(Paper 2) 6.3 Inheritance, Variation, and Evolution: Genetic variation

Question 1

What are the two main causes of variation within a species?

Answer 1

Genetic variation and environmental variation.

Question 2

What is genetic variation?

Answer 2

Variation caused by differences in DNA inherited from parents.

Question 3

What is environmental variation?

Answer 3

Variation caused by external factors, like climate, diet, or lifestyle.

Question 4

What is an example of a feature caused by genetic variation?

Answer 4

Blood group, eye colour, skin colour, earlobes, and biological sex.

Question 5

What is an example of a feature caused by environmental variation?

Answer 5

Scars, language, accent, and flower colour in hydrangeas.

Question 6

What is a hydrangea’s flower colour affected by?

Answer 6

Soil pH – acidic soil gives blue flowers, alkaline soil gives pink flowers.

Question 7

Give an example of a characteristic affected by both genetics and the environment.

Answer 7

Height – genes set potential, but diet affects actual growth.

Question 8

What causes all genetic variation?

Answer 8

Mutations – changes in genes or chromosomes.

Question 9

What is a mutation?

Answer 9

A change in a gene or chromosome that happens spontaneously and continually.

Question 10

Do most mutations affect the phenotypes?

Answer 10

No – most mutations have no effect on the phenotype.

Question 11

When can a mutation lead to rapid change in a species?

Answer 11

When the new phenotype gives an advantage in a particular environment.

Question 12

What is an example of a mutation affecting reproduction success?

Answer 12

A bird with a mutated feather colour might be more attractive and reproduce more.

Question 13

What is natural selection?

Answer 13

The process where organisms better adapted to their environment survive and reproduce more successfully.

Question 14

Who developed the theory of natural selection?

Answer 14

Charles Darwin.

Question 15

What does “survival of the fittest” mean?

Answer 15

The individuals best adapted to the environment are more likely to survive and reproduce.

Question 16

What is evolution?

Answer 16

The gradual change in species over time through natural selection.

Question 17

How did pollution affect the survival of light and dark peppered moths?

Answer 17

Pollution darkened tree bark, so dark moths were better camouflaged and survived more.

Question 18

Did pollution cause moths to become darker?

Answer 18

No – the dark variety already existed, but gained an advantage due to environmental change.

Question 19

What happened to the dark moth allele over time in polluted areas?

Answer 19

It became more common due to natural selection.

Question 20

What is selective breeding?

Answer 20

When humans breed plants or animals for particular genetic characteristics.

Question 21

What is another name for selective breeding?

Answer 21

Artificial selection.

Question 22

How long has selective breeding been used?

Answer 22

For thousands of years – to breed food crops and domesticated animals.

Question 23

What are the main steps of selective breeding?

Answer 23

Decide which characteristics to select.

Choose parents with those characteristics.

Breed them together.

Choose the best offspring.

Repeat over many generations.

Question 24

How many generations does selective breeding usually take?

Answer 24

Many generations – it’s a gradual process.

Question 25

Give examples of desirable traits in animals.

Answer 25

Cows that produce more milk or meat Chickens that lay large eggs Dogs with a gentle nature

Question 26

Give examples of desirable traits in plants.

Answer 26

Disease resistance High yield (e.g., wheat with lots of grain) Large or unusual flowers

Question 27

What is a gene pool?

Answer 27

The total range of genes and alleles in a population.

Question 28

What are two benefits of selective breeding?

Answer 28

Better quality/more food Safer animals (e.g., hornless cattle)

Question 29

What are three risks of selective breeding?

Answer 29

Reduced variation → vulnerable to disease Inbreeding → inherited diseases Physical defects (e.g., dogs with faulty hips)

Question 30

What happens when selective breeding reduces the gene pool?

Answer 30

There’s less genetic variation, so it’s harder to develop new varieties and resist new diseases.

Question 31

What is genetic engineering?

Answer 31

Modifying an organism’s genome by inserting a gene from another organism to produce a desired characteristic.

Question 32

What are two other terms for genetic engineering?

Answer 32

Genetic modification (GM) and genetic manipulation.

Question 33

What is a genome?

Answer 33

The entire set of genes in an organism.

Question 34

What are the steps of genetic engineering?

Answer 34

Select the desired characteristic Cut out the gene responsible Transfer and insert it into another organism Replicate the modified organism

Question 35

What is the role of enzymes in genetic engineering?

Answer 35

Enzymes are used to cut out and insert genes.

Question 36

Give two examples of genetically engineered crops.

Answer 36

Crops that are disease resistant Crops that grow larger fruits

Question 37

What is a common reason for genetically modifying crops?

Answer 37

To increase yield, improve resistance to pests, or make them nutritionally better.

Question 38

What is the benefit of replicating a genetically modified organism?

Answer 38

To produce many identical organisms with the desired characteristic.

Question 39

How is genetic engineering used to treat diabetes?

Answer 39

Bacterial cells are genetically modified to produce human insulin, used to treat people with diabetes.

Question 40

Give two examples of genetically modified crops.

Answer 40

Crops resistant to insect attack Crops resistant to herbicides

Question 41

What is the benefit of herbicide-resistant crops?

Answer 41

Weeds are killed while the crop survives, increasing yield and reducing herbicide use.

Question 42

What makes golden rice different from wild rice?

Answer 42

It contains a gene that enables production of beta carotene.

Question 43

Why is beta carotene important for humans?

Answer 43

It helps the body produce vitamin A, which is essential for good vision.

Question 44

How can golden rice help in developing countries?

Answer 44

It can prevent blindness caused by vitamin A deficiency.

Question 45

Give two concerns about genetically modified foods.

Answer 45

Possible allergic reactions or increased toxins Ethical concerns about creating new life or moving genes between species

Question 46

What are ethical issues linked to genetic engineering?

Answer 46

Some believe it's morally wrong to alter life or move genes across species.

Question 47

What future medical uses are hoped for with genetic engineering?

Answer 47

To treat inherited disorders like cystic fibrosis and Huntington’s disease.

Question 48

How is genetic engineering faster than selective breeding?

Answer 48

It directly changes genes, achieving desired traits more quickly and precisely.

Question 49

How can genetic engineering help reduce world hunger?

Answer 49

By improving crop yields and quality, especially in developing countries.

Question 50

How does herbicide resistance benefit agriculture?

Answer 50

It allows targeted weed killing, reducing overall herbicide use.

Question 51

How can genetic engineering protect crops from pests?

Answer 51

By making crops produce toxins that deter or kill insects and pests.

Question 52

How could genetic engineering reduce the spread of diseases like malaria?

Answer 52

By creating sterile insects (e.g., mosquitoes), which breed infertile offspring, reducing populations.

Question 53

What is one ecological risk of genetic engineering?

Answer 53

The engineered gene might transfer to other species, causing harm.

Question 54

Why might GM seeds be a problem in developing countries?

Answer 54

They are often expensive, making them unaffordable for poor farmers.

Question 55

What is a health concern linked to GM crops?

Answer 55

They may produce toxins or cause allergic reactions in some people.

Question 56

How might GM crops affect helpful insects?

Answer 56

Toxic pollen from GM crops may harm pollinating insects.

Question 57

What ethical issue do some people have with genetic engineering?

Answer 57

They believe it is unnatural or wrong to interfere with nature.

Question 58

What is a clone?

Answer 58

A clone is a genetically identical individual to the parent.

Question 59

Why is cloning important commercially in plants?

Answer 59

It allows rapid, cheap, large-scale production of plants with desirable characteristics.

Question 60

How does cloning relate to genetic modification?

Answer 60

Cloning allows many copies of a genetically modified organism to be produced.

Question 61

What is the simplest method of cloning plants?

Answer 61

Taking a cutting from the parent plant.

Question 62

Describe the process of cloning by cuttings.

Answer 62

Cut a branch, remove lower leaves, plant stem in damp compost, keep moist and warm, and roots grow after a few weeks.

Question 63

What helps encourage root growth in cuttings?

Answer 63

Plant hormones and covering with a clear plastic bag to keep moisture.

Question 64

What is tissue culture in plants?

Answer 64

Growing small plant pieces (explants) in vitro on sterile agar jelly with hormones and nutrients.

Question 65

Why is tissue culture more expensive than cuttings?

Answer 65

It requires sterile conditions, special equipment, and nutrients.

Question 66

What is tissue culture useful for?

Answer 66

Preserving rare plants and growing plants commercially on a large scale.

Question 67

Why does plant cloning cause fewer ethical concerns than animal cloning?

Answer 67

It has been practiced longer and is considered less controversial.

Question 68

What are the two main methods of animal cloning?

Answer 68

Embryo transplants and adult cell cloning.

Question 69

What is embryo transplant cloning?

Answer 69

An embryo is split into separate cells early in development, then each is implanted into a different surrogate mother.

Question 70

What is the purpose of embryo transplant cloning?

Answer 70

To produce genetically identical offspring (clones) from high-quality parents.

Question 71

Who was Dolly the sheep?

Answer 71

The first mammal cloned from an adult body cell, born in 1996.

Question 72

What cell was used to clone Dolly the sheep?

Answer 72

A nucleus from an udder cell.

Question 73

What is the first step in adult cell cloning?

Answer 73

Remove the nucleus from an unfertilised egg cell.

Question 74

What is the second step in adult cell cloning?

Answer 74

Insert a nucleus from an adult body cell into the egg cell.

Question 75

What stimulates the egg cell to start dividing in adult cell cloning?

Answer 75

An electric shock.

Question 76

What happens after the embryo forms in adult cell cloning?

Answer 76

The embryo is implanted into a surrogate mother to continue development.

Question 77

Why are the offspring from adult cell cloning genetically identical to the donor?

Answer 77

Because they contain the same DNA as the adult body cell used.