B2- Organisms in the Environment Flashcards Preview

Biology GCSE AQA - improvement > B2- Organisms in the Environment > Flashcards

Flashcards in B2- Organisms in the Environment Deck (11):

How can leaves be tested for presence of starch?

Iodine test- The iodine will turn blue-black on a leaf where starch is present.

A image thumb

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?

-Light (Intensity).


-CO2 Concentration.


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).