Bio unit 14

Question 1

variation

Answer 1

differences in the characteristics of individuals in a population

Question 2

variation may be caused by

Answer 2

• the genes they have inherited (genetic causes)
• the conditions in which they have developed(environmental causes)
• a combination of genes and the environment

Question 3

How often do mutations occur?

Answer 3

continuously

Question 4

Can a mutation lead to a new phenotype?

Answer 4

rarely

Question 5

What happens if the new phenotype is suited to an environmental change?

Answer 5

there can be a rapid change in the species

Question 6

evolution

Answer 6

change in the inherited characteristics of a population over time through a process of natural selection which may result in the formation of a new species.

Question 7

what does the theory of evolution by natural selection state?

Answer 7

all species of living things have evolved from simple life forms that first developed more than 3 billion years ago.

Question 8

what happens if two populations of one species become so different in phenotype that they can no longer breed to produce fertile offsrpring?

Answer 8

they have formed two new species

Question 9

selective breeding

Answer 9

process by which humans breed plants and animals for particular genetic characteristics.

Question 10

how long have humans been doing selective breeding?

Answer 10

thousands of years since hey first bred food crops from wild plants and domesticated animals.

Question 11

Process of selective breeding

Answer 11

• choosing parents with desired characteristic from a mixed population.
• they are bred together
• the offsrping that have the desired gene are bred together.
• This continues over many generations until the offspring show the desired characteristic.

Question 12

examples of useful characteritsics

Answer 12

• disease resistance in food crops
• Animals which produce more meat or milk
• domestic dogs with a gentle nature
• large or usual flowers.

Question 13

disadvantage of selective breeding

Answer 13

can lead to ‘inbreeding’ where some breeds are particularly prone to disease or inherited defects

Question 14

genetic engineering

Answer 14

a process which involves modifying the genome of an organism by introducing a gene from another organism to give a desired characteristic.

Question 15

how have plant crops been geneticly engineered?

Answer 15

to be resistant to diseases or to produce bigger, better fruits.

Question 16

how have bacterial cells been geneticly engineered?

Answer 16

to produce useful substances such as human insulin to treat diabetes.

Question 17

what happens in genetic engineering?

Answer 17

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

Question 18

what are crops called that have had their genes modified?

Answer 18

genetically modified (GM
) crops

Question 19

examples of GM crops:

Answer 19

• ## crops that are resistant to insect attack or herbicides

Question 20

what are the concerns about GM crops?

Answer 20

some people feel the effects of eating GM crops on human health have not been fully explored

Question 21

What is happening with modern medical research regarding GM?

Answer 21

Exploring the possibility of genetic modification to overcome some inherited disorders.

Question 22

Steps of genetic engineering

Answer 22

-enzymes are used to isolate the required gene
-this gene is inserted into a vector, usually a bacterial plasmid or virus.
-the vector is used to insert the gene into the required cells.
- genes are transferred to the cells of animals, plants or microorganisms at an early stage in their development so that they develop with desired chararcteristics.

Question 23

what is tissue culture?

Answer 23

using small groups of cells from part of plant to grow identical new plants.

Question 24

Why is tissue culture important?

Answer 24

For preserving rare plant species of comercially in nurseries.

Question 25

what is cuttings?

Answer 25

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

Question 26

what are embryo transplants?

Answer 26

splitting apart cells from a developing animal embryo before thet become specialised. Then tranplanting the identical embryos into host mothers.

Question 27

method of adult cell cloning:

Answer 27

- The nucleus is removed from an unfertilised egg cell. - The nucelus from an adult body cell, such as a skin cell, is inserted into the egg cell. - An electric shock stimulates the egg cell to divide to form an embryo. -these embryo cells contain the same genetic info as the adult skin cell. - When the embryo has developed into a ball of cells, it is inserted into the womb of an adult female to continue its development.