Genetics

Question 1

allele

Answer 1

different forms of a gene due to slightly different order of bases. eg brown eyes & blue eyes

Question 2

allele frequency

Answer 2

is a measure of the relative frequency of an allele on a genetic locus in a population

Question 3

asexual reproduction

Answer 3

reproduction only involving. Does not produce genetic variation

Question 4

Co - Dominance

Answer 4

heterozygous individuals have a phenotype the shows the phenotype of both parents

Question 5

complete dominance

Answer 5

a form of dominance in heterozygous conditions where in the allele that is regarded as dominant completely mask the effect of the allele that is received

Question 6

crossing over

Answer 6

occurs during meiosis, when the homologous chromosomes line up at the equator, sometimes they tangle, snap & exchange genetic variation\information

Question 7

Diploid

Answer 7

a cell or an organism, consisting of two sets of chromosomes, usually one set from the mother and another set from the father

Question 8

evolution

Answer 8

is the change in the characteristics of a species over several generations & relies on the processes of natural selection

Question 9

fertilisation

Answer 9

a process in sexual reproduction the involves the union of male (sperm) and female (ovum) gametes (each with a single set of haploids chromosomes) to produce a diploid zygote

Question 10

Fi (first generation)

Answer 10

the parental generation of the first set of parents crossed

Question 11

founder effect

Answer 11

is the loss of genetic variation that occurs when a new population is established by a very small number of individual

Question 12

gamete

Answer 12

sex cell of an organism eg sperm, egg, pollen, or ova

Question 13

gametic cells

Answer 13

sex cells. eg egg, cells that have half the chromosomes number. if a mutation occur in one of these cells & that cell results in a zygote, all cells in the offspring will have the mutation

Question 14

gene

Answer 14

a length of DNA that holds the instructions for a characteristics

Question 15

gene pool

Answer 15

refers to the total number of genes of every individual in a population

Question 16

genetic diversity

Answer 16

the total number of characteristic in the genetic make up of a species

Question 17

genetic drift

Answer 17

is then change in the frequency of an existing gene variant (allele) in a population due to the random change alone and not natural selection.

Question 18

genotype

Answer 18

the genetic make up of an organism

Question 19

haploid

Answer 19

when a cell has half the usual number of chromosomes

Question 20

heterozygous

Answer 20

different forms of the allele are present in the genotype eg Gg Hh

Question 21

Homozygous

Answer 21

Same from of the allele present in the genotype

Question 22

incomplete dominance

Answer 22

heterozygous individuals have a phenotype the is intermediate between the two homozygous phenotype

Question 23

lethal alleles

Answer 23

alleles that produce a gene product the kills of the offspring

Question 24

linked genes

Answer 24

genes that are located close together on the same chromosome that tend to be inherited together

Question 25

Unlinked genes

Answer 25

Genes that are located further apart on the on the same chromosome and tend to be separated during crossing over

Question 26

meiosis

Answer 26

type of cell division the produces gametes

Question 27

Multiple alleles

Answer 27

When 3 or more alternative forms of a gene the occupy the same locus

Question 28

mutation

Answer 28

a permanent change in the DNA base sequence creating a new allele

Question 29

Natural selection

Answer 29

individuals with more advantages traits are more likely to survive and reproduce and increasing these advantages alleles in the population over generations

Question 30

Phenotype

Answer 30

the physical appearance of an organism

Question 31

Population bottle neck

Answer 31

the population bottle neck produces a decrease in the gene pool of the population because many alleles, or gene variants, that were present in the original population are lost

Question 32

pure breeding

Answer 32

group of identical individuals that only produce one type of gamete due to the fact they are homozygous

Question 33

segregation

Answer 33

the process that occurs during meiosis where pairs of alleles are separated when the homologous chromosomes splits

Question 34

sexual reproduction

Answer 34

reproduction involving two parents, produces genetic variation

Question 35

somatic cells

Answer 35

body cells - eg skin cells, if a mutation occurs in these cells it will not be passed on to the next offspring

Question 36

test cross

Answer 36

a genetic cross between homozygous recessive individuals & a corresponding suspected heterozygous to determine the genotype of the latter