Photosynthesis

Question 1

How would you draw and label a chloroplast

Answer 1

Should include double membrane, stroma, thylakoids, grana and intergranal lamellae. May include circular DNA, 70s ribosomes and starch granules

Question 2

How do you calculate the Rf value in chromatography?

Answer 2

Rf value = distance traveled by pigment / distance traveled by solvent

Question 3

Why is it important to use the correct solvent in chromatography?

Answer 3

Different pigments have different solubility

Question 4

Why is it important to use the same type of paper in chromatography?

Answer 4

Different papers have different properties of adhesion

Question 5

Name four photosynthetic pigments

Answer 5

chlorophylls a and b, beta carotene and xanthophylls

Question 6

What does an absorption spectrum show?

Answer 6

It is a graph showing degree of absorption of different wavelengths of light by an individual pigment

Question 7

What does an action spectrum show?

Answer 7

A graph showing the degree to which different wavelengths affect the rate of photosynthesis

Question 8

Why do plants contain multiple photosynthetic pigments?

Answer 8

This allows them to absorb a wider range of wavelengths

Question 9

Describe the structure of a photosystem

Answer 9

An antenna complex containing accessory pigments, a reaction centre containing the primary pigment (chlorophyll a)

Question 10

What is produced by cyclic photophosphorylation?

Answer 10

ATP

Question 11

Which photosystems are involved in cyclic photophosphorylation?

Answer 11

Photosystem 1 only

Question 12

What is chemiosmosis

Answer 12

A flow of protons across membranes down a concentration gradient through the enzyme ATP synthase located in the stalked particles.

Question 13

What is produced by non cyclic photophosphorylation?

Answer 13

ATP, NADPH, O2

Question 14

Which photosystems are involved in non cyclic photophosphorylation?

Answer 14

Photosystem 1 and 2

Question 15

How does photosynthesis produce O2?

Answer 15

In photolysis, water molecules dissociate into hydrogen ions, electrons and oxygen gas. The electrons replace those lost from PS2

Question 16

Where do protons travel from and to in the light dependent reactions?

Answer 16

They are pumped against their concentration gradient from the stroma into the thylakoid space using energy from the electrons travelling down the ETC. They diffuse down their concentration gradient from the thylakoid space to the stroma through ATP synthase

Question 17

Where do the light independent reactions occur?

Answer 17

The stroma of the chloroplast

Question 18

Which enzyme fixes CO2?

Answer 18

RUBISCO ribulose bisphosphate carboxylase

Question 19

Put these molecules in the calvin cycle in order: GP RuBP TP

Answer 19

RuBP GP TP

Question 20

How is GP converted into TP?

Answer 20

It is reduced by NADPH and energy is provided by ATP

Question 21

How many TP leave the calvin cycle to become glucose?

Answer 21

One in every six

Question 22

Which factors can limit the rate of photosynthesis?

Answer 22

Temperature, CO2 concentration, Light intensity. Also levels of magnesium and nitrate