B14: Variation & Evolution

Question 1

What is selective breeding?

Answer 1

The process by which humans breed animals for particular genetic characteristics.

Question 2

How long has selective breeding been going on for?

Answer 2

Thousands of years since they first bred food crops from wild plants and domesticated animals.

Question 3

What is the process of selective breeding?

Answer 3

Choosing parents with desired characteristics from a mixed population which are bred together.

Question 4

What are 4 examples of reasons to selectively breed?

Answer 4

Get disease resistance in foods, animals that produce more milk, domestic dogs with gentle nature and large or unusual flowers

Question 5

What is the main disadvantage of selective breeding?

Answer 5

It reduces the collection of different alleles of the population. It can also lead to inbreeding where some will be prone to diseases as their gene pool is small

Question 6

Why have plants been genetically engineered?

Answer 6

To be resistant to diseases or produce bigger and better fruit

Question 7

Why have bacterial cells been genetically engineered?

Answer 7

To produce useful substances such as insulin to treat diabetes

Question 8

What happens in genetic engineering?

Answer 8

Genes from the chromosome of humans and other organisms can be cut out and transferred to cells or other organisms

Question 9

What are some concerns about GM foods?

Answer 9

It effects the population of wild flowers and insects. They also think that the effects on human health has not been explored

Question 10

What are 3 main steps in genetic engineering?

Answer 10

Enzymes are used to isolate the required gene which is inserted into a vector. The vector is used to insert the gene into required cells and genes are transferred to the cells of animals, plants or microorganisms at early stages to they can develop desired characteristics

Question 11

What is usually a vector in genetic engineering?

Answer 11

Bacterial plasmid or virus

Question 12

What are disadvantages of gene therapy?

Answer 12

The faulty gene will be in all cells, so putting the healthy gene in all cells would be difficult.

Question 13

What would be a solution to the disadvantage of gene therapy?

Answer 13

Transferring the gene at an early stage of development, e.g. egg or embryo stage

Question 14

What are advantages of GM crops?

Answer 14

Used to make crops with more desirable crops (resistant to disease)

Question 15

What is tissue culture?

Answer 15

Using small groups of cells from part of a plant to grow identical new plants

Question 16

What is tissue culture important for?

Answer 16

Preserving rare plant species or commercially in nurseries

Question 17

What are cuttings?

Answer 17

An older, but simple method used by gardeners to produce many identical new plants from a parent plant

Question 18

What are embryo transplants?

Answer 18

The process of splitting apart cells from developing animal embryo before they become specialised, then transplanting the identical embryos into host mothers

Question 19

What are the 5 steps of adult cell cloning?

Answer 19

Nucleus is removed from unfertilised egg, nucleus from adult body cell is transferred to egg, electric shock stimulates cell division to embryo. This is then placed into the uterus of the surrogate

Question 20

What are 3 advantages of cloning via embryos, rather than selective breeding?

Answer 20

Faster, no need for 2 parents and more offspring produced

Question 21

What are 2 benefits of cloning via cuttings, rather than micropropagation?

Answer 21

Faster and no need for professional expertise or equipment

Question 22

What is evolution?

Answer 22

The process by which the inherited characteristics of a population change over time due to natural selection

Question 23

What provides evidence for evolution?

Answer 23

Antibiotic resistance and fossil records

Question 24

What are disadvantages of inbreeding?

Answer 24

Population is more prone to disease, reduces size of gene pool and rare inherited diseases are more likely to appear

Question 25

What are the steps of micropropagation?

Answer 25

Find plant with desirable characteristics and clone and take small parts of plant tissue, then sterilise. Place explants into agar dish and allow them to grow into calluses. Transfer calluses to soil to grow into plantlets, which can then be transferred to their own pots

Question 26

What nutrients are needed in agar in micropropagation?

Answer 26

Glucose for respiration and magnesium for chlorophyll