4.1.2 Rate of photosynthesis Flashcards
(15 cards)
Ways of measuring rate of photosynthesis? (3p)
- the rate of oxygen output
- the rate of CO2 output
- the rate of carbohydrate production
Factors that affect the rate of photosynthesis (4p)
- Temperature
- Light intensity
- Chlorophyll
- CO2 concentration
Variegated
Parts of leaf that aren’t green
How does variegated parts of a leaf affect photosynthesis (3p)
- Variegated parts don’t contain chlorophyll, a green pigment
- chlorophyll is needed for photosynthesis
- so make plant grow slower or possible die
Limiting factor
A variable that is in short supply and therefore prevents the rate of a process from being as fast as it could be
What happens to light intensity as distance increases?
It decreases
Inverse square law
As the distance from the light source increases, the light intensity decreases
Light compensation point
the specific light intensity at which the rate of photosynthesis equals the rate of respiration
When there is no light, why is the rate a negative number (on a graph)? (2p)
- No light means no photosynthesis can occur
- but the plant is respiring so oxygen is used up
What is the rate of respiration and photosynthesis like in the day?
- The rate of photosynthesis is greater than the rate if respiration
How is light intensity & CO2 concentration affecting the rate of photosynthesis shown on a graph
A curve before a plateau as the variable is no longer the limiting factor
How is temperature affecting the rate of photosynthesis shown on a graph
- A curve that peaks at around 40’C
Optimum temperature fir plants
40’C
Why does the rate of photosynthesis decrease after 40’C? (3p)
- Enzymes in the plant denature
- the active site on the enzyme changes shape
- active site and substrate don’t fit
How does CO2 become the limiting factor?
- Only 0.04% of CO2 in the atmosphere
