How can leaves be tested for presence of starch?
Iodine test- The iodine will turn blue-black on a leaf where starch is present.
Describe the 3 processes of photosynthesis.
1. CO2 taken in by leaves, water taken up by roots.
2. Chlorophyll traps light energy needed for photosynthesis.
3. This energy is used to convert CO2 + water to glucose.
How are leaves well adapted for photosynthesis?
-Large surface area to absorb light and CO2.
-Flat shape therefore short diffusion distance.
-Many chloroplasts in palisade layer to trap maximum amount of light.
-Lots of stomata to allow CO2 to diffuse into cell for use in photosynthesis.
What are the three limiting factors of photosynthesis?
The equation for photosynthesis is...
Carbon dioxide + water ➡️glucose + oxygen.
How do plants use glucose?
-Converted into insoluble starch/fats and oils for storage.
-Growth➡️Cellulose for cell wall.
-Growth➡️To produce proteins➡️Need nitrates from soil to make proteins.
How can plant growers improve plant growth?
Artificially controlling the environment:
-Greenhouses with heaters and lamps.
-Adding CO2 to the air.
-Adding nitrate ions to the soil.
The distribution of organisms is affected by environmental factors such as...
-Availability of nutrients.
-Amount of light.
-Availability of water.
-Availability of oxygen.
-Availability of CO2.
Define independent variable.
Variable being tested.
Define dependent variable.
Variable being measured.
Plants need energy to make glucose. How do plants get this energy? (2 marks)
Photosynthesis- plants use light energy trapped by the chlorophyll in chloroplasts to change carbon dioxide and water into glucose (and oxygen).