8.3 Photosynthesis [AHL]

Question 1

Explain the light-dependent reactions.

Answer 1

• uses light directly
• these reaction take place in the thylakoid space and across the thylakoid membranes
• the thyylakoid membranes are located on the interconnected membranes located on the inner membrane of the chloroplast

Question 2

Explain the light-independent reactions.

Answer 2

• does not use light directly
• reactions that can only carry on in the darkness but only for a few seconds b/cthey depend on substances produce by light-dependent reactions which rapidly run out

Question 3

How is NADP and ATP produced in the light-dependent reactions?

Answer 3

Light energy is converted into chemical enegry in the form of ATP and reduced NADP, which serve as energy sources

Question 4

Why does light-independednt reactions take place in the stroma?

Answer 4

• the stroma is loacated i the inner membrane of the cytoplasm
• the stroma is a thick protein-rich consisting of enezymes used in light-independent reactions aka Calvin cycle
• calvin cyle is an anabolic pathway that needs endergonic reactions in order to be coupled with hydrolysis of ATP and the oxidation of reduced NADP

Question 5

State all the light-dependent reactions.

Answer 5

• photolysis
• photoactivation
• electron transport
• chemiosmosis
• ATP synthesis
• reduction of NADP

Question 6

State all the light-independent reactions.

Answer 6

• carbon fixation
• carboxylation of RuBP
• production of triose phosphate
• ATP and NADPH as energy sources
• ATP used to regenerate RuBP
• ATP used to produce carbohydrates