1.
What does a catalyst do to a reaction?
Correct Answer
B. Speed it up
Explanation
A catalyst is a substance that increases the rate of a chemical reaction by lowering the activation energy required for the reaction to occur. It does not force the reaction to happen or prevent it from happening, but rather provides an alternative pathway for the reaction to proceed more easily. Therefore, the correct answer is "Speed it up."
2.
NWhat do we call biological catalysts?
Correct Answer
C. Enzymes
Explanation
Enzymes are known as biological catalysts because they speed up chemical reactions in living organisms without being consumed in the process. They lower the activation energy required for a reaction to occur, allowing it to happen more quickly. Enzymes are highly specific and can only catalyze specific reactions. They play a crucial role in various biological processes such as metabolism, digestion, and cellular signaling. Inhibitors, on the other hand, are substances that decrease or prevent enzyme activity, so they are not the correct answer. Therefore, the correct answer is Enzymes.
3.
Enzymes are what type of biological molecule?
Correct Answer
A. Protein
Explanation
Enzymes are a type of biological molecule called proteins. Proteins are large, complex molecules made up of amino acids. Enzymes play a crucial role in catalyzing chemical reactions in living organisms by speeding up the rate of these reactions. They are involved in various biological processes such as digestion, metabolism, and DNA replication. Therefore, the correct answer is protein.
4.
What is the function of an enzyme?
Correct Answer
B. Speed up a chemical reaction
Explanation
Enzymes are biological catalysts that speed up chemical reactions by lowering the activation energy required for the reaction to occur. They do not get consumed or altered during the reaction and can be reused. Enzymes work by binding to specific substrates and facilitating the conversion of reactants into products. Therefore, the correct answer is "Speed up a chemical reaction."
5.
What is the activation energy for a chemical reaction?
Correct Answer
B. The amount of energy required to get the reaction started
Explanation
The activation energy for a chemical reaction refers to the amount of energy required to initiate or start the reaction. It is the minimum amount of energy that reactant molecules must possess in order to undergo the necessary chemical changes and form products. Once the reaction is started, it may continue to release or require more energy, but the activation energy specifically pertains to the energy needed to initiate the reaction.
6.
What does an enzyme do to the activation energy of a chemical reaction?
Correct Answer
B. Decrease it
Explanation
Enzymes are biological catalysts that speed up chemical reactions by lowering the activation energy required for the reaction to occur. By decreasing the activation energy, enzymes make it easier for the reactant molecules to reach the transition state and form products. This allows the reaction to proceed at a faster rate and with less energy input. Therefore, the correct answer is "Decrease it."
7.
What do we call the starting materials for a chemical reaction?
Correct Answer
A. Reactants
Explanation
Reactants are the starting materials for a chemical reaction. They are the substances that undergo a chemical change during the reaction and are transformed into products. Reactants are the substances that are present before the reaction takes place and are consumed in the process. Catalysts, on the other hand, are substances that speed up the reaction but are not consumed in the process. Therefore, the correct answer is Reactants.
8.
What do we call the materials which are made in a chemical reaction?
Correct Answer
B. Products
Explanation
In a chemical reaction, the materials that are formed as a result of the reaction are called products. Reactants are the materials that are present at the beginning of the reaction and undergo a change, while catalysts are substances that speed up the reaction without being consumed. Therefore, the correct answer is "Products" as it refers to the materials made in a chemical reaction.
9.
Is an enzyme used up during a chemical reaction?
Correct Answer
B. No
Explanation
Enzymes are not used up during a chemical reaction. Enzymes act as catalysts, meaning they speed up the reaction without being consumed or permanently altered in the process. They can be reused multiple times and are only required in small amounts to facilitate the reaction. Therefore, the correct answer is "No."
10.
What happens in a hydrolysis reaction?
Correct Answer
B. Water is used to split another molecule
Explanation
In a hydrolysis reaction, water is used to split another molecule. This process involves the breaking of a chemical bond by the addition of a water molecule, resulting in the formation of two new molecules. This reaction is commonly observed in biological systems, where enzymes facilitate the hydrolysis of complex molecules into simpler components. Therefore, the correct answer is "Water is used to split another molecule."
11.
What do we call the part of the enzyme which binds the substrate?
Correct Answer
A. Active site
Explanation
The part of the enzyme that binds the substrate is called the active site. This is where the chemical reaction takes place, as the substrate fits into the active site and is converted into products. The active site has a specific shape and chemical properties that allow it to bind to the substrate with high specificity. The other options, allosteric site and catalyst, are not the correct terms for the part of the enzyme that binds the substrate.
12.
What is special about the shape of an enzyme's active site?
Correct Answer
C. It fits the substrate shape exactly
Explanation
The shape of an enzyme's active site is special because it fits the substrate shape exactly. This allows for a specific and precise interaction between the enzyme and its substrate, leading to efficient catalysis of the reaction. The complementary shapes of the active site and substrate ensure that only the correct substrate can bind to the enzyme, preventing unwanted reactions. This specificity is crucial for the enzyme to carry out its function effectively.
13.
What do we call the reactants in a chemical reaction when an enzyme is used to speed up the reaction?
Correct Answer
B. Substrates
Explanation
In a chemical reaction where an enzyme is used to speed up the reaction, the reactants are referred to as substrates. Enzymes are catalysts that facilitate chemical reactions by binding to specific substrates and lowering the activation energy required for the reaction to occur. Therefore, in the presence of an enzyme, the reactants are called substrates.
14.
Where does a substrate bind an enzyme?
Correct Answer
C. Active site
Explanation
The active site is where a substrate binds to an enzyme. This is the specific region on the enzyme where the substrate molecule fits and undergoes a chemical reaction. The active site has a unique shape and chemical properties that allow it to bind to the substrate with high specificity. This binding is crucial for the enzyme to catalyze the reaction and convert the substrate into a product. Therefore, the correct answer is active site.
15.
Can an enzyme have more than one substrate?
Correct Answer
D. All of the above
Explanation
Enzymes can have more than one substrate because they can bind to different molecules as long as the substrates are similar in shape. Additionally, some enzymes have the ability to bind to two molecules simultaneously during a synthesis reaction. Furthermore, certain enzymes can modify the shape of their active site in order to accommodate multiple substrates. Therefore, all of the given statements are correct explanations for an enzyme having more than one substrate.
16.
Which model of enzyme activity states that an enzyme's active site has a shape which matches the substrate site very precisely?
Correct Answer
A. Lock and key model
Explanation
The lock and key model of enzyme activity states that an enzyme's active site has a shape that is complementary to the shape of its substrate. This means that the active site and substrate fit together like a lock and key, allowing for a precise and specific interaction. According to this model, the enzyme and substrate do not change their shape during the reaction.
17.
Which model of enzyme activity states that an enzyme's active site will change shape slightly to fit one or more substrates when they bind?
Correct Answer
B. Induced fit model
Explanation
The induced fit model of enzyme activity states that an enzyme's active site will change its shape slightly to fit one or more substrates when they bind. This model suggests that the enzyme and substrate undergo conformational changes upon interaction, resulting in a better fit and facilitating the catalytic reaction. Unlike the lock and key model, which implies a rigid active site, the induced fit model allows for flexibility and adaptation of the active site to accommodate different substrates. The catalyst model is not a recognized model of enzyme activity, so it is not the correct answer.
18.
What do we call a molecule that binds to an enzyme and prevents the enzyme from catalyzing a reaction?
Correct Answer
B. Inhibitor
Explanation
An inhibitor is a molecule that binds to an enzyme and prevents the enzyme from catalyzing a reaction. It acts by blocking the active site of the enzyme, thereby preventing the substrate from binding and the reaction from occurring. Inhibitors can be competitive, where they compete with the substrate for binding to the active site, or non-competitive, where they bind to a different site on the enzyme and cause a conformational change that inhibits the enzyme's activity. Therefore, an inhibitor is the correct answer to the question.
19.
YmAll of the energy on Earth comes from what source?
Correct Answer
A. Sun
Explanation
All of the energy on Earth comes from the Sun. The Sun provides heat and light energy through a process called nuclear fusion. This energy is then converted and utilized by various sources on Earth, such as plants through photosynthesis, chemical reactions in the form of fossil fuels, and ultimately all living organisms that rely on these energy sources. Therefore, the correct answer is the Sun.
20.
What organelle present in plants converts light energy into chemical energy?
Correct Answer
B. Chloroplast
Explanation
Chloroplast is the correct answer because it is the organelle present in plants that converts light energy into chemical energy through the process of photosynthesis. Mitochondrion is responsible for converting chemical energy into usable energy in the form of ATP, while ribosomes are involved in protein synthesis. Therefore, neither mitochondrion nor ribosome convert light energy into chemical energy in plants.
21.
Which of the following substances is a reactant for photosynthesis?
Correct Answer
A. Carbon dioxide
Explanation
Carbon dioxide is a reactant for photosynthesis because it is used by plants, algae, and some bacteria to produce glucose and oxygen through the process of photosynthesis. During photosynthesis, carbon dioxide is taken in from the atmosphere and combined with water to produce glucose, which is a form of sugar, and oxygen. Therefore, carbon dioxide is an essential component for the production of glucose and oxygen in the process of photosynthesis.
22.
Which of the following substances is a reactant for photosynthesis?
Correct Answer
D. All of the above
Explanation
All of the above substances are reactants for photosynthesis. Water is used during the light-dependent reactions to produce oxygen and ATP. Carbon dioxide is used during the light-independent reactions (Calvin cycle) to produce glucose. Light is the energy source that is absorbed by chlorophyll molecules in the chloroplasts, which initiates the process of photosynthesis. Therefore, all three substances are necessary for photosynthesis to occur.
23.
Which of the following substances is a product of photosynthesis?
Correct Answer
E. None of the above
Explanation
The correct answer is "None of the above" because the products of photosynthesis are glucose (a type of sugar) and oxygen. Water and carbon dioxide are the raw materials used in photosynthesis, and light is the energy source, but they are not the end products of the process.
24.
Which of the following substances is a product of photosynthesis?
Correct Answer
C. Oxygen
Explanation
Oxygen is a product of photosynthesis. During photosynthesis, plants use sunlight, water, and carbon dioxide to produce glucose (a type of sugar) and oxygen. The process takes place in the chloroplasts of plant cells, specifically in the thylakoid membranes. Oxygen is released as a byproduct of photosynthesis and is essential for the survival of many organisms, including humans, as it is used in cellular respiration to produce energy. Therefore, out of the given options, oxygen is the correct answer.
25.
Which of the following substances is a product of photosynthesis?
Correct Answer
D. All of the above
Explanation
All of the above substances are products of photosynthesis. ATP is produced during the light-dependent reactions of photosynthesis and is used as an energy source in various cellular processes. Sugars, such as glucose, are also produced during photosynthesis and serve as a source of energy for plants. Oxygen is released as a byproduct of photosynthesis through the process of photolysis, where water molecules are split and oxygen is released into the atmosphere. Therefore, all three substances - ATP, sugar, and oxygen - are produced during photosynthesis.
26.
Which of the following substances is a product of cellular respiration?
Correct Answer
A. ATP
Explanation
ATP is the correct answer because it is produced during cellular respiration. Cellular respiration is the process by which cells convert glucose and oxygen into carbon dioxide, water, and energy in the form of ATP. ATP is the main energy currency of the cell and is used for various cellular processes and activities. Therefore, ATP is a product of cellular respiration.
27.
Which of the following substances is a product of cellular respiration?
Correct Answer
D. All of the above
Explanation
All of the above substances are products of cellular respiration. Water is produced as a result of the electron transport chain in the mitochondria. ATP, or adenosine triphosphate, is the main energy molecule produced during cellular respiration. Carbon dioxide is a waste product that is released during the process of breaking down glucose to produce energy. Therefore, all three substances are produced as a result of cellular respiration.
28.
Which of the following substances is a reactant for cellular respiration?
Correct Answer
A. Oxygen
Explanation
Oxygen is a reactant for cellular respiration because it is required for the process of breaking down glucose and producing ATP, which is the main energy source for cells. Oxygen is used in the final step of cellular respiration called the electron transport chain, where it accepts electrons and combines with hydrogen ions to form water. Without oxygen, cellular respiration cannot proceed, and cells would not be able to generate the necessary energy for their functions. Therefore, oxygen is a crucial reactant in cellular respiration.
29.
Which of the following substances is a reactant for cellular respiration?
Correct Answer
A. Sugar
Explanation
Sugar is the correct answer because it is one of the reactants for cellular respiration. During cellular respiration, sugar (glucose) is broken down in the presence of oxygen to produce energy in the form of ATP. This process occurs in the mitochondria of cells and is essential for the functioning of all living organisms. ATP and carbon dioxide are also involved in cellular respiration, but they are not the reactants.
30.
Cellular respiration happens in which of the following organelles?
Correct Answer
A. Mitochondrion
Explanation
Cellular respiration is the process by which cells convert glucose and oxygen into energy, carbon dioxide, and water. This process occurs in the mitochondrion, which is known as the "powerhouse" of the cell. The mitochondrion contains enzymes and other molecules necessary for the various steps of cellular respiration, such as glycolysis, the Krebs cycle, and oxidative phosphorylation. Therefore, the correct answer is Mitochondrion.
31.
What does ATP stand for?
Correct Answer
B. Adenosine triphosphate
Explanation
ATP stands for Adenosine triphosphate. Adenosine triphosphate is a molecule that stores and provides energy for cellular processes in organisms. It is often referred to as the "energy currency" of the cell. ATP is composed of adenosine, a nucleoside, and three phosphate groups. When one of the phosphate groups is broken off, energy is released and can be used by the cell for various functions. Therefore, the correct answer is Adenosine triphosphate.
32.
What sugar is contained in ATP?
Correct Answer
B. Ribose
Explanation
ATP (adenosine triphosphate) is a molecule that stores and provides energy for cellular processes. It consists of three components: adenine, ribose, and phosphate. Adenine is a nitrogenous base, ribose is a sugar molecule, and phosphate is a group of molecules containing phosphorus. Therefore, the correct answer is ribose, as it is the sugar contained in ATP.
33.
What nucleotide is contained in ATP?
Correct Answer
A. Adenine
Explanation
ATP (adenosine triphosphate) is a molecule that serves as the main energy source for cellular processes. It consists of three phosphate groups, a ribose sugar, and an adenine base. Adenine is a nucleotide base that is present in ATP, making it the correct answer. Thymine is not found in ATP, as it is a base specific to DNA. Phosphate is also present in ATP, as it is part of the phosphate groups that make up the molecule. Therefore, "All of the above" is not the correct answer, and "None of the above" is also incorrect.
34.
What do you get when you remove a phosphate from ATP?
Correct Answer
A. ADP
Explanation
When a phosphate is removed from ATP, it forms ADP (adenosine diphosphate). ATP is a molecule that stores and releases energy in cells, and when a phosphate group is removed, it releases energy and becomes ADP. ADP can then be converted back into ATP through the addition of a phosphate group, allowing it to store energy again.
35.
How many phosphates does ATP have?
Correct Answer
C. 3
Explanation
ATP (adenosine triphosphate) has three phosphate groups. This molecule is commonly referred to as the "energy currency" of cells because it stores and releases energy during cellular processes. The high-energy bonds between the phosphate groups can be broken to release energy, which is used to fuel various biological reactions. Therefore, the correct answer is 3.
36.
Why does the cell break a phosphate off ATP?
Correct Answer
C. To make energy
Explanation
The cell breaks a phosphate off ATP to make energy. ATP (adenosine triphosphate) is the primary molecule used by cells to store and transfer energy. When a phosphate group is removed from ATP, it releases energy that can be used for various cellular processes. Therefore, breaking a phosphate off ATP is a crucial step in the production of energy within the cell.