Chapter B8- Photosynthesis

Question 1

How do plans make their food?

Answer 1

Photosynthesis

Question 2

What is the equation do photosynthesis?

Answer 2

Cabin dioxide+water

———>
Light
———>

Glucose+oxygen

Question 3

What is the energy transfer in photosynthesis?

Answer 3

From the environment to the chloroplasts by light

Question 4

How is the energy transferred for photosynthesis?

Answer 4

Carbon dioxide from the air and water from the soil is made into a simple sugar called glucose, with a by product of oxygen

Question 5

What kind of reaction is photosynthesis?

Answer 5

Endothermic

Question 6

How is glucose used in the plant?

Answer 6

Used for respiration

Stored

Question 7

How are leaves adapted for photosynthesis?

Answer 7

Most leaves area broad- this gives them a big surface area
Most leaves are thin- diffusion distance is short
They contain chlorophyll to absorb light
They have veins-bring water in the xylem cells and remove products of photosynthesis in the phloem
Have air spaces that allow gas exchange
Have guard cells that regulate gas exchange

Question 8

How are algae specialised for photosynthesis?

Answer 8

Large surface area

Absorb carbon dioxide dissolved in water around them

Question 9

What are the limiting factors of photosynthesis?

Answer 9

Light
Temperature
Carbon dioxide concentration

Question 10

Why is light a limiting factor of photosynthesis?

Answer 10

Without enough light, a plant cannot photosynthesise very quickly, even if there is plenty of water and carbon dioxide

Question 11

What does increasing light intensity do to photosynthesis?

Answer 11

Boost the speed of photosynthesis until the rate is slowed by another factor

Question 12

Why is carbon dioxide concentration a limiting factor for photosynthesis?

Answer 12

Even with light and heat, a plant cannot photosynthesise without carbon dioxide

Question 13

What effect does a high concentration of carbon dioxide have on photosynthesis?

Answer 13

Boosts the speed of photosynthesis until the rate is lower by another factor

Question 14

Why is temperature concentration a limiting factor of photosynthesis?

Answer 14

Plants cannot photosynthesis if it is too cold as their enzyme activity will be too low- if it is too hot, the enzymes will denature

Question 15

Explain the graphs of all three limiting factors of photosynthesis

Answer 15

Temperature- up as enzyme activity increases then down when the enzyme denatures

Carbon dioxide- goes up until it reaches a constant as photosynthesis is limited by another factor

Light intensity- goes up until it reaches a constant as photosynthesis is limited by another factor

Question 16

How do plants use glucose?

Answer 16

Turn it into cellulose which provides strength for the cell walls
They also convert it to starch, which is an energy store that is insoluble in water
To make amino acids
To make lipids

Question 17

How do some plants adapt to live in nitrate poor soil?

Answer 17

Become carnivorous plants that feed off of nutrients from the animals or insects they catch

Question 18

How are lipids used in plants?

Answer 18

Used as an energy store

Used in cell walls to make them stronger

Question 19

Why are greenhouses useful?

Answer 19

The atmosphere on the inside is warmer than on the outside- provides more light for photosynthesis
Protects the plant from harsh weather like wind and snow
Has a window which opens when the temperature gets to a certain temperature, to ensure the enzymes don’t denature
Soil and water has added minerals
Heater in which paraffin can be burnt- this keeps plants at optimum temperature and produces carbon dioxide