C1.3 Photosynthesis

Limiting Factors of Photosynthesis

Temperature, light intensity and CO2 concentration

What are Thylakoids?

Membranous sacs that do light-dependent reactions

What are photosystems

Pigment/protein complexes in thylakoid membranes that absorb light

Best wavelength for absorption of photosystem II

P680

Best wavelength for absorption of photosystem I

P700

Reaction at Photosystem II

Photolysis of water into oxygen, hydrogen ions and electrons

How is the proton gradient in the thylakoid created?

The photolysis of water at photosytem II

What is chemiosmosis?

The movement of ions across a membrane according to their concentration gradient

Function of Cytochrome

Pumps protons into inner thylakoid

How is ATP produced?

Energy released in the movement of electrons is used to pump hydrogen ions across the membrane from stroma to inner thylakoid, and movement of protons through ATP synthase photo-phosphorylates ATPs

What is the role of NADP?

NADP is an electron carrier that is either oxidized or reduced in photosynthesis.

Role of photosystem I

Reduces NADP (using NADP reductase)

Difference between cyclic and non-cyclic phosphorylation

In cyclic phosphorylation, NADP is not reduced and the electron is recycled to produce ATP

Where does the Calvin Cycle occur?

In the stroma

Role of Rubisco

Fixes carbon from the atmosphere

What reaction does Rubisco catalyze?

3 RuBP (5C) + CO2 → 6GP (3C)

Full name of GP

Glycerate-3-phosphate

Synthesis of Triose Phosphate reaction

6GP (3C) → 6TP (3C)

Function of TP

5 are used to regenerate RuBP, 1 is converted to glucose/other biomolecules

How many turns of the Calvin cycle per one glucose molecule?

6 turns

Relationship between light-dependent and light-independent reactions

Interdependent on each other