B6 Revision cards

B6 Revision Questions

Higher only questions are in bold

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Question 1

• What is the size of a bacterium compared to a plant or animal cell?

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Answer 1

• A bacterium is about 10 times smaller ( a few micrometres)

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Question 2

• List the uses of bacteria

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Answer 2

• Yoghurt

• Cheese

• Fermenters to make many useful substances eg insulin

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Question 3

• What are the four different shapes of bacteria?

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Answer 3

• Rod shaped

• Curved rod

• Spherical

• spiral

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Question 4

• How do bacteria reproduce?

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Answer 4

• Asexual reproduction called binary fission where the bacterium splits into 2

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Question 5

• Some bacteria are producers, how do they feed?

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Answer 5

• Some bacteria that are producers use light energy for photosynthesis, others use chemicals such as hydrogen sulphide or ammonia to make their own food.

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Question 6

What is aseptic technique?

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Answer 6

• When handling bacteria:

• Wear disposable gloves

• Wash hands before and after working with bacteria

• Disinfect work areas

• Sterilise equipment before and after use

• Replace all lids on containers

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Question 7

• What problems are caused by the rapid reproduction of bacteria?

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Answer 7

• Food spoilage

• Inside the body, diseases such as food poisoning, cholera, whooping cough, typhoid, tetanus

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Question 8

• What is the use of a flagellum, cell wall and DNA in a bacterium?

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Answer 8

flagellum – allows bacterium to move

cell wall – keeps the shape and prevents bursting

DNA – controls activities and replication of the bacterium

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Question 9

• Which kingdom is yeast included in?

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• fungus

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Question 10

• How is yeast similar to but different from a plant cell?

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Answer 10

• Yeast has a cell wall and a vacuole but is different because it has no chloroplasts

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Question 11

• How does yeast reproduce?

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Answer 11

• Yeast reproduces asexually by budding

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Question 12

• What is a virus made up of?

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Answer 12

• Viruses are made up of a protein coat containing a strand of genetic material

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Question 13

• What are the optimum conditions for the growth of yeast?

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Answer 13

• Food source

• Optimum pH

• Optimum temperature

• Removal of waste products

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Question 14

• What happens to the rate of growth in yeast when the temperature rises by 10°C?

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Answer 14

• The rate of reaction would double until the optimum temperature when enzymes would begin to denature and the yeast would die

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Question 15

• How do viruses reproduce?

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Answer 15

• Viruses reproduce inside cells:

• Virus attaches to the cell

• Virus injects genetic material into the cell

• Viral DNA enters the nucleus

• mRNA is made which travels to the ribosomesto build proteins

• The host cell dies and splits open releasing many viruses

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Question 16

• What is the name for a harmful microorganism?

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Answer 16

• A pathogen

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Question 17

• Give an example of a disease caused by a bacterium, virus and fungus

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Answer 17

• Bacterium – cholera, food poisoning

• Virus – flu, chickenpox

• Fungus – athlete’s foot

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Question 18

• What are the stages in an illness?

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Answer 18

• Pathogen enters the body

• Incubation period – pathogen numbers increase

• Pathogen makes harmful toxins

• Symptoms appear, fever, high temperature

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Question 19

• How are diseases spread?

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Answer 19

• Contact eg sexually transmitted diseases

• Droplet infection – sneezing etc eg flu

• Contaminated water eg cholera

• Contaminated food eg food poisoning (salmonella)

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Question 20

• What is an epidemic and a pandemic?

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Answer 20

• Epidemic – out break of a disease within a population

• Pandemic – a disease that spreads across the world

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Question 26

what is the problem of overuse of antibiotics?

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Answer 26

• Bacteria have become resistant to diseases

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Question 27

• What did Louis Pasteur discover?

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Answer 27

• ‘germ theory of disease’, bacteria in the air make food decay

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Question 28

• What did Lister discover?

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Answer 28

• Antiseptics killed microorganisms in infected wounds

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Question 29

• What did Fleming discover?

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Answer 29

• Antibiotics. He found that penicillin killed bacteria

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Question 30

• How does resistance arise in bacteria?

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Answer 30

• Mutations give some an advantage

• Bacteria pass DNA to other bacteria passing on resistance

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Question 31

• How can resistance in bacteria be slowed down?

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Answer 31

• Only prescribe antibiotics when needed

• Complete the whole course of antibiotics

• Hand hygiene etc between patients in hospital

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Question 32

• What are the uses of bacteria?

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Answer 32

• Yoghurt, silage, cheese, vinegar, compost

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Question 33

• What is fermentation?

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Answer 33

• When yeast respires anaerobically to form ethanol and carbon dioxide

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Question 34

• What are the stages in yoghurt production?

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Answer 34

• Pasteurise milk at 95°C

Add bacterial culture and incubate at 46°C

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Question 35

• How are spirits made?

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Answer 35

• by distillation

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Question 36

• How are different flavoured wines made and why do they contain different amounts of alcohol?

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Answer 36

• Using different strains of yeast that have different tolerances to alcohol

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Question 37

• What is a biofuel?

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Answer 37

Fuel made from a organic material eg biogas and wood

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Question 38

• What is biogas?

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Answer 38

A mixture of gases usually 60% methane and 40% carbon dioxide with traces of hydrogen, nitrogen and hydrogen sulphide

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Question 39

• what is the best temperature for biogas production?

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Answer 39

• 45°C

• Above this temperature enzymes denature

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Question 40

• What is biogas used for?

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Answer 40

• To make enzymes used in respiration and photosynthesis

• So they don’t have discoloured leaves and poor fruit/flower growth

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Question 41

• Why do plants need phosphates?

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Answer 41

• To generate electricity

• To produce hot water and steam

• As a fuel for vehicles

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Question 42

• What are the advantages of biofuels?

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Answer 42

• Recycles carbon dioxide used by plants

• No particulates are formed

• Alternative to fossil fuels

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Question 43

• What are the disadvantages of biogas?

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Answer 43

• May use large areas of land that could be used for food production

• Destroys natural habitats and reduces diversity

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Question 44

• What is soil made up of?

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Answer 44

• Mineral particles

• Living organisms

• Decaying remains of organisms

• Air

• Water

• Dissolved minerals

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Question 45

• Why do plants grow in soil?

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Answer 45

• Absorb water

• Absorb minerals

• anchorage

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Question 46

• What are the advantages/disadvantages of sandy soil?

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Answer 46

• Large particles so drains well

• Big air spaces

• Minerals may leach away

• Soil dries out quickly

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Question 47

• What are the advantages/disadvantages of a clay soil?

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Answer 47

• Small particles mineral rich

• Easily water logged

• Little air

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Question 48

• What is a loam soil?

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Answer 48

• Contains clay and sand

• Large amounts of humus that retain water, add minerals and create air spaces

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Question 49

• How can soils be improved?

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Answer 49

• Add sand to clay to improve drainage

• Add humus to sandy soils to retain water

• Aerate the soil by adding sand, humus and ploughing to allow oxygen for roots and animals

• Add lime to acid soils to neutralise them

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Question 50

• How do earthworms improve soil structure?

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Answer 50

• Burrows aerate the soil and allow drainage

• Burrows mix the soil layers

• Moving organic materials from the surface into the soil forms humus

• Adds chalk from its digestive gland to neutralise soil

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