Enzyme Practice Quiz

Which of the following enzymes would digest a fat?
1. sucrase
2. fatase
3. protease
4. lipase
At high temperatures, the rate of enzyme action decreases because the increased heat
1. changes the pH of the system
2. alters the active site of the enzyme
3. neutralizes the acids and bases in the system
4. increases the concentration of the enzyme
Enzymes influence chemical reactions in living systems by
1. providing the substrate required for the reaction to occur
2. affecting the rate at which reactions occur
3. absorbing water released when polymers are formed
4. combining with excess hydrogen to form gaseous wastes
Which group of organic compounds includes the enzymes?
1. proteins
2. starches
3. carbohydrates
4. lipids
The "lock and key hypothesis" attempts to explain the mechanism of
1. vacuole formation
2. pinocytosis
3. sharing of electrons
4. enzyme specificity
Any substance that is acted upon by an enzyme is called a(n)
1. coenzyme
2. substrate
3. vitamin
4. polypeptide
An enzyme that hydrolyzes protein will not act upon starch. This fact is an indication that enzymes are
1. hydrolytic
2. specific
3. catalytic
4. synthetic
At about 0 C., most enzymes are
1. inactive
2. active
3. destroyed
4. replicated
Vitamins are essential to the survival of organisms because vitamins usually function as
1. substrates
2. nucleic acids
3. coenzymes
4. nucleotides
Which chemical is classified as an enzyme?
1. galactose
2. lipid
3. protease
4. manganese dioxide
Salivary amylase is an enzyme in humans that breaks down starch. The optimum pH for this reaction is 6.7. The rate of this reaction would not be affected by
1. maintaining the pH of the reaction at 6.7
2. substrate concentration
3. enzyme concentration
4. decreasing the temperature of the reaction by 5 degrees C
A certain enzyme will hydrolyze egg white but not starch. Which statement best explains this observation?
1. Starch molecules are too large to be hydrolyzed.
2. Enzyme molecules are specific in their actions.
3. Egg white acts as a coenzyme for hydrolysis
4. Starch is composed of amino acids.
Which environmental condition would most likely have the LEAST effect on the rate of enzyme controlled hydrolytic reactions in humans? (1.) (2.) (3.) (4.)
1. the pH of the solution
2. the temperature of the solution
3. the amount of enzyme present
4. the amount of light present
Which statement best expresses the information represented in the graph shown?
1. The action of enzymes varies with pH.
2. A pH of 7 provides the optimum
  environment for digestive enzymes
3. Gastric juice is active at a pH extending from 0 to 12.
4. Acids have a pH greater than 7.
Lipase, maltase, and protease are members of a group of catalysts known as
1. hormones
2. carbohydrates
3. lipids
4. enzymes
The effect of temperature on the relative rate of action of an enzyme is represented in the graph below.

The optimum temperature for the action of this enzyme is approximately
1. 15 C
2. 22 C
3. 37 C
4. 50 C
Here are of some stages of an enzyme-controlled reaction .

An enzyme-substrate complex is represented by diagram
1. A
2. B
3. C
4. D
The diagram below represents three steps in the hydrolysis of a molecule of sucrose.

In this diagram, structure X is most likely
1. a molecule of oxygen
2. the end product
3. an organic catalyst
4. the substrate
Which molecule is not associated with the reaction that is occurring in the solution
1. A
2. B
3. C
4. D
Which enzyme represents an enzyme functioning in this reaction?
1. A
2. B
3. C
4. D
The fact that amylase in the human small intestine works best at normal body temperature (37 degreess C) suggests that
1. amylase is denatured at temperatures below 37 degrees C
2. amylase can function only in the small intestine
3. the lock-and-key model of enzyme action does not apply to amylase
4. the optimum temperature for amylase is 37 degrees C
Hydrogen peroxide (H2O2) is a toxic by-product of cellular metabolism in aerobic organisms. The reaction shown occurs within the cells to prevent the accumulation of hydrogen peroxide.

In this reaction, catalase functions as an
1. indicator in the detection of hydrogen peroxide
2. emulsifier in the digestion of hydrogen peroxide
3. enzyme in the synthesis of hydrogen
  peroxide
4. enzyme in the breakdown of hydrogen peroxide
Which statement best describes the enzyme represented in the graphs below?
1. This enzyme works best at a temperature of 35 C and a pH of 8.
2. This enzyme works best at a temperature of 50 C and a pH of 12.
3. Temperature and pH have no influence on the activity of this enzyme.
4. This enzyme works best at a temperature above 50 C and a pH above 12
Use the chart below and your knowledge of enzymes to answer the question.

If enzyme C is functioning at 25°C and a pH of 7, under which conditions would the rate of enzyme action probably increase?
1. The temperature is decreased to 22 C and the pH is kept the same.
2. The temperature is kept the same and the pH is decreased to 6.
3. The temperature is increased to 44 C and the pH is kept the same.
4. The temperature is increased to 30 C and the pH is increased to 8.
Use the chart below and your knowledge of enzymes to answer the question.

At what temperature would enzyme D most likely be denatured?
1. 15 C
2. 20 C
3. 25 C
4. 39 C
Use the chart below and your knowledge of enzymes to answer the question.

Which enzyme would most likely be functional in bacteria living in a hot spring that is 35°C above normal human body temperature?
1. A
2. B
3. C
4. D
Which factor does not alter the rate of hydrolysis of maltose, a disaccharide?
1. temperature of the environment of the reaction
2. pH of the environment of the reaction
3. number of enzyme molecules present
4. size of the substrate molecule
Which statement is a valid conclusion based on the information in the graph below?
1. The maximum rate of human digestion occurs at about 45 C.
2. The maximum rate of human respiration occurs at about 57 C.
3. Growth can be controlled by enzyme action.
4. Temperature can influence the action of an enzyme.
A student placed groups of 50 seeds in a variety of temperatures ranging from 0 to 50 C. A difference in the rate of germination observed in the groups at different temperatures was most likely due to the effect of temperature on
1. ammonia
2. acids
3. enzymes
4. cellulose