module 6 definitions

Question 1

genotype

Answer 1

the genetic blueprint of an organism (alleles it has for a gene)

Question 2

phenotype

Answer 2

the expression of genes in the environment

Question 3

homozygous

Answer 3

a pair of homologous chromosomes carrying the same alleles for a single gene

Question 4

heterozygous

Answer 4

a pair of homologous chromosomes carrying two different alleles for a single gene

Question 5

recessive allele

Answer 5

an allele only expressed if no dominant allele is present

Question 6

co-dominant

Answer 6

both alleles that are equally dominant, and be expressed in the phenotype

Question 6

autosomal linkage

Answer 6

genes that are located on the same chromosome (not sex-chromosome)

Question 6

dominant allele

Answer 6

an allele that will always be expressed in phenotype

Question 7

sex-linkage

Answer 7

a gene whose locus is on the X chromosome (sex chromosome)

Question 8

epistasis

Answer 8

when one gene modifies or masks the expression of a different gene at a different locus

Question 9

monohybrid

Answer 9

genetic inheritance cross of characteristics determined by one gene

Question 10

dihybrid

Answer 10

genetic inheritance cross for a characteristics determined by two genes

Question 11

gene pool

Answer 11

all the alleles of all the genes within a population at one time

Question 12

population

Answer 12

all the individuals of one species in one area at one time

Question 13

allele frequency

Answer 13

the proportion of an allele within the gene pool

Question 14

definition of continuous variation

Answer 14

characteristic with continuous values

Question 15

definition of discontinuous variation

Answer 15

characteristics with categorical values

Question 16

examples of continuous variation

Answer 16

mass and height of organisms

Question 17

examples of discontinuous variation

Answer 17

blood group

Question 18

speciation

Answer 18

occurs one original population of the same species becomes reproductively isolated. This isolation means that there are now two of the same species, but they can’t breed together to produce fertile offspring.

Question 19

allopatric speciation

Answer 19

populations are separated geographically e.g. earthquake

Question 20

sympatric speciation

Answer 20

populations can become reproductively isolated due to differences in behaviour.

Question 21

genetic bottle neck

Answer 21

caused by events that kill almost all of the population only leave a small gene pool of individuals left. (through over-hunting)

Question 22

founder effect

Answer 22

few individuals from an existing population relocated to an isolated area. (reduces genetic diversity)

Question 23

natural selection

Answer 23

organisms with phenotypes providing selective advantage are likely to survive and pass on their advantageous genes to offspring.

Question 24

artificial selection

Answer 24

humans select plants/animals with favourable characteristics an breed them together (selective breeding)

Question 25

advantages of micropropagation

Answer 25

• rapid reproduction of plants
• creates disease free plants
• can clone seedless plants e.g. grapes
• can grow plants that do not grow from seed easily

Question 26

disadvantages of micropropagation

Answer 26

• expensive
• if original cells have a viral infection, all plants produced will have virus too
• monocultures are grown and the gene pool is reduced, so all the plants are susceptible to the same diseases

Question 27

advantages of animal cloning

Answer 27

• animals with desirable characteristics will produce more offspring than with natural reproduction
• can be used to increase number of rare or endangered animals

Question 28

disadvantages of animal cloning

Answer 28

• higher rate of miscarriage when implanting embryos
• animals often have shorter life span
• unethical use of embryos

Question 29

advantages of micro-organisms in biotechnology

Answer 29

• grow rapidly
• no ethical concerns about growing microbes
• microbes are rich in protein and low in fat

Question 30

disadvantages of micro-organisms in biotechnology

Answer 30

• can produce toxins if growing conditions not carefully controlled
• must be grown in aseptic conditions
• no natural flavour, so additives must be added

Question 31

population

Answer 31

group of organisms of the same species living in the same habitat

Question 32

habitat

Answer 32

part of an ecosystem in which particular organisms live

Question 33

community

Answer 33

all the populations of different species in the same area at the same time

Question 34

ecosystem

Answer 34

the study of the relationship between organisms and their environment (abiotic/biotic factors)

Question 35

niche

Answer 35

role of an organism within the environment e.g. position on the food web

Question 36

carrying capacity

Answer 36

maximum population size an organism can support

Question 37

abiotic factors

Answer 37

non-living conditions of an ecosystem e.g. temperature, soil pH

Question 38

biotic factors

Answer 38

predation, competition

Question 39

conservation

Answer 39

human activity to help maintain biodiversity

Question 40

preservation

Answer 40

involves protecting an area by banning visitors

Question 41

advantages of conservation

Answer 41

• ethical because all organisms have right to live
• social: has physical and mental health benefits
• economic: medicines