5 Written questions
5 Matching questions
- 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.
- In the electron transport systems of chloroplasts and mitrochondria,
A. the system consists of a series of membrane bound carriers that transfer electrons from one carrier to another.
B. high energy electrons enter the system and low energy electrons exit the system.
C. energy release occurs when the electron transfers from one carrier to another.
D. All of the choices are correct.
If the reaction graphed at right is coupled with D→E, then D →E is:
D. none of the above
- Which best describes the second law of thermodynamics?
A. Energy is not created nor destroyed, but it can change into matter.
B. Energy is not created nor destroyed, but it can change from one energy form to another.
C. Energy can be created from matter or used to produce matter.
D. Some useful energy is lost as heat whenever an energy transfer occurs.
E. Energy transfers are always 100% efficient in changing energy from one useful form to another.
- An automobile engine is about 20 - 30% efficient in converting chemical energy to mechanical energy. Cells are about 39% efficient if the transformation of glucose to ATP. The rest of the energy is lost as heat. This is illustrative of the:
A. First Law of Thermodynamics.
B. Second Law of Thermodynamics.
C. Third Law of Thermodynamics.
D. The Cell Theory.
- a D. An enzyme's activity is generally reduced by an increase in substrate concentration.
- b B. endergonic
- c D. Some useful energy is lost as heat whenever an energy transfer occurs.
- d D. All of the choices are correct.
- e B. Second Law of Thermodynamics.
5 Multiple choice questions
- A. the cellular energy expended in "thinking" must be less than the chemical bond energy supplied in food to these brain cells.
- A. ADP and phosphate.
- C. Eventually sunlight that is absorbed on the earth returns to space as dispersed heat.
5 True/False questions
The energy for ATP synthesis in chemiosmotic phosphorylation comes from the movement of hydrogen ions across a membrane down a concentration gradient.
True False → True
__________ 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 → C. A; E and F
The activity of an enzyme might be increased by all of the following except ________?
A. increase in substrate concentration.
B. a vitamin.
C. 2-4 degree increase in temperature.
D. lead. → D. lead.
From the above table of free energy exchange, it is obvious that
A. photosynthesis and cellular respiration have essentially the same amount of free energy generated or released.
B. free energy is released in all of these reactions except photosynthesis.
C. where the free energy is negative, formation of the products is more likely.
D. All of the choices are true.
E. None of the choices are true. → B. endergonic
A coenzyme is
A. an ionic cofactor that interacts with an enzyme to allow it to work.
B. a protein cofactor that interacts with an enzyme to allow it to work.
C. a nonprotein organic cofactor that interacts with an enzyme to allow it to work.
D. an ionic cofactor that interacts with an enzyme to inhibit it.
E. a protein cofactor that interacts with an enzyme to inhibit it. → E. Both taking lactase enzyme and avoiding all dairy products would be correct.