MasteringBiology: Photosynthesis

True or false. Guard cells open during the day to allow gases to flow through the stomata. a. True b. False

a. True

The light reactions of photosynthesis include _____. a. reduction of NADP+ b. NADPH recycling c. the stoma d. reduction of CO2 e. the Calvin cycle

a. reduction of NADP+

The light reactions of photosynthesis use _____ and produce _____. a. water ... NADPH b. carbon dioxide ... oxygen c. carbon dioxide ... sugar d. NADPH ... NADP+ e. NADPH ... oxygen

a. water ... NADPH

What two molecules are produced by the light reactions and used to power the Calvin cycle? a. CO2 and O2 b. ATP and NADPH c. C6H12O6 and O2 d. C6H12O6 and RuBP e. G3P and H2O

b. ATP and NADPH

Can you tell from these absorption spectra whether red light is effective in driving photosynthesis? a. Because the absorption spectra of the pigments are highest in the purple/blue wavelengths, we can assume that red light is not effective. b. One cannot tell from this graph, but because chlorophyll a does absorb red light, we can predict that it would be effective in driving photosynthesis. c. These absorption spectra indicate that green and yellow wavelengths of light are much more effective than red light.

b. One cannot tell from this graph, but because chlorophyll a does absorb red light, we can predict that it would be effective in driving photosynthesis.

If only chlorophyll a were involved in the light reactions, would blue light (wavelength about 490 nm) be effective in driving photosynthesis? a. The peak absorption for chlorophyll b is close to this wavelength, so we can predict that blue light would be effective. b. The graph indicates that chlorophyll a absorbs very little blue light, so we can predict that blue light would not be effective. c. One cannot tell from this graph.

b. The graph indicates that chlorophyll a absorbs very little blue light, so we can predict that blue light would not be effective.

The primary function of light absorption by photosystems I and II is to produce _____. a. fluorescence b. a free, energized electron c. heat d. oxygen

b. a free, energized electron

The Calvin cycle describes the conversion of ___. a. water to carbon dioxide b. carbon dioxide to carbohydrates c. carbon dioxide to amino acids d. carbohydrates to proteins

b. carbon dioxide to carbohydrates

The conversion of NADP+ to NADPH occurs with the assistance of _____. a. electrons from carbon dioxide and energy from sunlight b. electrons from water and energy from sunlight c. electrons from water and energy from ATP d. electrons from carbon dioxide and energy from ATP

b. electrons from water and energy from sunlight

Which of the following equations represents photosynthesis? a. 6H2O + 6O2 → C6H12O6 + 6CO2 b. C6H12O6 + 6O2 → 6CO2 + 6H2O c. 6CO2 + 6H2O → C6H12O6 + 6O2 d. 6CO2 + 6O2 → C6H12O6 + 6H2O e. C6H12O6 + 6CO2 → 6O2 + 6H2O

c. 6CO2 + 6H2O → C6H12O6 + 6O2

What connects the two photosystems in the light reactions? a. Chlorophyll b. A chain of glucose molecules c. An electron transport chain d. A thylakoid e. The Calvin cycle

c. An electron transport chain

In which of the following organelles does photosynthesis take place? a. Ribosome b. Nucleus c. Chloroplast d. Central vacuole e. Mitochondrion

c. Chloroplast

What transports electrons from the light reactions to the Calvin cycle? a. NADH b. Chlorophyll c. NADPH d. An electron transport chain e. FADH2

c. NADPH

An action spectrum plots the rate of photosynthesis at various wavelengths of visible light, and it shows that blue light with a wavelength of about 490 nm is effective in driving photosynthesis. Based on this information and the absorption spectra shown at left, what role may chlorophyll b and carotenoids play in photosynthesis? a. Because chlorophyll a is found in the reaction-center complexes of both photosystems II and I, we can assume that these other pigments play no role in photosynthesis. b. These pigments probably play only a photoprotective role (absorbing excess light energy that could damage chlorophyll a) and a role in producing the colors of fall foliage. c. These pigments are able to absorb more wavelengths of light (and thus more energy) than chlorophyll a alone can absorb. As part of light-harvesting complexes in photosystems, they broaden the range of light that can be used in the light reactions.

c. These pigments are able to absorb more wavelengths of light (and thus more energy) than chlorophyll a alone can absorb. As part of light-harvesting complexes in photosystems, they broaden the range of light that can be used in the light reactions.

Which of the following colors of light are useful during the process of photosynthesis? a. blue, green, and orange b. green, orange, and red c. blue, red, and violet e. orange, red, and violet

c. blue, red, and violet

The radioactive isotope used in the Calvin experiments was ____. a. nitrogen-15 b. boron-8 c. carbon-14 d. carbon-12

c. carbon-14

Paper chromatography is used to _____. a. detect radioactivity b. force photosynthesis to occur c. separate components in a material of interest d. produce glucose

c. separate components in a material of interest

Chlorophyll is found in the _____ of chloroplasts. a. stroma b. outer membrane c. thylakoid membranes d. thylakoid space

c. thylakoid membranes

The light reactions take place in the _________ and the Calvin cycle takes place in the _________. a. inner membrane; outer membrane b. chloroplasts; mitochondria c. thylakoids; stroma d. stroma; thylakoids e. mitochondria; chloroplasts

c. thylakoids; stroma

Part A In simple summary form, the input of the Calvin cycle for every product is _____, and the output is _____ used for glucose synthesis. a. ADP ... ATP b. NADP+ ... NADPH c. 6 CO2 ... glucose d. 3 CO2 ... a three-carbon molecule

d. 3 CO2 ... a three-carbon molecule

Oxygen is the final electron acceptor for cellular respiration. What is the final electron acceptor in photosynthesis? a. light b. water c. ATP d. NADP+

d. NADP+

Which of the following structures allows for gas exchange between the tissues of a leaf and the atmosphere? a. Vascular bundle b. Epidermis c. Cuticle d. Stomata

d. Stomata

What type of organism was used in Calvin's experiments? a. diatoms b. pea plants c. bacteria d. algae

d. algae

Which gas contributes to both global warming and the deterioration of the ozone layer? a. CFCs b. oxygen c. methane d. carbon dioxide

a. CFCs

Which statement regarding the light reactions is true? a. Electrons are supplied to chlorophyll P680 as it reduces the primary electron acceptor. b. Glucose is a product of the light reactions. c. ATP synthesis occurs as electrons "fall" down the electron transport chain. d. Photoexcited electrons pass from photosystem I to photosystem II.

a. Electrons are supplied to chlorophyll P680 as it reduces the primary electron acceptor.

What provides electrons for the light reactions? a. H2O b. The Calvin cycle c. Light d. CO2 e. O2

a. H2O

Which of the following leaf types would be the most efficient at absorbing sunlight? a. Large, broad leaves b. Needlelike leaves c. All of these leaf types are equally efficient at absorbing sunlight. d. Small, narrow leaves

a. Large, broad leaves

You obtain the pigments called carotenoids in your diet when you eat carrots. Why do carotenoids appear yellow and orange? a. They absorb blue/green light and reflect yellow and red wavelengths of light. b. One cannot tell from this graph. c. They absorb yellow and orange wavelengths best. d. Their line on this absorption spectrum is colored orange.

a. They absorb blue/green light and reflect yellow and red wavelengths of light.

How many turns of the Calvin cycle are required to produce one molecule of glucose? a. one b. two c. six d. three

b. two

Which of the following are photoautotrophs? a. bacteria found in the human digestive tract d. deep-sea vent organisms that make organic molecules using hydrogen sulfide as an energy source c. filamentous molds growing on bread d. corn stalks just before harvest

d. corn stalks just before harvest

Which of these equations best summarizes photosynthesis? a. C6H12O6 + 6 O2 → 6 CO2 + 6 H2O + Energy b. 6 CO2 + 6 O2 → C6H12O6 + 6 H2O c. H2O → 2 H+ + 1/2 O2 + 2e- d. C6H12O6 + 6 O2 → 6 CO2 + 12 H2O e. 6 CO2 + 6 H2O → C6H12O6 + 6 O2

e. 6 CO2 + 6 H2O → C6H12O6 + 6 O2

What provides the carbon atoms that are incorporated into sugar molecules in the Calvin cycle? a. G3P (C3H6O3) b. Glucose (C6H12O6) c. Sucrose (C12H22O11) d. RuBP e. Carbon dioxide (CO2)

e. Carbon dioxide (CO2)

_____ has a longer wavelength than _____. a. Green ... yellow b. Yellow ... red c. Violet ... blue d. Blue ... green e. Red ... green

e. Red ... green