Photosynthesis

Question 1

What are the raw materials for photosynthesis?

Answer 1

• CO2 (6x)

- H20 (6x)`

Question 2

What are the products of photosynthesis?

Answer 2

• Glucose (1x)

- O2 (6x)

Question 3

How many membranes surround a chloroplast?

Answer 3

2.

Question 4

What happens to the glucose produced from photosynthesis?

Answer 4

Some is used immediately for cellular respiration (creating ATP) whilst some is stored as carbs / fats in roots, seeds and fruits.

Question 5

Thylakoids form stacks called what?

Answer 5

Grana.

Question 6

What is the balanced chemical equation for photosynthesis?

Answer 6

6CO2 + 6H2O -> C6H12O6 + 6O2

Question 7

Where are most photosynthetic cells in plants found?

Answer 7

Leaf.

Question 8

Which organisms contain chloroplasts?

Answer 8

Plants and some algae.

Question 9

Stacks of thylakoids (grana) are connected by what?

Answer 9

Lamella.

Question 10

What is the word equation for photosynthesis?

Answer 10

Carbon dioxide + Water -> Glucose + Oxygen

Question 11

What are the constituents of the chloroplast envelope?

Answer 11

Inner membrane and Outer membrane.

Question 12

Describe the structure of the chloroplasts:

Answer 12

• Chloroplast envelope (inner & outer membranes).
• Thylakoids.
• Grana (stacks of thylakoids).
• Lamella.
• Matrix
• Ribosomes (70S).
• Lipid droplet.
• Starch grain.

Question 13

What is the significance of having a double membrane for the chloroplast?

Answer 13

The chloroplast can carry out photosynthetic reactions without interference from chemicals in the cytoplasm.

Question 14

How is a leaf adapted to make photosynthesis more efficient?

Answer 14

• Large surface area that absorbs as much sunlight as possible.
• Thin, as most light is absorbed in the first few micrometres of leaf.
• Transparent cuticle and epidermis letting light through to photosynthetic mesophyll cells beneath.
• Long, narrow upper mesophyll cells packed with chloroplasts.
• Network of xylem brining water to leaf cells, and phloem carrying sugars produced.

Question 15

What is the site of the light independent reaction?

Answer 15

Stroma.

Question 16

What are the different stages in the light independent reaction?

Answer 16

Carbon fixation.
Reduction of GP to TP.
TP converted to organic substances.
Regeneration of RuBP.

Question 17

Explain the process of carbon fixation:

Answer 17

• CO2 from the atmosphere diffuses into the leaf through stomata and dissolves into water around mesophyll cells then into stroma of chloroplasts.
• CO2 reacts with RuBP to produce a 6C molecule, this is catalysed by the RuBisCo enzyme.
• Produces 2 molecules of GP.

Question 18

Explain the process of GP to TP:

Answer 18

Reduced NADP is used to reduce GP to TP using energy from ATP.

Question 19

Explain the conversion of TP to organic substances:

Answer 19

Some TP is converted to organic substances such as glucose.

Question 20

Explain the process of RuBP regeneration:

Answer 20

Most of the TP is used to regenerate RuBP using ATP, 1/6th of the TP is used to make glucose whilst 5/6ths are used to make RuBP.

Question 21

Where does the Calvin Cycle occur?

Answer 21

Stroma of the chloroplasts.