Photosynthesis

Question 1

In which layer in the leaf does photosynthesis occur?

Answer 1

Palisade Layer

Question 2

Where specifically does light dependent reactions occur in a chloroplast?

Answer 2

Thylakoid membrane

Question 3

What is a granum?

Answer 3

A stack of thylakoids

Question 4

What is the job of a lamella?

Answer 4

Joins the thylakoids together horizontally

Question 5

Chlorophyll A, Xanthophyll, and Carotenoids are all classed as what?

Answer 5

Photosynthetic Pigments

Question 6

What does an action spectrum show?

Answer 6

The rate of photosynthesis

Question 7

What happens to the electrons in the primary pigment reaction centres?

Answer 7

They become excited and leave

Question 8

What is the job of accessory pigments?

Answer 8

To pass light energy to the primary pigment by donating its electrons to neutralise the positive charge of the primary pigment

Question 9

Describe the 4 main stages of cyclic phosphorylation

Answer 9

1. Light energy is absorbed by PSII
2. Electrons gain this energy and become excited, and so leave the chlorophyll
3. The electrons are accepted by electron accepters to PSI
4. Energy is released during stage 3, which is used to create ATP

Question 10

What process occurs first, cyclic or non-cyclic phosphorylation?

Answer 10

Non-Cyclic

Question 11

Describe the 4 stages that occur in non-cyclic phosphorylation

Answer 11

1. Light energy is abosrbed from PSI
2. Electrons gain this energy and become excited, and so leave the chloropyll molecule
3. These electrons are accepted by electron accepters which pass these onto the enzyme NADP reductase to reduce 2 moleules of NADP

Question 12

What part does the photolysis of water have to play in the reduction of NADP?

Answer 12

Light energy splits water into H+, e-, and oxygen. The electrons are donated to PSII to neutralise the charge, and the H+ are used to reduce NADP

Question 13

Where does the NADP used in the light dependant reactions come from?

Answer 13

Light independant reactions

Question 14

What is another name for light independant stage of photosynthesis?

Answer 14

The calvin cycle

Question 15

Where does the light independant stage of photosynthesis occur?

Answer 15

The stroma of the chloroplast

Question 16

Describe the key 3 stages in the light independent stage of photosynthesis

Answer 16

1. CO2 and RuBP are combined in the enzyme Rubisco to from an unstable 6C compound, which breaks down to 2 moleucles of GP (3 carbons)
2. GP is converted to TP using the energy produces form the breakdown of ATP, and the H+ ions from the NADPred, all of which came from the light dependant stage
3. ATP (also from the light dependant stage) is broken down to produce ADP and P(i), which is used to resynthesise RuBP

Question 17

What are the factors that affect the rate of photosynthesis?

Answer 17

Light intensity
CO2 concentration
Tempreture

Question 18

What effect does dim light have on the concentrations of NADPred, ATP, and GP?

Answer 18

Increased : GP

Decreased : NADPred and ATP

Question 19

What happens to CO2 in the light independent reactions?

Answer 19

Joins rubsicso

Question 20

How does pyruvate get into the mitochondria?

Answer 20

Active transport