N4 Unit 1 Part B

Question 1

Give two useful properties of microorganisms.

Answer 1

They grow quickly and they can use a wide range of materials as a food source

Question 2

What three food products rely on the activities of yeast?

Answer 2

Beer, wine and bread

Question 3

Give the word equation for fermentation in yeast.

Answer 3

Sugar → alcohol + carbon dioxide + some energy

Question 4

Which of the products of fermentation are useful to a brewer and why?

Answer 4

Alcohol makes the beer alcoholic and carbon dioxide makes it fizzy

Question 5

Which of the products of fermentation are useful to a bread maker and why?

Answer 5

Carbon dioxide makes the bread dough rise.

Question 6

What is a biofuel?

Answer 6

A renewable fuel that can be made from biomass

Question 7

Name three types of biofuels.

Answer 7

Bioethanol, biodiesel and biogas

Question 8

Describe how bioethanol is produced.

Answer 8

Once the plant (corn or sugar cane for instance) have been harvested, yeast are allowed to digest it. Oxygen levels are kept low, they carry out fermentation and produce bioethanol.

Question 9

How is biodiesel produced?

Answer 9

A type of bacteria has been modified to allow it to produce biodiesel. It feeds on sugar from plant material and secretes the biodiesel into the vat it is growing in.

Question 10

What is biogas used for?

Answer 10

Can be used to generate electricity or for cooking.

Question 11

Give one advantage for biofuels.

Answer 11

They emit up to 70% less carbon than fossil fuels

Question 12

Give one disadvantage for biofuels.

Answer 12

Ethanol is much less efficient than other fuels and gets only about 70% of the mileage of petrol.

Question 13

Name two food products made using bacteria.

Answer 13

Cheese and yoghurt

Question 14

When making yoghurt, why is the milk heated before adding the starter culture of bacteria?

Answer 14

To kill off any unwanted microorganisms.

Question 15

Describe the lactic acid fermentation process.

Answer 15

The bacteria feed on the sugars in the milk and convert the lactose into lactic acid

Question 16

What is bioremediation?

Answer 16

Any process where a living organism (such as bacteria) is used to remove pollutants from the environment.

Question 17

What is sewage?

Answer 17

Wastewater that comes from homes, businesses, and other facilities.

Question 18

Describe how bacteria are involved in the sewage treatment process.

Answer 18

Bacteria feed on the sewage and break it down.

Question 19

What is radioactive waste?

Answer 19

Waste filled with unstable elements or radionuclides

Question 20

Describe how bacteria can be used for bioremediation of radioactive waste.

Answer 20

Bacteria can convert toxic mercuric ions to elemental mercury, which is less harmful to humans

Question 21

What is oil spill bioremediation?

Answer 21

A process that uses microorganisms to break down toxic substances in oil spills.

Question 22

What is photosynthesis?

Answer 22

A chemical reaction which allows plants to make their own food using light energy.

Question 23

What are the raw materials of photosynthesis?

Answer 23

Carbon dioxide and water

Question 24

What are the requirements of photosynthesis?

Answer 24

Light and chlorophyll

Question 25

What are the products of photosynthesis?

Answer 25

Glucose and oxygen

Question 26

Describe the role of chlorophyll.

Answer 26

Absorbs light energy.

Question 27

Describe the energy conversion which takes place during photosynthesis.

Answer 27

light energy → chemical energy

Question 28

How is the sugar made during photosynthesis stored?

Answer 28

Turned into starch

Question 29

What is a limiting factor?

Answer 29

A factor that can limit the rate of photosynthesis if it is absent or in short supply.

Question 30

What are the four limiting factors of photosynthesis?

Answer 30

Light, water, carbon dioxide and suitable temperature

Question 31

What are the raw materials of respiration?

Answer 31

Glucose and oxygen

Question 32

What are the products of respiration?

Answer 32

Carbon dioxide, water and energy

Question 33

What piece of equipment can be used to measure the rate of respiration in an organism?

Answer 33

Respirometer

Question 34

Name three factors which could affect the rate of respiration.

Answer 34

Concentration of oxygen, concentration of glucose and temperature

Question 35

What is fermentation?

Answer 35

A type of respiration which takes place in the absence of oxygen

Question 36

Give the word equation for fermentation in animal cells.

Answer 36

glucose → lactate + some energy

Question 37

What condition is caused by a build-up of lactate in the muscles?

Answer 37

Muscle fatigue

Question 38

What is an oxygen debt?

Answer 38

The amount of oxygen required to break lactate down

Question 39

Give the word equation for fermentation in plant and yeast cells.

Answer 39

glucose → carbon dioxide + alcohol + some energy

Question 40

What does aerobic mean?

Answer 40

In the presence of oxygen

Question 41

Which type of respiration releases the most energy?

Answer 41

Aerobic respiration

Question 42

Why is stem cell technology used?

Answer 42

To cure diseases

Question 43

Why is stem cell technology controversial?

Answer 43

It involves the destruction of embryos