B2.2 Organisms and the Environment

Question 1

What is the light energy used for photosynthesis absorbed by?

Answer 1

Chloroplasts

Question 2

What is the glucose made from photosynthesis used for?

Answer 2

• It can be used immediately for respiration.

- It can be stored as starch for later use.

Question 3

What is the test to show that photosynthesis has taken place in a plant?

Answer 3

The iodine test.

-The iodine reacts with starch turning it from yellow to blue.

Question 4

What are the four main adaptations of leaves?

Answer 4

• Large surface area for light to fall on.
• Contain chlorophyll in the chloroplasts to absorb the light energy.
• They have air spaces allowing gas exchange.
• They have veins which bring water to the cells.

Question 5

What factors limit the rate of photosynthesis in a plant?

Answer 5

• Intensity of light
• Temperature
• CO2 level.

Question 6

How does light intensity affect the rate of photosynthesis?

Answer 6

The greater the intensity, the faster the rate of photosynthesis.

Question 7

How does temperature limit the rate of photosynthesis?

Answer 7

Photosynthesis is controlled by enzymes. The rate of photosynthesis increases with the temperature until the enzymes start to denature.

Question 8

How does the level of carbon dioxide affect the rate of photosynthesis?

Answer 8

The greater the level of carbon dioxide, the greater the rate of photosynthesis.

Question 9

What four ways do plants use the glucose they produce?

Answer 9

• Respiration
• Covert into insoluble starch for storage
• Produce fats or oils for storage
• Produce fats, proteins or cellulose for cells and cell walls.

Question 10

How do plants use glucose to make amino acids?

Answer 10

• Glucose is combined with nitrate and other mineral ions.

- The amino acids are then built up to make proteins.

Question 11

Why is glucose made into insoluble starch?

Answer 11

If glucose were stored in plant cells it could affect the way water moves in and out of cells affecting the water balance of the plant.
Starch has no affect on the water balance meaning large amounts can be stored.

Question 12

What is the purpose of making starch?

Answer 12

To provide energy for when it is dark or low light.

Question 13

What is a tuber or bulb?

Answer 13

They are large storage areas for starch.

Question 14

Why are greenhouses and poly tunnels used to grow some food?

Answer 14

The temperature inside greenhouses is higher increasing the rate of photosynthesis.

Question 15

What is hydroponics?

Answer 15

Computer controlled growing conditions for plants with ideal amounts of water and mineral ions in the soil.

Question 16

Give three advantages of using hydroponics.

Answer 16

• Turnover is fast.
• Crops are clean and unspoilt.
• No ploughing or preparing the land is needed.

Question 17

Give a disadvantage of using hydroponics.

Answer 17

The systems are expensive to set up.

Question 18

Give five factors that affect the distribution of living organisms.

Answer 18

• Temperature
• Nutrients
• Amount of light
• Availability of water
• Availability of oxygen and carbon dioxide.

Question 19

Why does temperature affect the distribution of living organisms in cold areas?

Answer 19

Only small plants can survive in cold climates which limits the number of herbivores that can survive in the area.

Question 20

Why do nutrients affect the distribution of plants?

Answer 20

Most plants struggle to survive in areas with little nutrients. Whereas Venus fly traps thrive since they get nutrients from the flies they digest.

Question 21

Why does the amount of light affect the distribution of organisms?

Answer 21

Plants are adapted to live in certain light conditions.

The breeding cycles of animals are connected to the day length.

Question 22

How is the distribution of living organisms in their environment measured?

Answer 22

• Random sampling with quadrats.

- Sampling along a transect.

Question 23

What is a quadrat?

Answer 23

A square that outlines the sample area.

Question 24

Why is sample size important?

Answer 24

Sample areas must be random to ensure the validity of the data. ie. the results reflect the distribution of organisms.

Question 25

What is the difference between using a transect and a quadrat?

Answer 25

A transect is not random.

Question 26

What is a reproducible investigation?

Answer 26

Other people can carry out the same investigation and get similar results.

Question 27

What does an investigation have to be, to be valid?

Answer 27

It must answer the question that has been asked..

Question 28

Why is it important to control variables?

Answer 28

It means other scientists can reproduce the results.

Question 29

What data can be used as evidence of environmental change?

Answer 29

The investigation must state the problems of collecting data.

Question 30

What is the equation for photosynthesis?

Answer 30

carbon dioxide + water –(light)–> glucose + oxygen