B2- Organisms in the Environment Flashcards
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.
- CO2 taken in by leaves, water taken up by roots.
- Chlorophyll traps light energy needed for photosynthesis.
- 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?
- Light (Intensity).
- Temperature.
- CO2 Concentration.
The equation for photosynthesis is…
Carbon dioxide + water ➡️glucose + oxygen.
How do plants use glucose?
- Respiration.
- 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…
- Temperature.
- 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).
