Lecture 3 - Photosynthesis pt. 2

Question 1

3 Major reactions in the Calvin cycle

Fixation or ________ reaction

Answer 1

carboxylation

Question 2

3 Major reactions in the Calvin cycle

__________ or conversion of sugars to different forms

Answer 2

reduction

Question 3

3 major reactions in the Calvin cycle

__________ or use of energy to regenerate RUBP

Answer 3

regeneration

Question 4

Photorespiration

uses ______ ATP and _______ NADPH for every oxygenation of RuBP

Answer 4

5, 3

Question 5

Photorespiration results in (lower/higher) rate of dry matter production because of (lower/higher) photosynthetic efficiency

Answer 5

lower, lower

Question 6

Category of plants based on their Carbon fixation pathway

the first stable intermediate has three carbons enter the Calvin cycle directly

Answer 6

C3 plants

Question 7

example of C3 plants

Answer 7

rice, wheat, soybeans

Question 8

Category of plants based on their Carbon fixation pathway

first incorporate carbon dioxide into four-carbon compounds before Calvin cycle

Answer 8

C4 plants

Question 9

example of C4 plants

Answer 9

corn, sugarcane

Question 10

C4 plants’ Carbon fixation pathway is adaptive, because it enhances carbon fixation under conditions that favor photorespiration, such as ________, ________ environments

Answer 10

hot, arid

Question 11

C4 pathway is also called _______-_______ pathway because photosynthetic reactions occur in separate cells (________ and ________ ________ cells)

Answer 11

hatch-slack, mesophyll, bundle sheath

Question 12

Mesophyll cells in C4 plants have an additional enzyme, PEP carboxylase or ________

Answer 12

phosphoenol pyruvate carboxylase

Question 13

C4 photosynthesis

1) CO2 enters _________ cells
2) PEP is carboxylated to form OAA or ___________ acid
3) OAA is converted to _________
4) Malate is transported to __________ __________ cells through malate pump
5) __________ is released via decarboxylation and enters Calvin cycle
6) Rubisco in the Calvin cycle acts as a ___________ always

Answer 13

mesophyll
ocaloacetic
malate
bundle sheath
CO2
carboxylase

Question 14

True or False. All plants have both the light-dependent and light-independent reactions

Answer 14

True

Question 15

CAM pathway meaning

Answer 15

Crassulacean acid metabolism

Question 16

Examples of CAM plants

Answer 16

cacti, succulents, pineapple

Question 17

CAM exhibited by plants in what type of environment?

Answer 17

hot, dry, arid

Question 18

in CAM plants, light and dark reactions are separated in time (__________ separation)

• stomata open at _______ to allow entry of CO2
• C4 pathway occurs at ________
• Calvin cycle occurs in ________

Answer 18

temporal

night
night
daylight

Question 19

C3 vs C4 vs CAM

light intensity?

Answer 19

C3: normal light
C4: high light intensity

Question 20

C3 vs C4 vs CAM

environmental conditions?

Answer 20

C3: cool and moist
C4: high temperatures
CAM: arid conditions