Bio ch.8
Generation of proton gradients across membranes occurs during
both photosynthesis and respiration
n photosynthetic cells, synthesis of ATP by the chemiosmotic mechanism occurs during
both photosynthesis and respiration
The reactions that produce molecular oxygen (O₂) take place in
the light reactions alone
The light reactions of photosynthesis supply the Calvin cycle with
ATP and NADPH
Which of the following are products of the light reactions of photosynthesis that are utilized in the Calvin cycle?
ATP and NADPH
Which of the events listed below occurs in the light reactions of photosynthesis?
Light is absorbed and funneled to reaction-center chlorophyll a
Photorespiration occurs when rubisco reacts RuBP with
O₂
Which of the following statements best describes the relationship between photosynthesis and respiration?
Photosynthesis stores energy in complex organic molecules, whereas respiration releases it.
Which statement describes the functioning of photosystem II?
The electron vacancies in P680⁺ are filled by electrons derived from water.
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
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.
P680⁺ is said to be the strongest biological oxidizing agent. Why?
This molecule has a stronger attraction for electrons than oxygen, to obtain electrons from water.
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
Plants photosynthesize only in the light. Plants respire
both in light and dark
What does the chemiosmotic process in chloroplasts involve?
establishment of a proton gradient across the thylakoid membrane
The splitting of carbon dioxide to form oxygen gas and carbon compounds occurs during
neither photosynthesis nor respiration
In thylakoids, protons travel through ATP synthase from the thylakoid space to the stroma. Therefore, the catalytic "knobs" of ATP synthase would be located
on the stroll side of the membrane
Reduction of NADP+ occurs during
photosynthesis
Reduction of NADP⁺ occurs during
photosynthesis
The NADPH required for the Calvin cycle comes from
reactions initiated in photosystem I.
Which of the following are directly associated with photosystem I?
receiving electrons from the thylakoid membrane electron transport chain
Which of the following does not occur during the Calvin cycle?
release of oxygen
Reduction of oxygen to form water occurs during
respiration only
When oxygen is released as a result of photosynthesis, it is a direct by-product of
splitting water molecules
Where do the enzymatic reactions of the Calvin cycle take place?
stroma and chloroplast
Where does the Calvin cycle take place?
stroma of the chloroplast
What is the primary function of the Calvin cycle?
synthesize simple sugars from carbon dioxide
Reactions that require CO₂ take place in
the Calvin cycle alone
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
n the process of carbon fixation, RuBP attaches a CO₂ to produce a six-carbon molecule, which is then split to produce two molecules of 3-phosphoglycerate. After phosphorylation and reduction produces glyceraldehyde 3-phosphate (G3P), what more needs to happen to complete the Calvin cycle?
the regeneration of RuBP
In mitochondria, chemiosmosis translocates protons from the matrix into the intermembrane space, whereas in chloroplasts, chemiosmosis translocates protons from
the storm to the thylakoid space
What is the relationship between wavelength of light and the quantity of energy per photon?
they are inversely related
In a plant cell, where are the ATP synthase complexes located?
thylakoid membrane and inner mitochondrial membrane
Where are the molecules of the electron transport chain found in plant cells?
thylakoid membranes of chloroplasts