Enzymatics
1. Which of the following is TRUE about a metabolic pathway?
ATP is required at each step.
A final end product is never produced.
The products become the next substrates.
The same enzyme is used each step in the pathway.
2. Which of the following is NOT TRUE about enzymes?
Participants in reactions.
Stored in a cell’s active site.
Very specific in their function.
Denatured by high temperatures.
3. Which of the following is NOT TRUE about enzymes?
Protein substances.
Organic substances.
Regulate metabolism.
Consumed in reactions.
4. Which part of a person’s diet supplies them with co-enzymes?
Lipids.
Proteins.
Vitamins.
Carbohydrates.
5. Which part of a person’s diet supplies them with co-factors?
Fats.
Water.
Minerals.
Vitamins.
6. Which of the following is NOT TRUE about enzymatic reactions?
Enzymes can be used repeatedly.
Enzymes each catalyze only one specific reaction.
Substrates temporarily bond onto enzymes for a reaction to occur.
The energy of activation required for a reaction is increased by the presence of enzymes.
7. Which of the following factors will NOT denature an enzyme?
pH.
Temperature.
Concentration.
Heavy metal ions.
Use the following reaction to answer the next question.
8. Which letter refers to the enzyme in this reaction?
V
W
X
Y
9. Which of the following steps occurs FIRST during a hydrolytic reaction?
The substrate is broken.
The active site changes shape.
The substrate bonds to the active site.
Water molecules are broken and used.
Use the following reaction to answer the next two questions.
10. Which component is made at a cell’s ribosomes?
E
S
P
None of them are.
11. Which reaction component is temperature and pH sensitive?
E
S
P
None of them are.
12. A particular reaction that occurs in the mouth was proceeding in a test tube at 45 degrees and at a pH of 2.5. Which of the following would likely cause the greatest INCREASE in the reaction rate?
Drop 10 degrees and increase the pH.
Drop 10 degrees and maintain the pH.
Raise 10 degrees and maintain the pH.
Raise 10 degrees and decrease the pH.
13. Which of the following conditions for an enzyme-catalyzed reaction will produce the LEAST product?
Low [Substrate], low [Enzyme].
Low [Substrate], high [Enzyme].
High [Substrate], low [Enzyme].
High [Substrate], high [Enzyme].
14. Where does the energy for enzymatic reactions come from?
ATP.
Enzymes.
Substrates.
Co-enzymes.
15. Consider the following statements and select the BEST order for an enzyme-catalyzed reaction.
1. The chemical reaction occurs.
2. The enzyme is released unchanged.
3. The substrate pieces are combined to form a product.
4. The substrate pieces fit into the active site of the enzyme.
1, 4, 3, 2
2, 1, 3, 4
4, 1, 3, 2
4, 2, 3, 1
16. One of the following factors affecting enzymatic activity will often allow the enzymes to “renature” when the condition is returned to normal. Which one is it?
A pH much lower than optimum.
A pH much higher than optimum.
A temperature much lower than optimum.
A temperature much higher than optimum.
17. What level of structure is affected when an enzyme gets denatured?
Primary.
Secondary.
Tertiary.
Quaternary.
18. Which of the following is the least likely to affect the rate of enzymatic activity?
pH.
Temperature.
Concentration.
Osmotic pressure.
19. An enzyme’s ability to “recognize” the appropriate substrate is based on
mass.
shape.
reactivity.
glycoproteins on their surfaces.
20. Which of the following is TRUE about hydrolytic enzymes?
They cannot be stored in cells.
They bond onto proteins to react.
They are denatured at very high temperatures.
Their function almost never involves co-enzymes.
21. Which of the following is not true about enzymes?
They lower activation energy.
They are environmentally sensitive.
Their shape is very specific to their function.
hey are made out of repeating nucleotide units.
Use the following diagram to answer the next two questions.
22. At which step(s) in this reaction sequence are co-enzymes and co-factors the MOST involved?
Step 1.
Step 2.
Step 3.
Step 1 or 2, but not Step 3.
23. Which of the following is the MOST probable identity of V?
ATP.
Maltose.
Glucose.
Calcium.
24. Generally, increasing the enzyme concentration in an enzymatic reaction will cause the reaction to
stop.
reverse.
speed up.
slow down.
Use the following graph to answer the next question.
25. The difference between line “a” and line “b” represents the effect of
adding enzymes.
establishing optimum pH.
establishing optimum temperature.
increasing the substrate concentration.
26. Which of the following is not true for enzymes?
They are produced by cells.
They can react only when inside cells.
They can be destroyed by high temperatures.
They are generally considered to be proteins.
27. Which of the following is not true about enzymatic reactions?
Substrates get consumed.
Once started they can’t be stopped.
Chemical bonds are either broken or formed.
The shape of the enzyme’s active sites is temporarily affected.
28. If a substrate concentration is increased, the amount of product formed normally should
increase.
decrease.
decrease and stop.
remain unchanged.
29. Which of the following is not true for enzymes?
Their name ends with the suffix “ase.”
They each react with only one type of substrate.
They increase the amount of energy required to start a reaction.
They form an association with the substrate before the actual reaction.
30. Which of the following is true for enzymes?
They can be used repeatedly.
They increase the energy of activation.
They are often named after their solute.
They are not always specific in their function.
31. Which of the following will not change the shape of an active site?
Altering the pH.
Adding heavy metal ions.
Increasing the temperature.
Adding competitive inhibitors.
32. Select the FALSE statement from the following choices.
The Kinetic Molecular Theory applies to enzymatic activity.
Enzyme-catalyzed reactions rarely occur without the enzyme.
Enzymes work best when certain vitamins and minerals are present.
Some enzymes can react with several different shapes of substrates.
33. How does Hg
2+
affect enzyme activity?
It alters the pH, which affects the enzyme’s ability to function.
It combines with the substrate preventing it from reaching the active site.
It combines with the active site to prevent the substrate from binding there.
It causes the redistribution of electrons in the enzyme which causes a distortion in its shape.
Use the following diagram to answer the next question.
34. If substance D inhibits Enzyme 2 (E
2
), this will in turn inhibit the production of
Substance D only.
Substance F only.
both Substances D and F.
Enzymes 3 and 4 (E
3
and E
4
).
35. At which of the following conditions does the rate of enzymatic activity DECREASE as predicted by the Kinetic Molecular Theory?
At a pH less than optimum.
At a pH greater than optimum.
At a temperature less than optimum.
At a temperature greater than optimum.