KA3- Photosynthesis

Question 1

What is photosynthesis?

Answer 1

Photosynthesis is an enzyme controlled process where green plants make sugar and oxygen using sunlight, water and carbon dioxide carried out in the chloroplast of green plants.

Question 2

Photosynthesis word equation?

Answer 2

Carbon dioxide + Water —> Oxygen + Glucose

Question 3

What are the two stages of photosynthesis?

Answer 3

Light reactions (light dependant)
Carbon fixation (temperature dependant)

Question 4

Stage 1

Answer 4

Light reactions

           Light energy
                    |                                                          / diffuses out of leaf cell ADP+P  \ -Chlorophyll-water = hydrogen and oxygen
 ATP  /                                               /
    \                                                   /
        Passed onto second stage

Light energy in sun is trapped by chlorophyll in chloroplasts and converted to chemical energy, used to generate ATP. Water is used to produce hydrogen and oxygen. Oxygen diffuses out the leaf cell a d hydrogen is passed onto the second stage.

Question 5

Stage 2

Answer 5

Carbon fixation

Hydrogen ATP
\ ———>
\ \
<———/
/ \
Carbon Sugar
Dioxide

The hydrogen from stage 1 is joined with carbon dioxide using chemical energy from the ATP from stage 1 to produce sugar.
Affected by temperature and pH because it is an enzyme controlled reacrion

Question 6

3 possible fates for the sugar produced by photosynthesis

Answer 6

Glucose immediately used for respiration to release energy
Starch energy store
Cell walls cellulose

Question 7

Limiting factors in photosynthesis

Answer 7

Light intensity
Carbon dioxide concentration
Temperature

Question 8

How do you know what the limiting factor is in a graph?

Answer 8

The kurb is the label and the straight line is something else