Life on Earth: Photosynthesis

Question 1

What does photosynthesis produce?

Answer 1

• Carbohydrate sugar which is stored as starch.

Question 2

What does photosynthesis require?

Answer 2

Light, CO2, water and chlorophyll.

Question 3

What is the word equation for photosynthesis?

Answer 3

Water + CO2
chlorophyll|
| sunlight
v
carbohydrate sugar + oxygen

Question 4

What is the test for oxygen gas?

Answer 4

• It relights a glowing splint.

Question 5

What can affect how quickly a plant can photosynthesise?

Answer 5

• Amount of water.
• Amount of sunlight.
• Amount of CO2.

Question 6

How can photosynthesis be measured?

Answer 6

• Counting the number of oxygen bubbles in a set time.
• Measuring the vol. of oxygen produced in a minute.

Question 7

What are the 3 main limiting factors of photosynthesis?

Answer 7

• Light intensity
• CO2 concentration
• Temperature

Question 8

Why does the rate of photosynthesis drop at 30 degrees C?

Answer 8

It’s enzyme controlled and enzymes become denatured at high temperatures.

Question 9

What are the two stage names of photosynthesis?

Answer 9

Stage 1: Light Reactions
Stage 2: Carbon Fixation

Question 10

Describe stage 1 of photosynthesis

Answer 10

• Light energy is trapped by chlorophyll in the chloroplasts and converted into ATP.
• Light energy splits water into oxygen and hydrogen.
• Oxygen is released into the air as a waste product.

Question 11

Describe stage 2 of photosynthesis.

Answer 11

• Using ATP, carbon dioxide is ‘fixed’ with hydrogen in a series of reactions to produce sugar.

Question 12

Where does photosynthesis occur?

Answer 12

Chloroplasts

Question 13

What can sugar be used as?

Answer 13

• Energy source for respiration.
• Made into starch.
• Made into cellulose.