Biology 1406 Professor Salazar
Bio 1 Test 2
Short Answer
Name ____________________Date ___________________
1. The movement of molecules across a cell membrane in which no energy is required (i.e.
diffusion) is called ________ transport and the movement of molecules across the membrane in
which energy (i.e. ATP) is required is called ________ transport.
Answer: passive; active
Diff: 2 Type: SA Section 5.2
Skill: Factual
2. Compare and contrast:
a. Facilitated diffusion/active transport
b. Osmosis/simple diffusion
Answer: Facilitated diffusion and active transport both require membrane transport proteins.
However, facilitated diffusion does not require energy and moves substances down a
concentration gradient. Active transport requires energy and moves substances against a
concentration gradient. Osmosis and simple diffusion are both passive processes. However,
osmosis refers to the movement of water down its concentration gradient across a
semipermeable membrane. No membrane is required for simple diffusion.
Diff: 2 Type: SA Section 5.2
Skill: Conceptual
3. Distinguish between the three types of endocytosis.
Answer: Pinocytosis is for fluid intake, receptor-mediated endocytosis is for the uptake of specific
molecules, and phagocytosis is used to uptake large particles into the cell.
Diff: 2 Type: SA Section 5.2
Skill: Factual
4. In plant cells, ________ allow for communication between cells and in animal cells the
________ serve the same purpose.
Answer: plasmodesmata; gap junctions
Diff: 2 Type: SA Section 5.3
Skill: Conceptual
5. In ________, membranes of adjacent cells are held together by proteins and carbohydrates,
much like glue.
Answer: desmosomes
Diff: 2 Type: SA Section 5.3
Skill: Factual
6. In plant cells, ________ allow for communication between cells and in animal cells the
________ serve the same purpose.
Answer: plasmodesmata; gap junctions
Diff: 2 Type: SA Section 5.3
Skill: Conceptual
7. ________ are biological catalysts.
Answer: Enzymes
Diff: 2 Type: SA Section: 6.4
Skill: Factual
8. Normally an enzyme has maximal enzyme activity at 37°C, but once it has been heated to
100°C and then cooled back down to 37°C the enzyme is no longer active. Why?
Answer: The enzyme's three-dimensional shape would have been distorted and the active site
was no longer able to bind the appropriate substrates in the reaction.
Diff: 3 Type: SA Section: 6.4
Skill: Conceptual
9. What is the role of the green pigment chlorophyll in photosynthesis?
Answer: Critical in light-dependent reactions to harness light energy and begin the flow of
electrons which in turn creates the proton gradient allowing for chemiosmosis¹ATP formation
which is required for the light-independent reactions.
10. In the process of photosynthesis, ________ and ________ are required from the light
dependent reactions to completely reduce carbon dioxide to glucose in the Calvin cycle.
Answer: ATP; NADPH
Diff: 2 Type: SA
Section: 7.2
Skill: Factual
11. During the light-dependent reactions of photosynthesis, the synthesis of ________ is coupled
to the diffusion of protons.
Answer: ATP
Diff: 2 Type: SA
Section: 7.2
Skill: Factual
12. The ________ is composed of a light-harvesting complex and an electron transport system.
Answer: photosystem
Diff: 1 Type: SA
Section: 7.2
Skill: Factual
13. Why is no glucose produced if a plant is kept for long periods in the dark, even though the
sugar producing reactions are called light-independent?
Answer: The light-independent reactions require ATP and NADPH produced from the lightdependent reactions to drive the synthesis of glucose in the Calvin cycle reactions.
Diff: 2 Type: SA
Section: 7.3
Skill: Conceptual
14. Is glucose a direct product of the Calvin-Benson cycle reactions?
Answer: No, G3P is the carbohydrate produced and two of these molecules must combine to
form one molecule of glucose.
Diff: 2 Type: SA
Section: 7.3
Skill: Conceptual
15. Photosystem II generates ________ and Photosystem I generates ________, both of which
are required by the light-dependent reactions.
Answer: ATP; NADPH
Diff: 2 Type: SA
Section: 7.4
Skill: Conceptual
16. How are the light-dependent and light-independent reactions related to one another?
Answer: The light-dependent reactions produce the ATP and NADPH required to drive the lightdependent reactions which results in the synthesis of sugar (glucose).
Diff: 2 Type: SA
Section: 7.4
Skill: Conceptual
17. In C3 plants, the Calvin cycle occurs in the chloroplasts of ________ cells, but in C 4 plants
the cycle occurs in the ________ cells.
Answer: mesophyll; bundle sheath
Diff: 2 Type: SA
Section: 7.5
Skill: Factual
18. Many plants have evolved leaves that have adjustable pores, called ________, which allow
for gas exchange and water loss.
Answer: stomata
Diff: 2 Type: SA
Section: 7.5
Skill: Factual
19. Why does photorespiration reduce photosynthesis efficiency?
Answer: Photorespiration does not produce any useful cellular energy and it prevents the
synthesis of glucose in C3 plants.
Diff: 2 Type: SA
Section: 7.5
Skill: Conceptual
20. What is photorespiration? Describe how C4 plants have evolved the ability to reduce
photorespiration.
Answer: Photorespiration occurs when RuBP combines with O 2 rather than CO2 not allowing the
plant to fix carbon and produce glucose. C4 plants use a two stage carbon-fixation pathway where
PEP is used instead of RuBP which specifically reacts with CO 2 and not O2¹the CO2 is then
shuttled to the bundle-sheath cells and creates a high CO2 concentration that favors the regular
C3 cycle reactions without competition from O2.
Diff: 3 Type: SA
Section: 7.5
Skill: Conceptual
21. Why is it important to regenerate NAD+ molecules during fermentation?
Answer: Glycolysis would stop when all the NAD+ molecules were used up resulting in no energy
production for that cell.
Diff: 2 Type: SA Section: 8.2
Skill: Conceptual
22. ________ is the only stage in glucose metabolism that does not require oxygen to proceed.
Answer: Glycolysis
Diff: 2 Type: SA Section: 8.2
Skill: Conceptual
23. Two possible end products of fermentation are ________ as is produced by our muscle cell
under anaerobic conditions and ________ by yeast under anaerobic conditions.
Answer: lactic acid; carbon dioxide and alcohol
Diff: 2 Type: SA Section: 8.2
Skill: Conceptual
24. Chemiosmosis links a hydrogen gradient to the production of ATP. True or False?
Answer: TRUE
Diff: 2 Type: TF Section: 8.3
Skill: Factual
25. Most of the ATP produced during cellular respiration is generated in the ________ after the
movement of hydrogen ions through ATP-synthesizing proteins in the inner membrane of the
mitochondrion.
Answer: mitochondrial matrix
Diff: 2 Type: SA Section: 8.3
Skill: Factual