Photosynthesis II + Alternative Photosystem

Question 1

____ (cycle) results in Pumping of Protons

Answer 1

Q-cycle

Question 2

PSI reduces NADP+ to NADPH in the stroma by the action of

Answer 2

ferredoxin (Fd) & flavoprotein ferredoxin- NADP reductase (FNR)

Question 3

ATP synthesis during light reaction of photosynthesis is known as

Answer 3

photophosphorylation

Question 4

Refers to the process of moving ions to the other side of the membrane resulting in the generation of an electrochemical gradient that can be used to drive ATP synthesis

Answer 4

Chemiosmosis

Question 5

Chemiosmosis is driven by

Answer 5

electrochemical proton gradient

Question 6

Created by electron transport chain either during oxidation of NDH or photosynthesis in chloroplasts

Answer 6

Proton gradient

Question 7

A complex set of molecular processes, defined as the inhibition of photosynthesis by excess light.

Answer 7

Photoinhibition

Question 8

The 2nd Redox reaction of Photosynthesis:
- occurs in?
- the 2nd set of redox phase includes ____which uses chemical energy, NADH and ATP generated during 1st phase

Answer 8

1. Stroma
2. CO2 assimilation

Question 9

1. Calvin-Benson Cycle is also known as
   - elucidated by?

Answer 9

Reductive-pentose phosphate pathway
by Melvin Calvin, James Bassham, Andrew Benson (1961)

Question 10

Calvin Cycle stages

Answer 10

1- Carbon Fixation
2- Reduction of 3-PGA to G3P
3. Regeneration of RuBP

Question 11

The first actual sugar produced in Calvin Cycle

Answer 11

G3P

Question 12

Five light-regulated enzymes operate in the calvin cyle

Answer 12

1. Rubisco
2. NADP: glyceraldehyde-3-phosphate dehydrogenase
3. Fructose-1,6-bisphosphatase
4. Sedoheptulose-1,7-bisphosphatase
5. Ribulose-5-phosphate kinase

Question 13

Rubisco activity increases in the

Answer 13

Light

Question 14

Light- dependent ion movement regulate ____

Answer 14

Calvin cycle enzymes

Question 15

(Alternative Photosystem part)
Non-O2-evolving (anoxygenic) organisms, such as the purple photosynthetic bacteria of the genera ____ and ____, contain only a single photosystem

Answer 15

Rhodobacter and Rhodopseudomonas

Question 16

a photosynthetic pathway that allows plants to fix carbon dioxide more efficiently in hot, dry conditions.

Answer 16

C4 Metabolism

Question 17

C4 species:

Answer 17

monocots of hot climates such as corn, sugarcane, sorghu, and some grasses

Question 18

(CO2- Concentrating Mechanisms)
Kranz anatomy is a specialized leaf structure that is found in C4 plants. It is characterized by two distinct cell types:

Answer 18

mesophyll cells and bundle sheath cells.

Question 19

(CO2- Concentrating Mechanisms)
The C4 cyle concentrates CO2 in bundle sheath cells.
The basic C4 cycle consists of four stages:

Answer 19

1. Fixation of CO2
   - carboxylation of phosphoenolpyruvate in the mesophyll cells to form a C4 acid
2. Transport of the C4 acids
   - to the bundle sheath cells
3. Decarboxylation of the C4 acids
   - and generation of CO2, which is reduced to carbohydrates via Calvin cycle
4. Transport of the C3 acid
   - formed by the decarboxylation step back to the mesophyll cell and regeneration of the CO2 acceptor phosphoenolpyruvate

Question 20

C3 plants regulate ____ of their leaves during the day, and _____ during the night

Answer 20

stomatal aperture (day)
stomata close (night)

Question 21

C4 and CAM plants utilize _____ to fix CO2

Answer 21

PEP carboxylase

Question 22

C3 and C4 plants photosynthesize all day,
whereas CAM plants may stop before noon. (true or false)

Answer 22

True

Question 23

What mechanism allows photosynthetic organisms to fix CO2 more efficiently in low CO2 environments

Answer 23

CO2 Concentrating Mechanisms (CCM’s)