Photosynthesis

Question 1

Photosynthesis

Answer 1

Using water, carbon dioxide and sunlight to make energy in a plant

Question 2

Symbol equation for photosynthesis

Answer 2

6CO₂ + 6H₂O —₋> C₆H₁₂o₆ + 6O₂

Question 3

Endothermic or exothermic?

Answer 3

Endothermic - takes energy in from the surroundings because the bonds broken between carbon dioxide and water is more than the energy released.

Question 4

Word equation for photosynthesis

Answer 4

Carbon dioxide + water —(sunlight)—> glucose + oxygen

Question 5

Adaptations of the leaf

Answer 5

• large surface area of leaf to absorb more light
• most leaves are thin so distance for diffusion of gases is short
• veins for xylems to give water, and phloem to remove products
• air spaces that allow carbon dioxide to get in and oxygen out
• guard cells that open and close for gas exchange
• palisade cells at the top to absorb most sunlight

Question 6

Uses for glucose

Answer 6

• forms starch, (insoluble) which is storage form of a carbohydrate
• forms lipids for storage in seeds
• with nitrates to form amino acids, for proteins
• forms cellulose to build and strengthen cell walls

Question 7

Limiting factors

Answer 7

Carbon dioxide concentration, temperature, light intensity and amount of chlorophyll

Question 8

Compensation point

Answer 8

When the rate of respiration = rate of photosynthesis on a graph which shows CO2 uptake/ oxygen produced.

Question 9

How to stop light being a limiting factor

Answer 9

Use greenhouses made out of glass, position plant to absorb more light, use artificial lighting to be brighter and mimic a plant’s growing season.

Question 10

How to stop carbon dioxide being a limiting factor

Answer 10

Use carbon dioxide waste from other industrial processes, use a paraffin heater, use mycelium which produces CO2 through respiration, use liquid CO2

Question 11

How can farmers use water to increase yield?

Answer 11

Spraying water on plants to keep humidity high, use hydroponics

Question 12

What are hydroponics?

Answer 12

Growing plants in a porous material (not soil) and allowing water containing nutrients to filter through it. Optimises mineral ions

Question 13

How to prevent temperature being a limiting factor

Answer 13

Use a heating system, use a cooling system so the enzymes don’t denature and slow down photosynthesis.