Biology 1001 Spring 2017 Ch. 7
24) Light reactions produce: A) ATP, NADPH, and O2. B) ATP, NADPH, and CO2. C) glucose, ATP, and O2. D) glucose, ATP, and CO2. E) ATP, NADPH, and H2O.
A
40) Which of the following provides O2 as an end product? A) light reaction B) light-independent reaction C) cellular respiration D) glycolysis E) synthesis
A
13) Energy is passed around different chlorophyll molecules until it reaches a specific chlorophyll molecule called the: A) reaction center. B) photoelectric point. C) electron carrier molecule. D) accessory pigment. E) nucleus.
A
26) During the process of photosynthesis, solar energy is converted to: A) chemical energy. B) heat energy. C) thermal energy. D) mechanical energy. E) nuclear energy.
A
3) What structural feature of a leaf enables it to obtain CO2 from the air? A) stomata B) epidermis C) cuticle D) mesophyll E) chloroplast
A
33) Which process of photosynthesis is linked to the production of ATP? A) photosystem II B) generation of NADPH C) splitting of a water molecule D) fixing of carbon E) synthesis of O2
A
53) Water is required to drive which of the following reactions? A) the light reactions only B) the Calvin cycle only C) both the light reactions and the Calvin cycle D) neither the light reactions nor the Calvin cycle
A
54) NADPH is synthesized during which of the following reactions? A) the light reactions only B) the Calvin cycle only C) both the light reactions and the Calvin cycle D) neither the light reactions nor the Calvin cycle
A
59) What kind of habitat does a C4pathway plant favor? A) hot and dry B) cool and moist C) totally aquatic D) wet and cloudy E) cool and dry
A
64) In C3 photosynthesis, what fixes the carbon? A) RuBP B) PEP C) PGA D) PGAL E) ATP
A
9) Imagine that a scientist discovers a mutant plant seedling that appears to lack stomata. What would be the effect of this? A) CO2 would not be able to enter the plant as a reactant for photosynthesis. B) Water would not be able to enter the plant cells. C) Visible wavelengths of light would be unable to reach the chloroplasts. D) Additional ATP would be produced by the seedling, and the plant would grow taller.
A
7) During the light reactions of photosynthesis, the synthesis of ________ is coupled to the diffusion of protons.
ATP
9) What happens to the photosynthetic reactions when no sunlight is present?
ATP and NADPH levels from the light reactions become limiting, and that in turn can lead to a decrease in sugar production following the Calvin cycle.
10) Photosystem II generates ________, and photosystem I generates ________, both of which are required by the light reactions.
ATP; NADPH
6) In the process of photosynthesis, ________ and ________ are required from the light reactions to completely reduce carbon dioxide to glucose.
ATP; NADPH
20) The replacement electrons for the reaction center of photosystem II come from: A) photosystem I. B) H2O. C) glucose. D) O2. E) NADPH.
B
28) The role of water in photosynthesis is to: A) maintain turgor pressure. B) provide electrons. C) provide oxygen. D) provide H2.
B
11) Albino corn has no chlorophyll. You would expect albino corn seedlings to: A) capture light energy in the white end of the visible light spectrum. B) fail to thrive because they cannot capture light energy. C) synthesize glucose indefinitely, using stored ATP and NADPH. D) switch from the C4 pathway to the CAM pathway. E) use accessory pigments such as carotenoids to capture light.
B
23) What is produced in the electron transport system associated with photosystem II? A) NADPH B) ATP C) glucose D) O2 E) CO2
B
25) Where does the O2 released during photosynthesis come from? A) CO2 B) H2O C) ATP D) C6H12O6 E) RuBP
B
38) The primary function of the light reactions of photosynthesis is to: A) produce energy-rich glucose from carbon dioxide and water. B) produce energy-rich ATP and NADPH. C) produce NADPH used in respiration. D) convert light energy to the chemical energy of lipids. E) use ATP to make glucose.
B
39) You are carrying out an experiment on several aquatic plants in your fish tank. You decide to expose two of the plants to green light and two to blue light. You want to determine which type of light is best for the light reactions, so you decide to record the amount of oxygen bubbles produced to reach your conclusions. Which of the following results would be expected? A) There would be more bubbles from the plants in green light than from those in blue light. B) There would be more bubbles from the plants in blue light than from those in green light. C) There would be the same number of bubbles from plants in blue or green light. D) No bubbles would be produced in either green light or blue light.
B
41) Glucose synthesis during photosynthesis requires that: A) sunlight must be present. B) the products of energy-capturing reactions must be available. C) the concentration of O2 must be significantly higher than that of CO2. D) mitochondria must convert light energy to ATP.
B
43) Where is glucose synthesized during photosynthesis? A) thylakoids B) cytoplasm C) matrix D) stroma E) stoma
B
45) Which of the following occurs during the Calvin cycle of photosynthesis? A) Water is converted to its most basic elements, hydrogen and water. B) Carbon dioxide is converted to chemicals that can be used to make sugars. C) Chlorophyll acts as an enzyme, but only in the dark. D) Nothing occurs because the plant rests in the dark.
B
5) Specifically, molecules of chlorophyll are located in the membranes of sacs called: A) stoma. B) thylakoids. C) stroma. D) grana. E) vesicles.
B
50) During photosynthesis, when is CO2 utilized? A) during the light reactions only B) during the Calvin cycle only C) during both the light reactions and the Calvin cycle D) during neither the light reactions nor the Calvin cycle
B
51) ATP is required during which of the following reactions? A) the light reactions only B) the Calvin cycle only C) both the light reactions and the Calvin cycle D) neither the light reactions nor the Calvin cycle
B
63) C3 plants are adapted to ________ environmental conditions, whereas C4 plants are adapted to ________ conditions. A) dry; wet B) wet; dry C) temperate; cool and rainy D) high-light; low-light E) drought; rainy
B
12) The energy source in photosynthesis is: A) glucose. B) ultraviolet light. C) visible light. D) air. E) oxygen.
C
44) What is the correct order for the reactions of the Calvin cycle? A) carbon fixation, regeneration of RuBP, synthesis of G3P B) synthesis of G3P, regeneration of RuBP, carbon fixation C) carbon fixation, synthesis of G3P, regeneration of RuBP D) regeneration of RuBP, carbon fixation, synthesis of G3P E) synthesis of G3P, carbon fixation, regeneration of RuBP
C
52) Enzymes are required during which of the following reactions? A) the light reactions only B) the Calvin cycle only C) both the light reactions and the Calvin cycle D) neither the light reactions nor the Calvin cycle
C
8) The cellular organelle that is responsible for photosynthetic activity is the: A) nucleus. B) mitochondrion. C) chloroplast. D) endoplasmic reticulum. E) ribosome.
C
1) Before photosynthesis evolved, ________ was rare in Earth's atmosphere. A) N2 B) CO2 C) O2 D) H2O E) air
C
10) Imagine that a plant in your garden doesn't receive an adequate amount of water. Which of the following would be most affected by this? A) the light reactions of photosynthesis only B) the Calvin cycle of photosynthesis only C) both the light reactions and the Calvin cycle of photosynthesis D) neither the light reactions nor the Calvin cycle of photosynthesis
C
14) Carotenoid pigments are found in the: A) mitochondria. B) stroma of the chloroplasts. C) thylakoid membranes of the chloroplasts. D) nucleus.
C
19) Which statement is TRUE regarding the light reactions? A) They rely on energy provided by glucose synthesis. B) Oxygen is required. C) Without water, the system would shut down. D) ATP and NADPH are needed. E) Without photosystem I, photosystem II could not occur.
C
21) Which sequence accurately describes the flow of electrons in photosynthesis? A) photosystem I → photosystem II → H2O → NADP B) photosystem II → photosystem I → NADP → H2O C) H2O → photosystem II → photosystem I → NADP D) photosystem I → photosystem II → NADP → H2O E) H2O → photosystem I → photosystem II → NADP
C
27) The light reactions of photosynthesis result in which of the following? A) oxidation of CO2 B) reduction of H2O C) synthesis of ADP D) oxidation of chlorophyll E) oxidation of glucose
C
30) Hydrogen ions cross the thylakoid membranes from the stroma by: A) osmosis. B) facilitated diffusion. C) active transport. D) simple diffusion. E) synthesis.
C
34) Suppose you are studying photosynthesis in a research lab. You grow your plants in a chamber with a source of water that has a radioactively labeled oxygen atom. What photosynthetic product will be radioactive? A) ATP B) glucose C) O2 gas D) NADPH E) CO2 gas
C
35) Which of the following statements is TRUE about the light reactions? A) NADPH and ATP are both synthesized from the light reactions within photosystem I. B) Photosystem I generates ATP, while photosystem II generates NADPH. C) Photosystem II generates ATP, while photosystem I generates NADPH. D) ATP is the final electron acceptor.
C
37) The NADPH required for carbon dioxide fixation is formed: A) by the reduction of oxygen. B) by the hydrolysis of ATP. C) during the light reactions. D) only in C4 plants. E) in the mitochondria.
C
42) The term "cycle" is used to describe the Calvin cycle because: A) the same reactions occur every time. B) CO2 is fixed. C) the process begins and ends with RuBP. D) glucose is synthesized during the process. E) the process depends on products from the light reactions.
C
46) All of the following are part of the Calvin cycle EXCEPT: A) carbon fixation. B) synthesis of G3P. C) generation of ATP. D) regeneration of RuBP.
C
47) What happens to CO2 when it moves into the stroma? A) The CO2 gives up its O2. B) It immediately passes on to the thylakoids. C) It becomes a carbohydrate. D) The CO2 becomes a by-product of cellular respiration. E) It is converted to water.
C
55) In the C3 pathway, where does the carbon come from to form glucose? A) ATP and NADPH B) chlorophyll C) atmospheric CO2 D) enzymes E) water
C
62) If C4 photosynthesis prevents photorespiration, why haven't all plants evolved to use the C4 pathway? A) All plants will evolve to be C4 in time. B) C4 produces some toxic by-products. C) C4 is not advantageous in all climates. D) Only some plants use C4 photosynthesis. E) C4 is advantageous in only high-oxygen habitats.
C
12) Some plants, called the ________ plants, have evolved a way to reduce photorespiration.
C4
2) Explain how the leaf is adapted for capturing energy from sunlight and for acquiring carbon dioxide and water.
CO2 comes through adjustable pores, or stomata, and water comes from the vascular bundles (or veins) to the mesophyll cells. Leaves are broad and flat to provide a large surface area to the sun. Chlorophyll molecules embedded in the thylakoid membrane of the chloroplast absorb sunlight.
5) ________ is the main light-capturing molecule in chloroplasts and is responsible for giving most leaves their characteristic green color.
Chlorophyll
3) What is the role of the green pigment chlorophyll in photosynthesis?
Chlorophyll is critical in light reactions to harness light energy and begin the flow of electrons, which in turn creates the proton gradient allowing for ATP formation, which is required for the Calvin cycle.
36) Which of the following statements about the light reactions of photosynthesis is FALSE? A) The splitting of water molecules provides a source of electrons. B) Chlorophyll (and other pigments) absorbs light energy, which excites electrons. C) An electron transport chain is used to create a proton gradient. D) The proton (H+) gradient is used to reduce NADP. E) ATP is synthesized.
D
15) The pigment(s) that absorb light energy to drive photosynthesis is/are: A) chlorophyll only. B) carotenoids only. C) anthocyanins only. D) chlorophyll and carotenoids. E) carotenoids and anthocyanins.
D
17) Which of the following is NOT true of chlorophyll? A) It is green in reflected color. B) It absorbs light at the red and blue ends of the spectrum. C) It is the main photosynthetic pigment in plants. D) It is found in mitochondria. E) It does not absorb green wavelengths of light.
D
31) The energy of the movement of electrons down a concentration gradient via electron transport within chloroplasts and mitochondria is used to generate molecules of: A) H2O. B) CO2. C) glucose. D) ATP. E) O2.
D
49) Glucose is made during which of the following reactions? A) the light reactions only B) the Calvin cycle only C) both the light reactions and the Calvin cycle D) neither the light reactions nor the Calvin cycle
D
57) Where do the reactions of a C4 pathway occur in a plant such as corn? A) mesophyll cells only B) bundle sheath cells only C) epidermal cells only D) mesophyll and bundle sheath cells E) bundle sheath and epidermal cells
D
58) In the C4 pathway, what is the source of carbon? A) NADPH B) glucose C) water D) carbon dioxide E) ATP
D
61) Where does the C4 cycle get its name? A) Only four carbons are used in the cycle. B) It is a four-step process. C) Four CO2 molecules are released. D) The first product in the cycle has four carbons. E) PEP is a four-carbon molecule.
D
7) All of the following compounds are necessary constituents for photosynthesis EXCEPT: A) ATP. B) NADP. C) water. D) oxygen. E) carbon dioxide.
D
16) A pigment that absorbs red and blue light and reflects green light is: A) phycocyanin. B) carotenoid. C) xanthophyll. D) melanin. E) chlorophyll.
E
32) The energy of the movement of electrons down a concentration gradient via electron transport within the thylakoid membrane is used to generate: A) H2O. B) CO2. C) glucose. D) O2. E) ATP.
E
4) The vast majority of chloroplasts found in a leaf are in the: A) vascular bundles. B) cuticle. C) epidermis. D) stroma. E) mesophyll.
E
48) In green plants, the primary function of the Calvin cycle is to: A) use ATP to release carbon dioxide. B) use NADPH to release carbon dioxide. C) split water and release oxygen. D) transport glucose out of the chloroplast. E) construct the building blocks of simple sugars from carbon dioxide.
E
56) In the reduction of CO2 during C4 photosynthesis, which of the following initially combines with CO2? A) PGA B) RuBP C) PGAL D) NADH E) PEP
E
60) Photorespiration is detrimental for a plant because: A) O2 is required. B) CO2 is synthesized. C) RuBP is degraded. D) glucose is synthesized. E) no ATP is produced.
E
18) Suppose that you are experimenting with different types of lighting for your indoor green plants. Which of the following colors of light will be most effective? A) green B) orange-yellow C) blue D) red-green E) red-blue
E
2) The products of photosynthesis are: A) glucose and water. B) carbon dioxide, water, and energy. C) glucose and carbon dioxide. D) carbon dioxide, chlorophyll, and oxygen. E) glucose and oxygen.
E
22) The ATP and NADPH synthesized during the light reactions are: A) dissolved in the cytoplasm. B) transported to the mitochondria. C) pumped into a compartment within the thylakoid membrane. D) transported into the nucleus. E) dissolved in the stroma.
E
29) Which of the following is a source of electrons that green plants use for reduction reactions? A) glucose B) CO2 C) RuBP D) O2 E) H2O
E
6) All of the following factors influence the rate of photosynthesis EXCEPT: A) light intensity. B) temperature. C) atmospheric CO2 levels. D) water availability. E) atmospheric N2 levels.
E
65) In C4 photosynthesis, where does the carbon in newly synthesized glucose come from? A) ATP and NADPH B) chlorophyll C) enzymes D) water E) atmospheric CO2
E
4) Carbon dioxide is required in the light reactions of photosynthesis. True or False?
FALSE
1) The stacked thylakoids are disk-shaped, interconnected membranous sacs embedded in the stroma. True or False?
FALSE
5) Imagine you are conducting a photosynthesis experiment on a plant in the lab. You block any light from reaching the plant. Explain the specific effect this will have on the light reactions.
Light will not be present to hit the chlorophyll and electrons will not be excited. Therefore, the light reactions will not occur and no energy will be produced to be used in the dark reactions.
6) Is glucose a direct product of the Calvin cycle?
No; G3P is the carbohydrate produced, and two of these molecules must combine to form one molecule of glucose.
10) Why does photorespiration reduce photosynthesis efficiency?
Photorespiration does not produce any useful cellular energy, and it prevents the synthesis of glucose in C3 plants.
11) What is photorespiration? Describe how C4 plants have evolved the ability to reduce photorespiration.
Photorespiration occurs when RuBP combines with O2 rather than CO2, so the plant is not allowed 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 CO2 and not O2. The 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.
2) The majority of the leaf's chloroplasts are found in the mesophyll cells. True or False?
TRUE
3) The photosystems are involved in the light reactions of photosynthesis. True or False?
TRUE
5) The carotenoids and other accessory pigments in the chloroplast help capture light into the reaction center chlorophyll molecules. True or False?
TRUE
6) Under dry conditions, a C4 plant is more photosynthetically efficient than a C3 plant. True or False?
TRUE
7) Which component of the Calvin cycle is recycled and why is this important for the Calvin cycle?
The RuBP molecule is recycled. This is essential to maintain the cyclical nature of the process.
1) Give the simplest chemical equation for photosynthesis. For each reactant, indicate where the plant acquires it. For each product, note during what part of photosynthesis it is produced.
The chemical equation for photosynthesis is 6 CO2 + 6 H2O + light energy → C6H12O6 + 6 O2 CO2 comes through the stomata, water comes from the vascular bundles (or veins) to the mesophyll cells, and chlorophyll molecules embedded in the thylakoid membrane of the chloroplast absorb sunlight. The glucose is produced immediately following the Calvin cycle, and the oxygen is produced during the light reactions.
8) How are the light reactions and the Calvin cycle related to each other?
The light reactions produce the ATP and NADPH required to drive the Calvin cycle, which results in the synthesis of sugar (glucose).
4) Describe the two major components of a photosystem. What is the function of each?
The light-harvesting complex absorbs light and passes the energy to a specific chlorophyll molecule called the reaction center. The electron transport system is a series of electron carrier molecules that are responsible for directly donating electrons to the electron carrier molecule NADP+ and indirectly driving the synthesis of ATP.
8) Light-harvesting pigments in the chloroplast include chlorophyll and the accessory pigments called ________.
carotenoids
3) The process of photosynthesis converts solar energy to ________ energy stored in the bonds of glucose.
chemical
2) The cells in the ________ layer of the leaf contain the majority of a leaf's chloroplasts.
mesophyll
14) In C3 plants, the Calvin cycle occurs in the chloroplasts of ________ cells, but in C4 plants, the Calvin cycle occurs in the ________ cells.
mesophyll; bundle sheath
11) During the Calvin cycle, the combination of oxygen with RuBP rather than carbon dioxide is called ________.
photorespiration
13) During the process of ________, RuBP combines with oxygen instead of carbon dioxide.
photorespiration
9) A(n) ________ is composed of a light-harvesting complex and an electron transport system.
photosystem
4) Many plants have evolved leaves that have adjustable pores, called ________, which allow for gas exchange and water loss.
stomata
1) Light reactions occur in the ________, and the Calvin cycle occurs in the ________ of the chloroplast of a typical mesophyll leaf cell.
thylakoids; stroma
