AP BIO PHOTOSYNTHESIS

Which of the following are products of the light reactions of photosynthesis that are utilized in the Calvin cycle?

ATP and NADPH

Where does the calvin cycle take place?

stroma of the chloroplast

When oxygen is released as a result of photosynthesis, it is a by-product of which of the following?

splitting the water molecules

A plant has a unique photosynthetic pigment. The leaves of this plant appear to be reddish yellow. What wavelengths of visible light are being absorbed by this pigment?

blue and violet

What did Engelmann conclude about the congregation of bacteria in the red and blue areas?

Bacteria congregated in these areas because these areas had the most oxygen being released.

An outcome of this experiment was to help determine

the relationship between wavelengths of light and the oxygen released during photosynthesis.

Figure 10.1 shows the absorption spectrum for chlorophyll a and the action spectrum for photosynthesis. Why are they different?

Other pigments absorb light in addition to chlorophyll a.

what wavelength of light in the figure is most effective in driving photosynthesis?

420mm

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

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.

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

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

Which statement describes the functioning of photosystem II?

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

Which of the following are directly associated with photosystem I?

receiving electrons from plastocyanin

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.

What are the products of linear photophosphorylation?

ATP and NADPH

As a research scientist, you measure the amount of ATP and NADPH consumed by the Calvin cycle in 1 hour. You find 30,000 molecules of ATP consumed, but only 20,000 molecules of NADPH. Where did the extra ATP molecules come from?

cyclic electron flow

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?

The isolated chloroplasts will make ATP.

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

A and C

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

the stroma to the thylakoid space.

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

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

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

Reduction of oxygen which forms water occurs during

respiration

Reduction of NADP+ occurs during

photosynthesis

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

neither photosynthesis nor respiration

Generation of proton gradients across membranes occurs during

both photosynthesis and respiration

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.

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.

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.

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.

Where do the enzymatic reactions of the Calvin cycle take place?

stroma of the chloroplast

What is the primary function of the Calvin cycle?

synthesize simple sugars from carbon dioxide

produces molecule oxygen

light reactions alone

Requires ATP

the calvin cycle alone

Produces NADH

neither

Produces NADPH

light reactions alone

Produces three-carbon sugars

The calvin cycle alone

requires CO2

the calvin cycle alone

requires glucose

neither the light reactions or the calvin cycle

The sugar that results from three ʺturnsʺ of the Calvin cycle is glyceraldehyde-3-phosphate (G3P). Which of the following is a consequence of this?

The formation of starch in plants involves assembling many G3P molecules, with or without further rearrangements.

In the process of carbon fixation, RuBP attaches a CO2 to produce a 6 carbon molecule, which is then split in two. After phosphorylation and reduction, what more needs to happen in the Calvin cycle?

regeneration of rubisco

If ATP used by this plant is labeled with radioactive phosphorus, in which molecules will the radioactivity be measurable after one ʺturnʺ of the cycle?

in B, C, D, and E

The pH of the inner thylakoid space has been measured, as have the pH of the stroma and of the cytosol of a particular plant cell. Which, if any, relationship would you expect to find?

The pH within the thylakoid is less than that of the stroma.

Which of the following statements is true concerning Figure 10.3?

It represents cell processes involved in C4 photosynthesis.

Referring to Figure 10.3, oxygen would inhibit the CO2 fixation reactions in

Cell II only

In which cell would you expect photorespiration?

Cell II

Why are C4 plants able to photosynthesize with no apparent photorespiration

They use PEP carboxylase to initially fix CO2.

Which of the following sequences correctly represents the flow of electrons during photosynthesis?

H2O → NADPH → Calvin cycle

How is photosynthesis similar in C4 and CAM plants?

In both cases, rubisco is not used to fix carbon initially.

Which process is most directly driven by light energy?

removal of electrons from chlorophyll molecules

Which of the following does not occur during the Calvin cycle?

release of oxygen