Compared with the lines for chlorophyll a in the figure, where would you expect to find the lines to differ for chlorophyll b?

The absorption spectrum line would be lowest for chlorophyll b somewhat to the right of that for chlorophyll a (500—600).

The rate of photosynthesis line for chlorophyll b would be lowest from 600—700 nm.

The lines for the two types of chlorophyll would be almost completely opposite.

The lines for the two types of chlorophyll would be almost completely identical.

The peaks of the line for absorbance of b would be shifted to the left, and for rate of photosynthesis would be shifted to the right.

In the thylakoid membranes, what is the main role of the antenna pigment molecules?

harvest photons and transfer light energy to the reaction-center chlorophyll

split water and release oxygen to the reaction-center chlorophyll

transfer electrons to ferredoxin and then NADPH

concentrate photons within the stroma

The reaction-center chlorophyll of photosystem I is known as P700 because

this pigment is best at absorbing light with a wavelength of 700 nm.

there are 700 chlorophyll molecules in the center.

there are 700 photosystem I components to each chloroplast.

it absorbs 700 photons per microsecond.

the plastoquinone reflects light with a wavelength of 700 nm.

Which of the events listed below occur in the light reactions of photosynthesis?

light is absorbed and funneled to reaction-center chlorophyll a.

carbon dioxide is incorporated into PGA.

ATP is phosphorylated to yield ADP.

Which statement describes the functioning of photosystem II?

The electron vacancies in P680 are filled by electrons derived from water.

Light energy excites electrons in the electron transport chain in a photosynthetic unit.

The excitation is passed along to a molecule of P700 chlorophyll in the photosynthetic unit.

The P680 chlorophyll donates a pair of protons to NADPH, which is thus converted to NADP+.

The splitting of water yields molecular carbon dioxide as a by-product.

Which of the following are directly associated with photosystem I?

receiving electrons from plastocyanin

harvesting of light energy by ATP

P680 reaction-center chlorophyll

extraction of hydrogen electrons from the splitting of water

passing electrons to plastoquinone

Some photosynthetic organisms contain chloroplasts that lack photosystem II, yet are able to survive. The best way to detect the lack of photosystem II in these organisms would be

to test for liberation of O2 in the light.

to determine if they have thylakoids in the chloroplasts.

to test for CO2 fixation in the dark.

to do experiments to generate an action spectrum.

to test for production of either sucrose or starch.

Assume a thylakoid is somehow punctured so that the interior of the thylakoid is no longer separated from the stroma. This damage will have the most direct effect on which of the following processes?

the absorption of light energy by chlorophyll

the flow of electrons from photosystem II to photosystem I

What does the chemiosmotic process in chloroplasts involve?

establishment of a proton gradient

diffusion of electrons through the thylakoid membrane

reduction of water to produce ATP energy

movement of water by osmosis into the thylakoid space from the stroma

formation of glucose, using carbon dioxide, NADPH, and ATP

Suppose the interior of the thylakoids of isolated chloroplasts were made acidic and then transferred in the dark to a pH-8 solution. What would be likely to happen?

A) The isolated chloroplasts will make ATP.

B) The Calvin cycle will be activated.

C) Cyclic photophosphorylation will occur.

In a plant cell, where are the ATP synthase complexes located?

C) inner mitochondrial membrane

In mitochondria, chemiosmosis translocates protons from the matrix into the intermembrane space, whereas in chloroplasts, chemiosmosis translocates protons from

the intermembrane space to the matrix.

the stroma to the photosystem II.

the stroma to the thylakoid space.

ATP synthase to NADP+ reductase.

Which of the following statements best describes the relationship between photosynthesis and respiration?

Photosynthesis stores energy in complex organic molecules, while respiration releases it.

Respiration is the reversal of the biochemical pathways of photosynthesis.

Photosynthesis occurs only in plants and respiration occurs only in animals.

ATP molecules are produced in photosynthesis and used up in respiration.

Respiration is anabolic and photosynthesis is catabolic.

Where are the molecules of the electron transport chain found in plant cells?

thylakoid membranes of chloroplasts

Synthesis of ATP by the chemiosmotic mechanism occurs during

both photosynthesis and respiration.

neither photosynthesis nor respiration.

Reduction of oxygen which forms water occurs during

both photosynthesis and respiration.

neither photosynthesis nor respiration.

Reduction of NADP+ occurs during

both photosynthesis and respiration.

neither photosynthesis nor respiration.

The splitting of carbon dioxide to form oxygen gas and carbon compounds occurs during

neither photosynthesis nor respiration.

both photosynthesis and respiration.

Generation of proton gradients across membranes occurs during

both photosynthesis and respiration.

neither photosynthesis nor respiration.

What is the relationship between wavelength of light and the quantity of energy per photon?

They have a direct, linear relationship.

They are logarithmically related.

They are only related in certain parts of the spectrum.

In a protein complex for the light reaction (a reaction center), energy is transferred from pigment molecule to pigment molecule, to a special chlorophyll a molecule, and eventually to the primary electron acceptor. Why does this occur?

The molecular environment lets it boost an electron to a higher energy level and also to transfer the electron to another molecule.

The action spectrum of that molecule is such that it is different from other molecules of chlorophyll.

The potential energy of the electron has to go back to the ground state.

Each pigment molecule has to be able to act independently to excite electrons.

These chlorophyll a molecules are associated with higher concentrations of ATP.

P680+ is said to be the strongest biological oxidizing agent. Why?

This molecule results from the transfer of an electron to the primary electron acceptor of photosystem II and strongly attracts another electron.

It is the receptor for the most excited electron in either photosystem.

It is the molecule that transfers electrons to plastoquinone (Pq) of the electron transfer system.

NADP reductase will then catalyze the shift of the electron from Fd to NADP+ to reduce it to NADPH.

This molecule is found far more frequently among bacteria as well as in plants and plantlike Protists.

Some photosynthetic bacteria (e.g., purple sulfur bacteria) have photosystem I but not II, while others (e.g. cyanobacteria) have both PSI and PSII. Which of the following might this observation imply?

Photosystem I must be more ancestral.

Photosystem II must have been selected against in some species.

Photosystem II may have evolved to be more photoprotective.

Cyclic flow must be more primitive than linear flow of electrons.

Cyclic flow must be the most necessary of the two processes.

Cyclic electron flow may be photoprotective (protective to light-induced damage). Which of the following experiments could provide information on this phenomenon?

using mutated organisms that can grow but that cannot carry out cyclic flow of electrons and compare their abilities to photosynthesize in different light intensities

using plants that can carry out both linear and cyclic electron flow, or only one or another of thee processes, and measuring their light absorbance

using bacteria that have only cyclic flow and look for their frequency of mutation damage

using bacteria with only cyclic flow and measuring the number and types of photosynthetic pigments they have in their membranes

using plants with only photosystem I operative and measure how much damage occurs at different wavelengths.

Carotenoids are often found in foods that are considered to have antioxidant properties in human nutrition. What related function do they have in plants?

They dissipate excessive light energy.

They serve as accessory pigments.

They cover the sensitive chromosomes of the plant.

They take up toxins from the water.

In thylakoids, protons travel through ATP synthase from the stroma to the thylakoid space. Therefore the catalyticȱȈknobsȈȱof ATP synthase would be located

on the stroma side of the membrane.

on the side facing the thylakoid space.

on the ATP molecules themselves.

on the pigment molecules of PSI and PSII.

built into the center of the thylkoid stack (granum).

Which of the following statements best represents the relationships between the light reactions and the Calvin cycle?

The light reactions provide ATP and NADPH to the Calvin cycle, and the cycle returns ADP, Pi, and NADP+ to the light reactions.

The light reactions provide ATP and NADPH to the carbon fixation step of the Calvin cycle, and the cycle provides water and electrons to the light reactions.

The light reactions supply the Calvin cycle with CO2 to produce sugars, and the Calvin cycle supplies the light reactions with sugars to produce ATP.

The light reactions provide the Calvin cycle with oxygen for electron flow, and the Calvin cycle provides the light reactions with water to split.

There is no relationship between the light reactions and the Calvin cycle.

What is the primary function of the Calvin cycle?

synthesize simple sugars from carbon dioxide

use ATP to release carbon dioxide

use NADPH to release carbon dioxide

transport RuBP out of the chloroplast