5 Written questions
5 Matching questions
- ATP is considered to be
A. an enzyme used widely in all kinds of cells.
B. a coenzyme used to inhibit or activate different enzymes.
C. a molecule that carries a great deal of chemical energy in a chemical bond.
D. the precursor of a high-energy membrane-bounded protein.
In this pathway, B C is coupled with ADP ATP. Categorize the reactions as endergonic or exergonic.
A. B C is endergonic and ADP ATP is exergonic.
B. ADP ATP is endergonic and B C is exergonic.
C. Both B C and ADP ATP are endergonic.
D. Both B C and ADP ATP are exergonic.
__________ represents the first reactant of this metabolic pathway and ________ reperesents the endproduct (s) of the pathway?
A. A; E
B. B; E and F
C. A; E and F
D. A and B; D and E
- While science is not yet able to describe the phenomenon of "thinking" in physical terms, we can be certain that it is a process involving the metabolism of brain cells. With positron emission tomography (PET scan) it is possible to inject short-lived isotopes and image the regions of the brain that have the most active metabolism during various mental activities. For different mental functions, different regions and amounts of nerve cells become active. However,
A. the cellular energy expended in "thinking" must be less than the chemical bond energy supplied in food to these brain cells.
B. "thought" cannot be linked to cell processes because energy is not related to matter.
C. since thoughts can occur over and over, the requirement for a continual input of energy to prevent entropy does not apply to this cell activity.
D. "thinking" is beyond the scope of science to study.
- Which of the following is consistent with the laws of physics governing energy?
A. When a liter of gasoline is burned in a car engine, 100% of its energy goes into moving the car along the road.
B. You eat a "quarter-pounder" hamburger and assemble exactly a quarter-pound of additional body weight on your body.
C. Eventually sunlight that is absorbed on the earth returns to space as dispersed heat.
D. A calorie of sunlight becomes a calorie of plant tissue that, eaten by you, becomes a calorie of heat lost in muscle "power."
E. Chemical bonds are a case of converting energy to matter; breaking the bonds converts matter to energy.
- a C. a molecule that carries a great deal of chemical energy in a chemical bond.
- b B. ADP ATP is endergonic and B C is exergonic.
- c C. Eventually sunlight that is absorbed on the earth returns to space as dispersed heat.
- d A. the cellular energy expended in "thinking" must be less than the chemical bond energy supplied in food to these brain cells.
- e C. A; E and F
5 Multiple choice questions
- D. All of the choices are true.
- B. The reaction will continue, since the enzyme is not consumed by the reaction.
- E. All of the statements are true.
- B. Mitochondria and chloroplasts.
- D. The chemical compounds in cells lose their organization over time because there is no longer an input of energy to maintain the organized state.
5 True/False questions
Coupling occurs when the energy released by an exergonic reaction is:
A. used to drive another exergonic reaction.
B. used to drive an endergonic reaction.
C. lost as nonusable heat to the environment.
D. used to decrease the entropy of the universe.
E. All of the choices are correct. → D. All of the choices are correct.
Astrophysicists explain that eventually the sun will swell to become a red giant, engulf the earth and "burn out" with all forms of energy dispersing in a final "heat death." Compared with conditions today, the entropy of the universe then will
A. have increased greatly.
B. have decreased greatly.
C. remain the same because energy cannot be created or destroyed. → True
Which statement is NOT true about the effects of various conditions on the activity of an enzyme?
A. Higher temperatures generally increase the activity of an enzyme up to a point.
B. Above a certain range of temperatures, the protein of an enzyme is denatured.
C. A change in pH can cause an enzyme to be inactivated.
D. An enzyme's activity is generally reduced by an increase in substrate concentration.
E. When sufficient substrate is available, the active site will nearly always be occupied. → E. All of the statements are true.
The metabolic pathway at right involves how many possible chemical reactions?
D. three → A. five
Of the following, which process will not denature a protein?
A. heating to temperatures above 100 C
B. addition of strong acids or strong bases
D. addition of distilled water → C. a muscle contracting