Photosythesis

Question 1

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

a) electrons and H+
b) ADP, pi, and NADP+
c) CO2 and glucose
d) ATP and NADPH
e) H2O and O2

Answer 1

d) ATP and NADPH

Question 2

Reactions that require CO2 take place in

a) the Calvin cycle alone.
b) the light reactions alone.
c) both the light reactions and the Calvin cycle.
d) the chloroplast, but are not part of photosynthesis.
e) neither the light reactions nor the Calvin cycle.

Answer 2

a) The Calvin cycle alone

Question 3

Why are C4 plants able to photosynthesize with no apparent photorespiration?

Answer 3

They use PEP Carboxylase to initially fix CO2

Question 4

What wavelength of light is most effective in driving photosynthesis?

a) 730nm (red)
b) 475nm (blue)
c) 625nm (orange)
d) 575nm (green)
e) 420nm (violet)

Answer 4

e) 420nm

Question 5

When oxygen is released as a result of photosynthesis, it is a direct by-product of

Answer 5

splitting water molecules

Question 6

Photorespiration occurs when rubisco reacts RuBP with

Answer 6

O2

Question 7

Compared to C3 plants, C4 plants

a) grow better under cool, moist conditions
b) do not use rubisco
c) have higher rates of photorespiration
d) make a four-carbon compound, oxaloacetate, which is then delivered to the citric acid cycle in mitochondria
e) can continue to fix CO2 even at relatively low CO2 concentrations and high oxygen concentrations

Answer 7

e) can continue to fix CO2 even at relatively low CO2 concentrations and high oxygen concentrations

Question 8

A spaceship is designed to support animal life for a multiyear voyage to the outer planets of the solar system. Plants will be grown to provide oxygen and to recycle carbon dioxide.

If the power fails and the lights go dark, what will happen to CO2 levels?

a) CO2 will fall because plants will increase CO2 fixation
b) CO2 will rise as a result of animal respiration only
c) CO2 will rise as a result of animal and plant respiration
d) CO2 will remain balanced because plants will continue to fix CO2 in the dark
e) CO2 will fall because plants will cease to respire in the dark

Answer 8

C) CO2 will rise as a result of both animal and plant respiration

Question 9

Plants photosynthesize only in the light. Plants respire

a) only when excessive light energy induces photorespiration
b) in the light only
c) never-they get their ATP from photophosphorylation
d) in the dark only
e) both in light and dark

Answer 9

e) both in light and dark

Question 10

Where is the Calvin cycle located in a C4 plant?

a) bundle-sheath cells
b) mesophyll cells
c) stomata
d) stems
e) the chloroplasts in leaves

Answer 10

a) bundle-sheath cells

Question 11

CO2 + H2O → [CH2O] + O2 represents the simplified equation for

a) respiration
b) chemiosmosis
c) photosynthesis
d) photoposphorylation
e) chemisynthesis

Answer 11

c) photosynthesis

Question 12

In C3 photosynthesis, the reactions that require ATP take place in

a) the light reactions alone
b) the Calvin cycle alone
c) the chloroplast, but are not part of photosynthesis
d) neither the light reactions nor the Calvin cycle
e) both the light reactions and the Calvin cycle

Answer 12

b) the Calvin cycle alone

Question 13

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

a) thylakoid membranes
b) matrix of the mitochondria
c) stroma of the chloroplast
d) thylakoid space
e) cytosol around the chloroplast

Answer 13

c) stroma of the chloroplast

Question 14

If atmospheric CO2 concentrations increase twofold or more, how will plants be affected, disregarding any changes in climate?

a) C4 plants will have faster growth; C3 plants will be minimally affected.
b) C3 plants will have faster growth; C4 plants will be minimally affected.
c) Plant growth will not be affected because atmospheric CO2 concentrations are never limiting for plant growth.
d) C3 plants will have faster growth; C4 plants will have slower growth.
e) All plants will experience increased rates of photosynthesis.

Answer 14

b) C3 plants will have faster growth; C4 plants will be minimally affected

Question 15

CAM plants keep stomata closed in daytime, thus reducing loss of water. They can do this because they

a) use photosystem I and photosystem II at night
b) fix CO2 into organic acids during the night
c) fix CO2 into pyruvate in the mesophyll cells
d) use the enzyme phosphofructokinase, which outcompetes rubisco for CO2
e) fix CO2 into sugars in the bundle-sheath cells

Answer 15

b) fix CO2 into organic acids during the night

Question 16

What is the primary function of the Calvin cycle?

a) use NADPH to release carbon dioxide
b) synthesize simple sugars from carbon dioxide
c) split water and release oxygen
d) use ATP to release carbon dioxide
e) transport RuBP out of the chloroplast

Answer 16

b) synthesize simple sugars from carbon dioxide

Question 17

It is a particularly hot, dry summer. The town has banned excessive water use and so you cannot water your lawn. After a few weeks the grass has gone brown, except a few patches where the grass seems to be doing fine. You notice that this grass has a broader leaf and is not the same species as most of your lawn. You conclude that this grass is a

a) C4 plant
b) C3 plant
c) a mutant
d) C5 plant
e) CAM plant

Answer 17

a) C4 plant

Question 18

Photorespiration lowers the efficiency of photosynthesis by releasing (rather than fixing)

a) RuBP carboxylase molecules
b) ATP molecules
c) ribulose bisphosphate molecules
d) 3-phosphglycerate molecules
e) carbon dioxide molecules

Answer 18

e) carbon dioxide molecules

Question 19

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

a) thylakoid membranes
b) matrix of the mitochondria
c) stroma of the chloroplast
d) thylakoid space
e) cytosol around the chloroplast

Answer 19

c) stroma of the chloroplast

Question 20

Why are C4 plants able to photosynthesize with no apparent photorespiration?

a)They use PEP carboxylase to initially fix CO2
b) They are adapted to cold, wet climates
c) They exclude oxygen from their tissues
d) They conserve water more efficiently
e) They do not participate in the Calvin cycle

Answer 20

a) They use PEP carboxylase to initially fix CO2

Question 21

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

a) 730nm
b) 475nm
c) 625nm
d) 575nm
e) 420nm

Answer 21

e) 420nm

Question 22

CO2 + H2O → [CH2O] + O2 represents the simplified equation for…

a) respiration
b) chemiosmosis
c) photosynthesis
d) photophosphorylation
e) chemisynthesis

Answer 22

c) photosynthesis

Question 23

If the process of photosynthesis had never evolved on Earth, this planet would..

a) have no land and be primarily ocean
b) have no water and be dry land
c) be very similar to the way it is today
d) have no oxygen and thus no life
e) only contain anaerobic organisms

Answer 23

e) only contain anaerobic organisms

Question 24

The NADPH required for the Calvin cycle comes from…

a) oxidative phosphorylation
b) reactions initiated in photosystem II
c) reactions initiated in photosystem I
d) the citric acid cycle
e) glycolysis

Answer 24

c) reactions initiated in photosystem I

Question 25

Photorespiration lowers the efficiency of photosynthesis by releasing (rather than fixing)…

a) RuBP carboxylase molecules
b) ATP molecules
c) ribulose bisphosphate molecules
d) 3-phosphoglycerate molecules
e) carbon dioxide molecules

Answer 25

e) carbon dioxide molecules

Question 26

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

a) electrons and H+
b) ADP, Pi, NADP +
c) CO2 and glucose
d) ATP and NADPH
e) H2O and O2

Answer 26

ATP and NADPH

Question 27

Which molecule(s) of the Calvin cycle is (are) also found in glycolysis?

a) B, C, and E only
b) 3-phosphoglycerate only
c) B, C, E, and 3-phosphoglycerate
d) E only
e) B, C, D, and 3-phosphoglycerate only

Answer 27

e) B, C, D, and 3-phosphoglycerate only

Question 28

In a plant leaf, the reactions that produce NADH occur in

a) both the light reactions and the Calvin cycle
b) neither the light reactions nor the Calvin cycle
c) the Calvin cycle alone
d) the chloroplast, but are not part of photosynthesis
e) the light reactions alone

Answer 28

b) neither the light reactions nor the Calvin cycle