B2- Organisms in the Environment Flashcards Preview

Biology GCSE AQA 2016 Unit 2+3 > B2- Organisms in the Environment > Flashcards

Flashcards in B2- Organisms in the Environment Deck (15)
Loading flashcards...
1
Q

The equation for photosynthesis is…

A

Carbon dioxide + water ➡️glucose + oxygen.

2
Q

Plants need energy to make glucose. How do plants get this energy? (2 marks)

A

Photosynthesis- plants use light energy trapped by the chlorophyll in chloroplasts to change carbon dioxide and water into glucose (and oxygen).

3
Q

Describe the 3 processes of photosynthesis.

A
  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.
4
Q

How can plant growers improve plant growth?

A

Artificially controlling the environment:

  • Greenhouses with heaters and lamps.
  • Adding CO2 to the air.
  • Adding nitrate ions to the soil.
5
Q

Define dependent variable.

A

Variable being measured.

6
Q

How can quantitative data be obtained?

A
  • Random quantitative sampling using a quadrat.
  • Sampling along a transect.
7
Q

How are leaves well adapted for photosynthesis?

A
  • 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.
8
Q

The distribution of organisms is affected by environmental factors such as…

A
  • Temperature.
  • Availability of nutrients.
  • Amount of light.
  • Availability of water.
  • Availability of oxygen.
  • Availability of CO2.
9
Q

What is a transect?

A

A transect is not random. A line is marked between two points. This method supplies a lot of information about the habitat and the organisms in it.

10
Q

How can leaves be tested for presence of starch?

A

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

11
Q

How do plants use glucose?

A
  • 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.
12
Q

What are the three limiting factors of photosynthesis?

A
  • Light (Intensity).
  • Temperature.
  • CO2 Concentration.
13
Q

Define independent variable.

A

Variable being tested.

14
Q

What is a quadrat?

A

A square frame made of metal or wood which may be subdivided into a grid. If several quadrants are placed randomly in a field the investigator can count the number of a particular type of plant or animal in each quadrat.

15
Q

Describe how one should sample a plant from two habitats to collect valid data. (2 marks)

A

Use of quadrant (1) randomly placed (1).