3. photosynthesis

Question 1

what is the summary word equation for photosynthesis

Answer 1

CO2 + H2O —(requires light + choroplyll)-> glucose + O2

Question 2

describe the first stage of photosynthesis (the light reaction)

Answer 2

the light from the sun is trapped by chlorophyll in the chloroplasts and is converted into chemical energy which is used to generate the energy transfer molecule, ATP.

water is split to produce oxygen and hydrogen, oxygen diffuses from the cell

Question 3

describe the second stage of photosynthesis (carbon fixation)

Answer 3

carbon fixation, uses hydrogen and ATP to convert carbon dioxide from the air into glucose (sugar).

the carbon fixation reactions are catalysed by enzymes; this means that the rate of the carbon fixation reactions are affected by temperature

Question 4

what is the fate of glucose produced during photosynthesis

Answer 4

the chemical energy can be used for respiration (ATP), or the sugar can be converted into starch (storage) and cellulose (structural)

Question 5

what is a limiting factor + 3 types of limiting factors

Answer 5

a factor that holds up a process when it is in short supply. if there are any limiting factors, the rate of photosynthesis will slow down and so too will plant growth.

e.g. light intensity, carbon dioxide concentration, temperature