Biology Form 4 Test 2

Extracellular enzymes are enzymes that are secreted outside of the cell and function in the extracellular environment. Amylase, pepsin, and trypsin are all examples of extracellular enzymes. Amylase is produced in the salivary glands and pancreas and functions in the breakdown of carbohydrates. Pepsin is produced in the stomach and aids in the digestion of proteins. Trypsin is produced in the pancreas and also aids in protein digestion. These enzymes are released into the digestive system to break down food molecules into smaller, more easily absorbed components.

Maltose, glucose, and galactose are all soluble in water because they are all monosaccharides or disaccharides. These types of carbohydrates have hydrophilic functional groups, such as hydroxyl groups, that can form hydrogen bonds with water molecules, allowing them to dissolve in water. Starch, on the other hand, is a polysaccharide made up of many glucose units and is insoluble in water.

Option 4 represents the enzyme for this reaction because it shows a specific protein structure that is responsible for catalyzing the chemical reaction. The other options do not show any protein structure or do not accurately represent an enzyme.

When fertilizers are dissolved in the soil water, they increase the concentration of solutes in the water. This increased concentration makes the soil water hypertonic compared to the cell sap in the roots. As a result, water diffuses out of the plant cells through osmosis, causing the plant to lose water. This loss of water leads to the cells becoming plasmolysed, which means that the cytoplasm shrinks away from the cell wall. Therefore, both statements explain the phenomena observed in the diagram.

Facilitated diffusion is a passive process, meaning it does not require the cell to expend energy. It involves the use of carrier proteins to transport molecules across the cell membrane.

Active transport is the process by which particles are moved from a region of lower concentration to a region of higher concentration. This movement requires energy, which is obtained from respiration. Unlike passive transport, which relies on concentration gradients, active transport allows cells to transport molecules against their concentration gradient, ensuring that essential substances are taken up and waste products are expelled. This process is crucial for maintaining homeostasis and ensuring the proper functioning of cells and organisms.

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The basic unit composition of fat is one molecule of glycerol and three molecules of fatty acids. This means that when fats are broken down, they are composed of one glycerol molecule and three fatty acid molecules.

The factors that affect the changes of structure protein A to structure protein B are pH and temperature. pH refers to the acidity or alkalinity of the environment and can alter the charges on amino acid residues, affecting the protein's structure. Temperature can denature proteins by disrupting the weak bonds that stabilize their structure. Salt concentration and humidity are not mentioned as factors that affect the changes in protein structure in the given information.

Organelles Q, R, and S are involved in the synthesis and secretion of extracellular enzymes. Organelle Q is likely the endoplasmic reticulum (ER), which is responsible for protein synthesis and modification. Organelle R is likely the Golgi apparatus, which receives proteins from the ER and further modifies and packages them for secretion. Organelle S is likely the secretory vesicles, which transport the packaged enzymes to the cell membrane for secretion. Therefore, organelles Q, R, and S are involved in the synthesis and secretion of extracellular enzymes.

Proteins are composed of long chains of amino acids, which are the basic monomer units of proteins. Amino acids are organic compounds that contain both an amino group (-NH2) and a carboxyl group (-COOH). They are joined together through peptide bonds to form polypeptide chains, which then fold into specific 3D structures to create proteins. Therefore, the correct answer is amino acids or amino acid.

Water is considered a good solvent because it has the ability to dissolve many substances. This is due to its unique molecular structure, which allows it to form hydrogen bonds with other molecules. These hydrogen bonds help to break apart the solute particles and surround them, dispersing them evenly throughout the water. As a result, water can dissolve a wide variety of substances, making it an effective solvent in many chemical reactions and biological processes.

In order to accurately investigate the effect of temperature on the action of amylase, it is important to keep certain conditions the same in each of the six test-tubes. The concentration of amylase should be kept the same to ensure that any observed differences in the reaction are solely due to the temperature variation and not because of differences in enzyme concentration. The pH should also be kept the same as it can affect the activity of the enzyme. Additionally, the volume of starch solution should be kept the same to ensure that the enzyme-substrate ratio remains constant across all test-tubes.

From the diagram, it can be deduced that the enzymatic action is specific because the enzyme is shown to interact with a specific substrate. Additionally, it can be concluded that the enzyme is not destroyed at the end of the reaction because it is shown to be separate from the product. However, the diagram does not provide information about the optimum temperature for enzymatic reaction or whether the enzymatic reaction is reversible.

Catalysts are substances that speed up biochemical reactions without being consumed or changed by the reaction. This means that they remain unchanged at the end of the reaction and can be used again. Therefore, the characteristics of all catalysts are that they speed up biochemical reactions and they are not changed by the reaction.

The low pH of the preserved vegetable creates an environment that is not suitable for bacterial growth. Bacteria require a neutral or slightly alkaline environment to thrive, and the acidity of the low pH inhibits their growth. This helps to prevent spoilage and allows the vegetables to last longer.

The correct sequence is S → P → R → Q. First, the housewife cuts the meat into small pieces (S). Then, she adds the raw papaya slices to tenderize the meat (P). After that, she leaves the meat for one and a half hours (R) to allow the papaya to work its tenderizing magic. Finally, she boils the meat (Q) to cook it for dinner.

The jar of air being placed upside down on top of the jar containing the brown gas allows for diffusion to occur in both directions. Diffusion is the movement of particles from an area of high concentration to an area of low concentration. In this case, the air particles in the jar will move downwards into the jar containing the brown gas, while the brown gas particles will move upwards into the jar of air. Therefore, diffusion is happening both upwards and downwards.

Protease is an enzyme that breaks down proteins. The diagram shows that the protease used in the experiment was taken from a human stomach. The stomach is known to have a highly acidic environment, which is ideal for the activity of protease enzymes. Test-tube C, which contains the protease from a human stomach, is likely to have the most acidic environment compared to the other test-tubes. Therefore, the protein in test-tube C will be digested most quickly due to the optimal conditions for the protease enzyme.

Water is the substance K in the cell because it acts as a medium for biochemical reactions in cells and helps maintain the osmotic pressure of cells. Water is essential for various cellular processes, such as transportation of nutrients, removal of waste, and facilitating chemical reactions. It is also involved in maintaining the shape and structure of cells.

In the diagram, it can be observed that the mass of the potato strips decreased when placed in the 35% concentration of sucrose solution. This indicates that water moved out of the potato cells, causing them to shrink. This suggests that the concentration of the sucrose solution is higher than the concentration of solutes inside the potato cells, making the 35% concentration hypertonic to the potato cells.

Tube D would contain the most sugar after 20 minutes because it contains both the enzyme amylase and the substrate starch. Amylase is responsible for breaking down starch into sugar molecules, so having both the enzyme and substrate present in tube D would result in the highest amount of sugar being produced.

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Both diffusion and osmosis involve the movement of molecules from an area of higher concentration to an area of lower concentration. This is known as moving down the concentration gradient. Therefore, the statements "molecules move from higher concentration to lower concentration" and "require a concentration gradient" are correct for both diffusion and osmosis.

The question asks for the number of naturally-occurring amino acids. Amino acids are the building blocks of proteins and there are 20 different amino acids that are commonly found in living organisms. Each amino acid has a unique side chain, which gives it different properties and functions. Therefore, the correct answer is 20.

The characteristic described in the statement is that maltase can speed up both the hydrolysis and condensation process. This implies that the reaction catalyzed by maltase can proceed in both directions, meaning it is reversible.

The correct answer is carbon, hydrogen, and oxygen. Carbohydrates are organic compounds composed of these three elements. Carbon forms the backbone of the carbohydrate molecule, while hydrogen and oxygen are present in the same ratio as water (H2O). These elements are essential for the structure and function of carbohydrates, which serve as a major source of energy in living organisms.

P is the Phosphate group, Q is the Deoxyribose sugar, and R is the Nitrogenous base. These are the components that make up a nucleotide, which is the building block of DNA. The phosphate group provides the backbone of the DNA molecule, the deoxyribose sugar forms the sides of the DNA ladder, and the nitrogenous base pairs with another base to form the rungs of the DNA ladder. Together, these components create the structure of DNA.

The molecular structure of P corresponds to a protein, while the molecular structure of Q corresponds to a lipid.

The diagram shows a plasma membrane, which consists of a phospholipid bilayer. The phospholipids have a hydrophilic head and hydrophobic tail. The hydrophilic head is attracted to water and faces the aqueous environment both inside and outside of the cell. The hydrophobic tail is repelled by water and is sandwiched between the hydrophilic heads, creating a barrier that prevents water-soluble molecules from freely passing through the membrane. Therefore, the parts labelled I and II correspond to the hydrophilic head and hydrophobic tail, respectively.

Oxygen diffuses into the blood from an alveolus in the lungs because the oxygen concentration in the alveolus is greater than in the blood. This concentration gradient allows oxygen molecules to move from an area of high concentration (alveolus) to an area of low concentration (blood) through diffusion.

The process X in the given diagram is plasmolysis, which is the shrinkage or contraction of the protoplasm of a plant cell due to the loss of water through osmosis. The process Y is deplasmolysis, which is the reverse process of plasmolysis, where the protoplasm of a plant cell regains water and returns to its original state.

The deduction that can be made about enzymes from the given information is that enzymes can build up large molecules. This can be inferred from the fact that when enzyme 1 is changed to enzyme 2, it slows down the production of amino acids. This suggests that enzyme 2 is involved in the synthesis or building up of amino acids, which are large molecules.

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The diagram shows that each piece of carrot root is treated differently. Option 3 is the piece that is boiled for two hours. Boiling carrots for a long time causes them to become soft and lose their shape, so the boiled carrot will likely be the smallest piece after two hours.

The most likely reason for the color change in the water is that molecules of red ink moved through the membrane by diffusion. This means that the red ink molecules moved from an area of higher concentration (the red ink solution) to an area of lower concentration (the water in the beaker) until equilibrium was reached. This movement of molecules is characteristic of diffusion, where particles move from an area of high concentration to an area of low concentration. Osmosis, on the other hand, refers specifically to the movement of water molecules through a selectively permeable membrane, so it is not the most likely reason for the color change in this scenario.

The strip immersed in the hypotonic solution would have absorbed water and become swollen. In a hypotonic solution, the concentration of solutes outside the cell is lower than inside the cell, causing water to move into the cell by osmosis. Therefore, the strip in Option 4 would have been immersed in the hypotonic solution.

Silk is an example of a protein because it is produced by certain insects, such as silkworms, as a fibrous protein called fibroin. This protein is spun into silk threads to create cocoons. Proteins are large molecules made up of amino acids and have a wide range of functions in living organisms, including structural support, enzymatic activity, and transportation of molecules. Steroids, waxes, and glycogen are not proteins, as they have different chemical structures and functions.

Lipase is an enzyme that breaks down fats into smaller molecules. DNA carries the code for making various substances in the body, including enzymes like lipase. Therefore, lipase is the correct answer as it is the substance that is coded for by the DNA in a human cell.

The diagram shows the relationship between the rate of reaction and substrate concentration when a factor P is varied. The options given are time, pH, temperature, and enzyme concentration. From the diagram, it can be observed that as the enzyme concentration increases, the rate of reaction also increases. This suggests that factor P is the enzyme concentration, as it directly affects the rate of reaction.

When two amino acids combine, they form a dipeptide. A dipeptide is a molecule composed of two amino acids joined together by a peptide bond. The formation of a dipeptide involves the removal of a water molecule, a process known as condensation or dehydration synthesis. Therefore, the given equation represents the reaction where two amino acids combine to form a dipeptide and release water as a byproduct. The term "dipeptides" is used to refer to multiple dipeptide molecules.

In process P, sucrose is broken down into its constituent parts, glucose and fructose, through the addition of water. Therefore, the word equation for process P is "sucrose + water -> glucose + fructose".

Option 4 shows the mass changes correctly because as the concentration of sucrose solution increases, the mass of the potato decreases. This is evident from the negative slope of the graph in Option 4. The other options either show incorrect relationships between concentration and mass or do not show any clear trend.

Curve D represents the result of the experiment because it shows an increase in the activity of salivary amylase over time. This is indicated by the upward slope of the curve. Curves A, B, and C either show a decrease in activity or no change in activity, which is not consistent with the experiment. Therefore, curve D is the correct representation of the experiment's result.

Young plants are supported by the pressure of water inside the cells pressing outwards on the cell walls. This pressure, known as turgor pressure, helps to maintain the shape and rigidity of the plant cells, providing support for the growing plant.

Option 3 is the best representation of the effect of pH on the rate of reaction of enzymes in the duodenum because it shows an increase in enzyme activity as the pH increases from acidic to slightly alkaline levels, reaching an optimal pH where the reaction rate is highest. After the optimal pH, the enzyme activity decreases as the pH becomes more alkaline. This graph demonstrates the typical bell-shaped curve that represents the relationship between pH and enzyme activity.

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The given DNA template sequence is TACTTCCCTATTTTCATGTA. In DNA, T (thymine) pairs with A (adenine), A pairs with T, C (cytosine) pairs with G (guanine), and G pairs with C. Therefore, the mRNA sequence will have complementary bases, replacing T with U (uracil). So, the mRNA sequence is AUGAAGGAUAAAGUACAU.