Gen. Bio. Quiz 2: Photorespiration, C4 & CAM

Question 1

The first organic product of carbon fixation is a _____________.

Answer 1

3-Carbon compound
(3-Phosphoglyceric Acid)

Question 2

During hot and dry days:
a. Stomata is _________
b. ________ of CO2 level in the leaves
c. O2 level ___________

Answer 2

a. close
b. decline
c. builds up

Question 3

RuBisCO is not loyal to CO2.
When plants close their stomata, rubisco (the carbon-fixing enzyme of Calvin cycle) grabs the ____ rather than CO2.

Answer 3

O2

Question 4

Evolutionary Baggage.
a. Low Temperature: ______ CO2:O2 ratio
b. High Temperature: _______ CO2:O2 ratio

Answer 4

a. High (RuBisCO grabs CO2 to bind with RuBP)
b. Low (RuBisCO grabs O2 to bind with RuBP)

Question 5

Once O2 binds with RuBP, it forms:

Answer 5

1 molecule of 3-PGA and 1 molecule of 2-phosphoglycolate

Question 6

The 2-phosphoglycolate is
a. ________ to plants
b. inhibits distinct reactions in the Calvin cycle.

Answer 6

a. toxic

Question 7

A wasteful metabolic pathway that decreases the photosynthetic output.

Answer 7

Photorespiration

Question 8

Photorespiration.
a. Uses ______ rather than generating it.
b. No _______ is produced.
c. ______ is lost rather than having it fixed (50%)

Answer 8

a. ATP
b. sugar
c. CO2

Question 9

Photorespiration.
This prevents light-induced damage to the molecules involved in photosynthesis.

(It deals with the problems of too much sunlight during photosynthesis so that photorespiration won’t waste so much energy)

Answer 9

Photoprotective Effects

Question 10

Photorespiration.
d. This help maintain _____________ in cells.
e. support plant immune defenses

Answer 10

d. redox balance

(acts like a safety valve that absorbs excess energy to prevent overload)

Question 11

Plants that are common in habitats that are hot, but are less abundant in areas that are cooler.

Answer 11

C4 Plants

Question 12

C4 PLANTS is named so because the first stable molecule from the fixation of CO2 is a __________

Answer 12

4-carbon organic acid

Question 13

C4 Photosynthesis.
a. Begins in ___________ (light-dependent reaction) and is completed in ___________ cells (Calvin cycle)

Answer 13

a. mesophyll cells; bundle-sheath cells

Question 14

C4 Photosynthesis.
A special structure in the leaves of C4 plants where the tissue equivalent to spongy mesophyll cells is clustered in a ring around the leaf veins outside the bundle sheath cells.

Answer 14

Kranz anatomy

Question 15

C4 Photosynthesis.
C4 plants expend _______ (#) ATP to synthesize 1 molecule of glucose.

Answer 15

12 more ATP

Question 16

C4 Photosynthesis.
The goal is to increase the concentration of _______.

Answer 16

CO2

Question 17

What does CAM mean?

Answer 17

Crassulacean Acid Metabolism

Question 18

This occurs in the mesophyll cells: ________________
* Day: stomata is ______ (conserves water and collects sunlight)
* Night: stomata is _____ (takes/fixes CO2)

Answer 18

CAM Photosynthesis
* Day: stomata is close
* Night: stomata is open

Question 19

NADPH and ATP.
a. C4 Plants: ____ (#) NADPH and ____ (#) ATP to produce glucose.
b. CAM Plants: ______ (#) NADPH and _______ (#) ATP.

Answer 19

a. 12 NADPH and 18 ATP
b. 12 NADPH and 39 ATP