limiting factors in photosynthesis

Question 1

what are all the optimum conditions for photosynthesis

Answer 1

high light intensity of a certain wavelength

temperature around 25C

carbon dioxide of 0.4%

Question 2

how does high light intensity of a certain wavelength help photosynthesis

Answer 2

Light is needed to provide the energy for the light dependant reaction - the higher the intensity of the light, the more energy it provides

Only certain wavelengths of light for photosynthesis. The photosynthetic pigments chlorophyll a, chlorophyllb and carotene only absorb the red and blue light in sunlight

Question 3

why do plants look green

Answer 3

as green light is reflected

Question 4

why are temperatures around 25C optimum

Answer 4

photosynthesis involves enzymes e.g. ATP synthase, rubisco. If the temperature falls below 10C the enzymes become inactive but if the temperature is more than 45C they may start to denature

Also, at high temperatures stomata close to avoid losing too much water. This causes photosynthesis to slow down because less CO2 enters the leaf when the stomata are closed

Question 5

why is carbon dioxide at 0.4% optimum

Answer 5

carbon dioxide makes up 0.04% of the atmosphere

increasing this to 0.4% gives a higher rate of photosynthesis, but any higher and the stomata start to close

Question 6

what happens if a plant has too much water

Answer 6

it becomes water logged, reducing the uptake of minerals such as magnesium which is needed to make chlorophyll

Question 7

what can light, temperature and CO2 all also do to photosynthesis

Answer 7

limit photosynthesis

Question 8

what is the saturation point of a graph

Answer 8

the point in which a factor is no longer limiting the reaction- something else has become the limiting factor