factors affecting photosynthesis

Question 1

what is light intensity

Answer 1

level of light

Question 2

what is water stress

Answer 2

condition a plant will experience when water supply becomes limiting

Question 3

what are some limiting factors of photosynthesis

Answer 3

raw materials
light intensity
enzymes
plant turgidity
chlorophyll availability

Question 4

what does light intensity allow a plant to do

Answer 4

light opens stomata for gaseous exchnage and transpiration

also provides energy for the light dependent stage, producing atp and reducing NADP

Question 5

how does changing light intensity affect the calvin cycle

Answer 5

Glycerate phosphate cant be reduced to triose phosphate
Triose phosphate levels fall, and GP increase.
If TP levels fall, RuBP cant regenerate.

Question 6

why is it rare that carbon dioxide is a limiting factor

Answer 6

because there is so much in the atmosphere

Question 7

what are the effects of carbon dioxide as a limiting factor on the calvin cycle

Answer 7

RuBP cant accept CO2 and as a result accumulates
GP or TP cant be made

Question 8

what is the effects of temperatures of 25-30 degrees on the calvin cycle

Answer 8

sufficient water and co2 and low temp allows rate of photosynthesis to increase

Question 9

what effect do temps of 45+ have on the calvin cycle

Answer 9

enzymes become denatures, e.g. RuBisco
GP, TP reduce and eventually RuBP as it cant be regenerated due to the lack of TP.

Question 10

what effect do temps of 30+ have on calvin cycle

Answer 10

reduce growth rates.
co2 and o2 compete for the active site of RuBisco
reduces co2 accept by rubisco and reduces tp and gp production

Question 11

what are the effects of water stress

Answer 11

cells become plasmolysed instead of turgid

tissues become flaccid and will wilt
rate of photosynthesis reduces

roots cant replace water lost by transpiration

roots produce abscisic acid which is translocated to the leaves causing stomata to close