because catalase is a common enzyme found in nearly all mammals.

The liver is chosen in the catalase-hydrogen peroxide experiment because it contains the enzyme catalase, which is responsible for breaking down harmful hydrogen peroxide into water and oxygen. This enzyme helps to reduce the toxicity of hydrogen peroxide, which is a byproduct of the respiration process. The liver is a rich source of catalase and is commonly used in experiments involving this enzyme.

Explanation

The liver is chosen in the catalase-hydrogen peroxide experiment because it contains the enzyme catalase, which is responsible for breaking down harmful hydrogen peroxide into water and oxygen. This enzyme helps to reduce the toxicity of hydrogen peroxide, which is a byproduct of the respiration process. The liver is a rich source of catalase and is commonly used in experiments involving this enzyme.

71. Enzymes are characterized than other chemical catalysts in that they …….

Increase the activation energy.

Are specific for a certain substrate.

Participate in the chemical reaction.

Slow down the rate of the chemical reaction.

Enzymes are characterized by their specificity for a certain substrate, meaning that they are designed to bind and interact with a particular molecule or group of molecules. This specificity allows enzymes to catalyze specific chemical reactions, as they have a unique shape and active site that can accommodate the substrate and facilitate the reaction. Unlike other chemical catalysts, enzymes do not increase the activation energy or slow down the rate of the chemical reaction. They actively participate in the reaction by lowering the activation energy and increasing the rate of the reaction.

Explanation

Enzymes are characterized by their specificity for a certain substrate, meaning that they are designed to bind and interact with a particular molecule or group of molecules. This specificity allows enzymes to catalyze specific chemical reactions, as they have a unique shape and active site that can accommodate the substrate and facilitate the reaction. Unlike other chemical catalysts, enzymes do not increase the activation energy or slow down the rate of the chemical reaction. They actively participate in the reaction by lowering the activation energy and increasing the rate of the reaction.

72. Why is enzymatic activity affected by pH?

Because enzymes are protein substances that contain acidic carboxyl groups (COOH)

Because enzymes are protein substances that contain basic amino groups (CH3)

Because enzymes are protein substances that contain basic amino groups (COOH)

Because enzymes are protein substances that contain acidic carboxyl groups (NH2)

Enzymes are protein substances that contain acidic carboxyl groups (COOH). The pH of a solution can affect the charge of these carboxyl groups, which in turn can affect the structure and function of the enzyme. Changes in pH can disrupt the hydrogen bonding and ionic interactions within the enzyme, leading to a change in its shape and ultimately affecting its activity. Therefore, enzymatic activity is affected by pH due to the presence of acidic carboxyl groups in enzymes.

Explanation

Enzymes are protein substances that contain acidic carboxyl groups (COOH). The pH of a solution can affect the charge of these carboxyl groups, which in turn can affect the structure and function of the enzyme. Changes in pH can disrupt the hydrogen bonding and ionic interactions within the enzyme, leading to a change in its shape and ultimately affecting its activity. Therefore, enzymatic activity is affected by pH due to the presence of acidic carboxyl groups in enzymes.

73. Enzymes in the human body are adapted to work best at 37^∘C .Which graph best displays how the activity of enzymes in the body changes with temperature?

Graph (B)

Graph (A)

Graph (C)

Graph (D)

Enzymes are biological catalysts that speed up chemical reactions in the body. They have an optimal temperature at which they work most efficiently, which is typically around 37 degrees Celsius in the human body. At temperatures below the optimal range, the activity of enzymes is lower as the molecules move slower and collide less frequently, resulting in slower reaction rates. On the other hand, at temperatures above the optimal range, the activity of enzymes decreases due to denaturation, where the enzyme's structure is disrupted and it loses its catalytic function. Graph (C) would display this trend, showing a peak at 37 degrees Celsius and decreasing activity on both sides of the peak.

Explanation

Enzymes are biological catalysts that speed up chemical reactions in the body. They have an optimal temperature at which they work most efficiently, which is typically around 37 degrees Celsius in the human body. At temperatures below the optimal range, the activity of enzymes is lower as the molecules move slower and collide less frequently, resulting in slower reaction rates. On the other hand, at temperatures above the optimal range, the activity of enzymes decreases due to denaturation, where the enzyme's structure is disrupted and it loses its catalytic function. Graph (C) would display this trend, showing a peak at 37 degrees Celsius and decreasing activity on both sides of the peak.

74. Which statement BEST describes why a continued increase in pH above the optimum results in a sharp decrease in the enzyme activity as shown in the graph below?

The enzyme is denatured.

The enzyme cannot bind so well to the substrate.

Changes in pH alter the shape of an enzyme's active site.

All of them.

A continued increase in pH above the optimum can result in a sharp decrease in enzyme activity due to multiple factors. Firstly, the high pH can denature the enzyme, causing it to lose its shape and function. Additionally, changes in pH can also alter the shape of the enzyme's active site, making it less able to bind to the substrate effectively. Therefore, all of these factors contribute to the decrease in enzyme activity.

Explanation

A continued increase in pH above the optimum can result in a sharp decrease in enzyme activity due to multiple factors. Firstly, the high pH can denature the enzyme, causing it to lose its shape and function. Additionally, changes in pH can also alter the shape of the enzyme's active site, making it less able to bind to the substrate effectively. Therefore, all of these factors contribute to the decrease in enzyme activity.

75. What is the main advantage of using nanotechnology for drug delivery?

Successful delivery to the targeted region of the body

Efficient encapsulation of the drug

Drug stability

All of these

The main advantage of using nanotechnology for drug delivery is that it encompasses all of the given options. Nanotechnology allows for successful delivery of drugs to the targeted region of the body, ensuring that the medication reaches the intended site of action. It also enables efficient encapsulation of the drug, protecting it from degradation and enhancing its bioavailability. Additionally, nanotechnology contributes to drug stability, preventing premature drug breakdown and ensuring the drug remains effective until it reaches its target. Therefore, all of these factors make nanotechnology a highly advantageous method for drug delivery.

Explanation

The main advantage of using nanotechnology for drug delivery is that it encompasses all of the given options. Nanotechnology allows for successful delivery of drugs to the targeted region of the body, ensuring that the medication reaches the intended site of action. It also enables efficient encapsulation of the drug, protecting it from degradation and enhancing its bioavailability. Additionally, nanotechnology contributes to drug stability, preventing premature drug breakdown and ensuring the drug remains effective until it reaches its target. Therefore, all of these factors make nanotechnology a highly advantageous method for drug delivery.

76. Which of these is not among the advantages of lowering the activation energy?

It allows chemicals to react that otherwise wouldn't

It allows reactions to proceed more quickly

It changes the optimum pH of the enzyme

It allows reactions to proceed at an acceptable temperature.

Lowering the activation energy allows chemicals to react that otherwise wouldn't, as it lowers the energy barrier for the reaction to occur. It also allows reactions to proceed more quickly, as the lower activation energy speeds up the rate of the reaction. Additionally, it allows reactions to proceed at an acceptable temperature, as the lower activation energy allows the reaction to occur at lower temperatures. However, it does not change the optimum pH of the enzyme, as the pH level affects the enzyme's activity but not the activation energy.

Explanation

Lowering the activation energy allows chemicals to react that otherwise wouldn't, as it lowers the energy barrier for the reaction to occur. It also allows reactions to proceed more quickly, as the lower activation energy speeds up the rate of the reaction. Additionally, it allows reactions to proceed at an acceptable temperature, as the lower activation energy allows the reaction to occur at lower temperatures. However, it does not change the optimum pH of the enzyme, as the pH level affects the enzyme's activity but not the activation energy.

77. Why are enzyme controlled reactions slow at low temperatures?

A lower temperature means the molecules have less kinetic energy, so they do not collide as frequently.

A lower temperature means the molecules have less elastic energy, so they do not bind together as frequently.

A lower temperature means the molecules have more kinetic energy, so they collide frequently.

This is incorrect; most enzyme-controlled reactions will occur quickly at low temperatures.

At low temperatures, the molecules have less kinetic energy, which means they move more slowly. As a result, the frequency of collisions between molecules decreases. Enzyme-controlled reactions rely on collisions between the enzyme and the substrate to occur. Therefore, if the molecules are moving more slowly and colliding less frequently, the rate of enzyme-controlled reactions will be slower at low temperatures.

Explanation

At low temperatures, the molecules have less kinetic energy, which means they move more slowly. As a result, the frequency of collisions between molecules decreases. Enzyme-controlled reactions rely on collisions between the enzyme and the substrate to occur. Therefore, if the molecules are moving more slowly and colliding less frequently, the rate of enzyme-controlled reactions will be slower at low temperatures.

78. The graph below illustrates the free energy of a biochemical reaction, once in the absence of an enzyme and another time in the presence of a specific enzyme. In the presence of the enzyme, the energy of activation of the reaction is lowered from ………. to ……..

(D A) / (A C)

(B A) / (A C)

(D A) / (B A)

(B A) / (B C)

In the presence of the enzyme, the energy of activation of the reaction is lowered from (D A) to (B A). This means that the enzyme helps to decrease the amount of energy required for the reaction to occur, making it easier for the reaction to proceed. The ratio (D A) / (B A) represents the decrease in energy of activation achieved by the enzyme.

Explanation

In the presence of the enzyme, the energy of activation of the reaction is lowered from (D A) to (B A). This means that the enzyme helps to decrease the amount of energy required for the reaction to occur, making it easier for the reaction to proceed. The ratio (D A) / (B A) represents the decrease in energy of activation achieved by the enzyme.

79. The reaction stops completely at high temperature due to the ……. of the enzyme.

Destruction

Formation

Reversibility

Activation

At high temperatures, the enzyme undergoes destruction or denaturation. This means that the enzyme's structure and shape are altered, leading to a loss of its catalytic activity. The destruction of the enzyme at high temperatures prevents it from effectively catalyzing the reaction, causing the reaction to stop completely.

Explanation

At high temperatures, the enzyme undergoes destruction or denaturation. This means that the enzyme's structure and shape are altered, leading to a loss of its catalytic activity. The destruction of the enzyme at high temperatures prevents it from effectively catalyzing the reaction, causing the reaction to stop completely.

80. The diagram below shows a metabolic pathway. What would happen to the rate of production of D if enzyme 1 was not present?

It would be increased.

It would be reduced.

It wouldn't be any different.

It would stop.

If enzyme 1 was not present, it would stop the entire metabolic pathway as enzyme 1 is necessary for the production of D. Without enzyme 1, the reaction that produces D would not be able to occur, leading to the cessation of D production.

Explanation

If enzyme 1 was not present, it would stop the entire metabolic pathway as enzyme 1 is necessary for the production of D. Without enzyme 1, the reaction that produces D would not be able to occur, leading to the cessation of D production.

81. Most enzymes work under a ……… pH range and are ……… in highly acidic or alkaline medium.

Broad, active

Broad, destroyed

Narrow, active

Narrow, destroyed

Most enzymes have a narrow pH range in which they are active. This means that they can only function effectively within a specific pH range. If the pH deviates too much from this optimal range, the enzyme's structure and function can be disrupted, leading to its destruction. Enzymes are highly sensitive to changes in pH, and extreme acidity or alkalinity can denature the enzyme, rendering it inactive or destroyed. Therefore, the correct answer is "Narrow, destroyed."

Explanation

Most enzymes have a narrow pH range in which they are active. This means that they can only function effectively within a specific pH range. If the pH deviates too much from this optimal range, the enzyme's structure and function can be disrupted, leading to its destruction. Enzymes are highly sensitive to changes in pH, and extreme acidity or alkalinity can denature the enzyme, rendering it inactive or destroyed. Therefore, the correct answer is "Narrow, destroyed."

82. Oxidation of glucose during cellular respiration is considered a process of …..

Catabolism

Anabolism

Excretion

Digestion

The oxidation of glucose during cellular respiration is a catabolic process. Catabolism refers to the breakdown of complex molecules into simpler ones, releasing energy in the process. Glucose is broken down into smaller molecules such as carbon dioxide and water, and energy is released in the form of ATP. This process is essential for the production of energy in cells. Anabolism, on the other hand, is the process of building complex molecules from simpler ones, which is not the case during the oxidation of glucose. Excretion and digestion are unrelated processes to the oxidation of glucose.

Explanation

The oxidation of glucose during cellular respiration is a catabolic process. Catabolism refers to the breakdown of complex molecules into simpler ones, releasing energy in the process. Glucose is broken down into smaller molecules such as carbon dioxide and water, and energy is released in the form of ATP. This process is essential for the production of energy in cells. Anabolism, on the other hand, is the process of building complex molecules from simpler ones, which is not the case during the oxidation of glucose. Excretion and digestion are unrelated processes to the oxidation of glucose.

83. Why does the graph level-off at point (B) if you know that the reaction is done at constant temperature and pH ?

Because the enzyme is beginning to denature.

Because the enzyme has been used up.

Because there are not enough substrate molecules left.

Because of the change in the power of hydrogen.

The graph levels off at point (B) because there are not enough substrate molecules left. At the beginning of the reaction, the substrate concentration is high, and the reaction rate increases as more substrate molecules collide with the enzyme. However, as the reaction progresses, the substrate molecules are converted into product, leading to a decrease in substrate concentration. Eventually, the substrate concentration becomes limiting, causing the reaction rate to level off. This is known as substrate depletion, and it explains why the graph levels off at point (B).

Explanation

The graph levels off at point (B) because there are not enough substrate molecules left. At the beginning of the reaction, the substrate concentration is high, and the reaction rate increases as more substrate molecules collide with the enzyme. However, as the reaction progresses, the substrate molecules are converted into product, leading to a decrease in substrate concentration. Eventually, the substrate concentration becomes limiting, causing the reaction rate to level off. This is known as substrate depletion, and it explains why the graph levels off at point (B).

84. The prefix "nano" comes from a ......

French word meaning billion

Greek word meaning dwarf

Spanish word meaning particle

Latin word meaning invisible

The prefix "nano" comes from the Greek word meaning dwarf. This is because the prefix "nano" is used to indicate a billionth of a unit, which is a very small amount. The Greek word for dwarf, "nanos," is used to convey the idea of something being extremely small or tiny, which aligns with the meaning of the prefix "nano."

Explanation

The prefix "nano" comes from the Greek word meaning dwarf. This is because the prefix "nano" is used to indicate a billionth of a unit, which is a very small amount. The Greek word for dwarf, "nanos," is used to convey the idea of something being extremely small or tiny, which aligns with the meaning of the prefix "nano."

85. In the figure below, what is the thermal range of enzyme activity?

10 – 38

10 – 41

30 – 50

10 – 52

The thermal range of enzyme activity refers to the temperature range in which the enzyme can function optimally. In this case, the correct answer is 10 – 38, indicating that the enzyme's activity is optimal between 10 and 38 degrees Celsius.

Explanation

The thermal range of enzyme activity refers to the temperature range in which the enzyme can function optimally. In this case, the correct answer is 10 – 38, indicating that the enzyme's activity is optimal between 10 and 38 degrees Celsius.

86. Which of the following does not describe the anabolic process?

It is a process that occurs in both human and plant cells.

It is the set of pathways that construct and build molecules from smaller units.

It uses ATP as the energy source for this kind of reactions.

It builds muscle mass and tissues.

It is a process of releasing energy stored in the chemical bonds present in the molecules.

Anabolic process is the set of pathways that construct and build molecules from smaller units. It uses ATP as the energy source for these reactions. It builds muscle mass and tissues. However, it does not describe the process of releasing energy stored in the chemical bonds present in the molecules.

Explanation

Anabolic process is the set of pathways that construct and build molecules from smaller units. It uses ATP as the energy source for these reactions. It builds muscle mass and tissues. However, it does not describe the process of releasing energy stored in the chemical bonds present in the molecules.

87. Lactic acid is a waste product that is formed during anaerobic respiration in humans which is a catabolic pathway. Why is it important that lactic acid be removed from the body after exercise?

In high concentrations, lactic acid can build up in arteries and clog them.

Lactic acid is poisonous and can cause blood poisoning.

Lactic acid is toxic at high concentrations and can break down cell walls.

Lactic acid is toxic at high concentrations and can cause muscle pain.

In high concentrations, lactic acid can interact with stomach acid and lower the pH of the body.

Lactic acid is produced during anaerobic respiration when the body doesn't have enough oxygen to break down glucose completely. While small amounts of lactic acid can be cleared by the body, high concentrations can lead to muscle pain and fatigue. This is because lactic acid can disrupt the pH balance in the muscles, leading to an accumulation of hydrogen ions and causing muscle soreness. Therefore, it is important to remove lactic acid from the body after exercise to prevent the buildup of toxic levels and minimize muscle discomfort.

Explanation

Lactic acid is produced during anaerobic respiration when the body doesn't have enough oxygen to break down glucose completely. While small amounts of lactic acid can be cleared by the body, high concentrations can lead to muscle pain and fatigue. This is because lactic acid can disrupt the pH balance in the muscles, leading to an accumulation of hydrogen ions and causing muscle soreness. Therefore, it is important to remove lactic acid from the body after exercise to prevent the buildup of toxic levels and minimize muscle discomfort.

88. Enzymes are completely destroyed at …… ^OC or above.

40

60

10

37

Enzymes are proteins that catalyze chemical reactions in living organisms. They have a specific three-dimensional structure that is essential for their function. When exposed to high temperatures, enzymes can denature, meaning their structure becomes disrupted and they lose their catalytic activity. The given answer, 60°C, suggests that enzymes are completely destroyed at this temperature or above. This is because at such high temperatures, the bonds that maintain the enzyme's structure are broken, rendering the enzyme non-functional.

Explanation

Enzymes are proteins that catalyze chemical reactions in living organisms. They have a specific three-dimensional structure that is essential for their function. When exposed to high temperatures, enzymes can denature, meaning their structure becomes disrupted and they lose their catalytic activity. The given answer, 60°C, suggests that enzymes are completely destroyed at this temperature or above. This is because at such high temperatures, the bonds that maintain the enzyme's structure are broken, rendering the enzyme non-functional.

89. Enzymes generally have …….

Same pH and same optimal temperature.

Same pH but different optimal temperature.

Different pH but same optimal temperature.

Different pH and different optimal temperature.

Enzymes generally have different pH and different optimal temperature because enzymes function optimally at specific pH and temperature ranges. The pH affects the charge distribution of the enzyme and its substrate, altering their interaction. Similarly, temperature affects the enzyme's shape and activity. Therefore, different enzymes have different pH and temperature requirements for efficient catalysis.

Explanation

Enzymes generally have different pH and different optimal temperature because enzymes function optimally at specific pH and temperature ranges. The pH affects the charge distribution of the enzyme and its substrate, altering their interaction. Similarly, temperature affects the enzyme's shape and activity. Therefore, different enzymes have different pH and temperature requirements for efficient catalysis.

90. Pancreatic juice contains …… which plays a role in neutralizing the stomach acids.

Pancreatic amylase

Lipase

Sodium bicarbonate

Trypsin

Sodium bicarbonate is an alkaline substance that helps neutralize the acidic environment in the stomach. When pancreatic juice is released into the small intestine, it helps to counteract the stomach acids and create a more neutral pH. This is important because the enzymes in the small intestine, such as pancreatic amylase and lipase, work best in a slightly alkaline environment. Therefore, sodium bicarbonate plays a crucial role in maintaining the optimal pH for digestion in the small intestine.

Explanation

Sodium bicarbonate is an alkaline substance that helps neutralize the acidic environment in the stomach. When pancreatic juice is released into the small intestine, it helps to counteract the stomach acids and create a more neutral pH. This is important because the enzymes in the small intestine, such as pancreatic amylase and lipase, work best in a slightly alkaline environment. Therefore, sodium bicarbonate plays a crucial role in maintaining the optimal pH for digestion in the small intestine.