Question

1. a scientist is using an enzyme to get a chemical reaction to occur within a cell sample and observes that the reaction occurs best when the ph is lowered to 6.2. what does this experiment most likely demonstrate?

a enzyme specificity
b. enzymes are reusable
c. ph affects enzyme function
d. enzymes lower activation energy

1. the enzyme amylase can digest carbohydrates, but it cannot digest proteins. which explains the effect of amylase on the digestion of carbohydrates compared to proteins?

a amylase is a protein, so it is restricted to acting on non-protein molecules such as carbohydrates.
b. amylase can digest carbohydrates because it is an enzyme, but proteins cannot be digested by enzymes.
c. amylase can digest carbohydrates because carbohydrates, unlike proteins, are excellent sources of cellular energy.
d. amylase lowers the activation energy required for the digestion of carbohydrates, but has no impact on the activation energy required to digest proteins.

1. the enzyme hexokinase binds to glucose and atp during the chemical reaction. at what location do they connect?

a active site
b. between the bases
c. at the end of the fatty acids
d. the enzyme - substrate complex

1. why are enzymes essential to all multicellular organisms?

a they provide insulation.
b. they produce living tissue.
c. they contain genetic information.
d. they catalyze metabolic reactions.

Explanation:

• Question 14: The experiment shows that changing the pH (lowering it to 6.2) affects the enzyme - catalyzed reaction. Enzyme specificity (A) is about the enzyme acting on a specific substrate. Enzymes being reusable (B) is about the enzyme not being consumed in the reaction. Enzymes lowering activation energy (D) is a general property of enzymes, but the key here is the pH change. Since the reaction is best at a specific pH, it shows that pH affects enzyme function.
• Question 15: Enzymes work by lowering the activation energy of a reaction. Amylase can act on carbohydrates because it lowers the activation energy for carbohydrate digestion, but it has no effect on the activation energy for protein digestion. Option A is incorrect because an enzyme's protein nature does not restrict it from acting on proteins. Option B is wrong as proteins can be digested by enzymes (e.g., proteases). Option C is incorrect because the energy - source property of carbohydrates is not related to amylase's specificity.
• Question 16: The active site is the region on the enzyme where the substrate (in this case, glucose and ATP) binds. Between the bases (B) is relevant in nucleic acids. At the end of fatty acids (C) is not relevant to enzyme - substrate binding. The enzyme - substrate complex (D) is the whole structure formed after binding, not the location of connection.
• Question 17: Enzymes are biological catalysts. They speed up (catalyze) metabolic reactions. Providing insulation (A) is a function of fats. Producing living tissue (B) is a function of cells differentiating and growing. Containing genetic information (C) is a function of nucleic acids (DNA, RNA).

Answer:

1. C. pH affects enzyme function
2. D. Amylase lowers the activation energy required for the digestion of carbohydrates, but has no impact on the activation energy required to digest proteins.
3. A. active site
4. D. They catalyze metabolic reactions.