ch 10 questions

photosystem I

Energized electrons from ____ enter an electron transport chain and are then used to reduce NADP+.

photorespiration

In C3 plants the conservation of water promotes _____.

cytoplasm

In C4 and CAM plants carbon dioxide is fixed in the _____ of mesophyll cells.

oxygen

What important molecule that is needed for cellular respiration is released when water is split in the light reactions of photosynthesis?

B (All organisms use the sugars produced by photosynthesis to generate energy.)

What is the biological significance of the light-independent reactions of photosynthesis? A) They make oxygen. B) They convert carbon dioxide to sugar. C) They convert ATP to sugar. D) They generate ATP and NADPH.

A (CO2 is unusable until plants have "fixed" this carbon into sugar.)

What is the importance of the light-independent reactions in terms of carbon flow in the biosphere? A) The light-independent reactions turn CO2, a gas, into usable carbon in the form of sugars. B) The light-independent reactions turn glucose, a sugar, into CO2 gas. C) The light-independent reactions turn sugar into ATP for energy. D) The light-independent reactions use CO2 to make ATP.

NADPH

Which of molecule is the primary product of photosystem I?

protons (The channels formed by ATP synthase are specific for protons.)

Which of the following particles can pass through the ATP synthase channel? -ADP -Protons -Inorganic phosphate -ATP

A (The regeneration of RuBP ensures that the Calvin cycle can proceed indefinitely, since RuBP fixes carbon dioxide into an organic molecule that is used to produce sugar.)

Which of the following reactions ensures that the Calvin cycle can make a continuous supply of glucose? A) Regneration of RuBP B) Production of 3-phosphoglycerate C) Production of G3P D) Carbon fixation

photosystems I and II

chlorophyll can be found in...

stroma

where does the Calvin Cycle occur?

photosynthesis (Oxygen is a by-product of the photosynthetic process.)

which process produces oxygen? -cellular respiration -photosynthesis

photophosphorylation

ATP production resulting from the capture of light energy by chlorophyll

PS II → pheophytin → plastoquinone → cytochrome complex → plastocyanin → PS I → ferredoxin

According to the Z scheme, what is the path of electrons through photosystem I (PS I) and photosystem II (PS II)? (7 places)

proton gradient

According to the chemiosmotic hypothesis, what provides the energy that directly drives ATP synthesis?

pigments

molecules that absorb only certain wavelengths of light energy from the sun in order to begin the photosynthetic reactions

ATP synthase

phosphorylates ADP to make ATP

electron transport chain (The energy released as electrons are passed along the electron transport chain is used to pump protons into the thylakoid compartment.)

releases energy that is used to pump hydrogen ions from the stroma into the thylakoid compartment

photosystem II

splits water into 1/2 O2, H+, and e-

water; NADPH

the light reactions of photosynthesis use ____ and produce ____

D (In C3 and CAM plants carbon dioxide fixation and the Calvin cycle occur in the same cells.)

C4 plants differ from C3 and CAM plants in that C4 plants _____. A) use malic acid to transfer carbon dioxide to the Calvin cycle B) are better adapted to wet conditions C) use PEP carboxylase to fix carbon dioxide D) transfer fixed carbon dioxide to cells in which the Calvin cycle occurs E) open their stomata only at night

D Reaction center chlorophylls are the only chlorophylls that donate electrons to an electron acceptor.

Chlorophyll molecules donate electrons to an electron acceptor ____. A) in the antenna complex B) when fluorescence occurs C) at night D) in the reaction center

D (although the proton gradient is present, ADP and inorganic phosphate are required to make ATP and were not added to the reaction.)

Chloroplast membrane vesicles are equilibrated in a simple solution of pH 5‎ . The solution is then adjusted to pH 8‎ . Which of the following conclusions can be drawn from these experimental conditions? A) Protons will not diffuse toward the outside of the vesicles. B) ATP will be produced because the proton gradient favors proton movement through the ATP synthase channels. C) The change in the solution's pH results in a gradient across the chloroplast membranes such that there is a lower concentration of protons inside the vesicles and a higher concentration outside. D) ATP will not be produced because there is no ADP and inorganic phosphate in the solution.

A Sugars are produced as a result of photosynthesis.

During photosynthesis, the light energy from the sun is captured and stored in the bonds of _____. A) sugars B) hemoglobin C) oxygen D) water

reduced

During the Calvin cycle, carbon dioxide is _____, in order to drive the formation of sugars.

rubisco

The most abundant enzyme on Earth, which catalyzes the fixation of carbon dioxide in photosynthesis

false

True or false? The chemiosmotic hypothesis states that the synthesis of ATP generates a proton gradient that leads to electron flow through an electron transport chain.

true (The water molecules are split to replenish electrons in photosystem II, leaving behind protons, which are used to generate a proton gradient for the formation of ATP, and oxygen, which is released as a by-product.)

True or false? The light-dependent reactions of photosynthesis use water and produce oxygen.

false (The region of ATP synthase that catalyzes ATP production protrudes out of, but does not span, the chloroplast membrane; the region that spans the membrane is an ion channel through which protons can pass.)

True or false? The region of ATP synthase that catalyzes the production of ATP from ADP and inorganic phosphate spans the chloroplast membrane.

A (Light energy drives the formation of ATP and NADPH during the light-dependent reactions; these energy molecules are then used during the light-independent reactions to form sugars.)

Which of the following statements best describes the relationship between the light-dependent and light-independent reactions of photosynthesis? A) The light-dependent reactions produce ATP and NADPH, which are then used by the light-independent reactions. B) The light-dependent reactions produce carbon dioxide, which is then used by the light-independent reactions. C) The light-dependent reactions pass electrons through an electron transport chain to the light-independent reactions. D) The light-independent reactions release energy, and the light-dependent reactions require energy.

A

Which set of reactions uses H2O and produces O2? A) The light-dependent reactions B) The light-independent reactions

A

Which statement is most accurate concerning the solubility of starch or sucrose, as well as their use by plants? A) Sucrose is water soluble and used in respiration and sugar transport. B) Starch is not water soluble and is used in respiration and sugar transport. C) Starch is water soluble and used for sugar storage. D) Sucrose is not water soluble and is used for sugar storage.

A Engelmann showed that violet-to-blue and red photons are the most productive at stimulating photosynthesis. These are the same wavelengths absorbed by chlorophyll.

Why are violet-to-blue and red photons the most effective at driving photosynthesis? A) These are the wavelengths of light absorbed by chlorophyll molecules. B) These are the wavelengths of light absorbed by carotenoids. C) These are the wavelengths of light reflected by chlorophylls. D) These are the wavelengths of light transmitted by chlorophylls.

A Water "splitting" supplies a steady stream of electrons for PS II and is catalyzed by enzymes in the PS II complex.

Why can the rate of photosynthesis be estimated by measuring the rate of oxygen production in chloroplasts? A) Oxygen is produced by "splitting" water in the PS II complex. B) Oxygen is produced by splitting CO2 in the PS II complex. C) Oxygen is produced by "splitting" water in the PS I complex. D) The Calvin cycle produces oxygen.

A

Why does a leaf appear green when a person looks at it? A) The chlorophyll pigments absorb all wavelengths of light except in the green spectrum, which it reflects. B) Only the green wavelengths of light from the Sun reach the Earth. C) The chlorophyll pigments are colored green. D) The chlorophyll pigments reflect all wavelengths of light except in the green spectrum, which it absorbs.

C

Why is photosynthesis so important to life on Earth? A) Photosynthesis breaks down glucose, which provides ATP for all plants and animals. B) Photosynthesis releases carbon dioxide into the air, which is then used during cellular respiration, which in turn drives the release of oxygen, completing the respiration cycle. C) Photosynthesis captures light energy from the Sun and stores it in the bonds of glucose, which is then used during cellular respiration to drive the formation of ATP in all plants and animals. D) Photosynthesis is used to drive the formation of carbon dioxide, which releases the energy that allows the planet Earth to remain warm.

6 CO2 + 6 H2O → C6H12O6 + 6 O2

equation for photosynthesis