Section 3- Photosynthesis

Question 1

Define autotroph

Answer 1

An organism that can make its own food

Question 2

Define a heterotroph

Answer 2

An organism that is unable to make its own food

Question 3

What is the function of ATP

Answer 3

Immediate source of energy in a cell

Question 4

Describe the structure of a molecule of ATP

Answer 4

Adenine
Ribose sugar
Three phosphate groups

Question 5

How is ATP broken down

Answer 5

By the enzyme ATPase into ADP and pi

Question 6

By what process is ATP broken down by

Answer 6

Hydrolysis

Question 7

What are photosynthetic pigments

Answer 7

Coloured substances that absorb light energy needed for photosynthesis

Question 8

Name the primary photosynthetic pigment found in most chloroplasts

Answer 8

Chlorophyll a

Question 9

Name three biological processes in plants that need energy

Answer 9

Photosynthesis
Active transport
DNA replication
Cell division

Question 10

Describe and explain three ways in which chloroplast is adapted to its function

Answer 10

Chloroplast envelope keeps reactants close to reactant site
Thylakoids have large surface area- lots of light to be absorbed
Storms contains all enzymes, sugars and organic acids for light independent reaction

Question 11

Where in the chloroplast does the light dependent reaction take place

Answer 11

Thylakoids membrane

Question 12

Which products of the light dependent reaction are needed for the light independent reaction

Answer 12

ATP

Reduced NADP

Question 13

What is photo-phosphorylation

Answer 13

Adding a phosphate group using light

Question 14

What is an electron transport chain

Answer 14

A chain of proteins through which excited electrons flow

Question 15

Name photo systems involved in non-cyclic photo phosphorylation and cyclic and what are the products

Answer 15

Non : ps1 and ps2, ATP, reduced NADP, Oxygen

Cyclic: ps1, ATP

Question 16

What is the role of carbon dioxide in the Calvin cycle

Answer 16

Combined with ribulose biphosphate to make glycerate phosphate

Question 17

Describe the role of ATP in the Calvin cycle

Answer 17

Needed for the reduction of GP to TP

Needed for regeneration of RuBP from TP

Question 18

Explain why a low light intensity decreases the rate of the Calvin cycle

Answer 18

Less NADPH AND ATP
Conversion of GP to TP is slow
GP levels rise
TP and RUBP levels fall

Question 19

Describe how low temperature would affect Calvin cycle

Answer 19

Reactions catalysed by enzymes
Slow
Levels of RuBP, GP, TP will fall

Question 20

Describe how low concentration of carbon dioxide will affect the Calvin cycle

Answer 20

Conversion of RuBP to GP is slow
Less co2 to combine with RuBP
RuBP levels will rise as it isn’t being used up
GP and TP will fall as being used to make RuBP but aren’t remade