Chapter 11: Photosynthesis

Question 1

In a rosebush, chlorophyll is located in __________.

Chlorophyll molecules are in which part of the chloroplast?

Answer 1

thylakoids, which are in chloroplasts in the mesophyll cells of a leaf
thylakoid membranes

Question 2

In photosynthesis, what is the fate of the oxygen atoms present in CO2? They end up __________.
How about in H2O?

Answer 2

The oxygen atoms present in carbon dioxide appear in sugar and water. The oxygen produced by photosynthesis comes from the splitting of water.

Question 3

The light reactions of photosynthesis generate * (specifically: *) when water is split

Answer 3

molecular oxygen

linear electron flow during the light reactions

Question 4

The reactions of the Calvin cycle are NOT directly dependent on light, but they usually do NOT occur at night. Why?

Answer 4

The Calvin cycle requires products only produced when the photosystems are illuminated.
The ATP and NADPH produced during the light reactions are necessary for the Calvin cycle.

Question 5

The light reactions occur in the * while the Calvin cycle occurs in the __________

Answer 5

The thylakoids of the chloroplast are the sites of the light reactions, whereas the Calvin cycle occurs in the stroma.

Question 6

The most important role of pigments in photosynthesis is to _________

Answer 6

capture light energy

Question 7

What is the range of wavelengths of light that are absorbed by the pigments in the thylakoid membranes?

Answer 7

blue-violet and red-orange

Question 8

Based on the work of Engelmann, a plot of photosynthetic activity versus wavelength of light is referred to as __________.

Answer 8

an action spectrum, An action spectrum plots the effectiveness of different wavelengths of light in driving photosynthesis.

Question 9

What consists of photosystem?

Answer 9

the reaction center, light-harvesting complexes, and primary electron acceptors

Question 10

Which of the following is cycled in the cyclic variation of the light reactions?

Answer 10

electrons: During the light reactions of photosynthesis, there are two possible routes for electron flow: cyclic and linear.

Question 11

Both mitochondria and chloroplasts use __________ to generate ATP

Answer 11

chemiosmosis: An electron transport chain in the membrane pumps protons across the membrane as electrons are passed through a series of carriers that are progressively more electronegative. Built into the same membrane is an ATP synthase that couples the diffusion of hydrogen ions down their gradient to the phosphorylation of ADP.

Question 12

During photosynthesis in a eukaryotic cell, an electrochemical gradient is formed across the __________.

Answer 12

thylakoid membrane

Question 13

The energy used to produce ATP in the light reactions of photosynthesis comes from __________.

Answer 13

movement of H+ through a membrane: Termed “chemiosmosis,” the diffusion of hydrogen ions through ATP synthase provides the energy to produce ATP.

Question 14

What is the role of NADP+ in photosynthesis?

Answer 14

It is reduced and then carries electrons to the Calvin cycle.

Question 15

Which of the following occurs during the Calvin cycle? (

about atp and nadph

Answer 15

ATP is hydrolyzed and NADPH is oxidized. The hydrolysis of ATP releases energy to drive the endergonic reactions of the Calvin cycle, and the oxidation of NADPH provides high-energy electrons for the reduction of the carbon from carbon dioxide.

Question 16

Rubisco is __________.

Answer 16

the enzyme in plants that captures CO2 to begin the Calvin cycle. The enzyme that catalyzes the first step of the Calvin cycle (incorporation of a molecule of carbon dioxide by attaching it to a five-carbon sugar, named ribulose biphosphate, or RuBP) is RuBP carboxylase, or rubisco.

Question 17

In the Calvin cycle, CO2 is combined with __________.

Answer 17

a five-carbon compound to form an unstable six-carbon compound, which decomposes into two three-carbon compounds: Rubisco catalyzes the first step of the Calvin cycle—the incorporation of a molecule of carbon dioxide with a five-carbon sugar. The six-carbon product is so unstable that it decomposes immediately into two three-carbon phosphoglycerates.

Question 18

Glyceraldehyde-3-phosphate (G3P) is produced in the stroma of chloroplasts. Which of the following statements is most accurate regarding this compound?
For every three molecules of CO2, six molecules of G3P are formed but five molecules must be recycled to regenerate three molecules of RuBP
It is a three-carbon sugar.
It is produced from glucose during glycolysis.
For every three molecules of CO2 reduced in the Calvin cycle, six molecules of G3P are formed but only one of these molecules exits the cycle to be used by the plant cell.
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Answer 18

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