GENETIC VARIATION AND CHANGE

Question 1

MEIOSIS

Answer 1

Cell division for the formation of gametes

Question 2

SEGREGATION

Answer 2

When homologous pairs organise side by side during meiosis

Question 3

INDEPENDENT ASSORTMENT

Answer 3

The random arrangement of homologous pairs of chromosomes during meiosis

Question 4

CROSSING OVER

Answer 4

When homologous chromosomes pair up during meiosis

Question 5

COMPLETE DOMINANCE

Answer 5

One allele completely masks the expression of another allele. A heterozygous individual will show the phentoype of the dominant allele

Question 6

INCOMPLETE DOMINANCE

Answer 6

When alleles do not show complete dominance over each so that heterozygous genotypes produce phenotypes which display a mixture of each form of the trait

Question 7

CODOMINANCE

Answer 7

When a gene has more than one dominant allele, so that in heterozygous individuals both forms are expressed equally in the phenotype

Question 8

MULTIPLE ALLELES

Answer 8

When there are more than 2 alleles for a characteristic

Question 9

LETHAL ALLELE

Answer 9

Lethal alleles are those that cause the death of the organism, and are usually the result of a mutation

Question 10

TEST CROSS

Answer 10

When an individual displaying the dominant trait is crossed with a homozygous recessive individual in order to determine its genotype

Question 11

LINKED GENES

Answer 11

Whem genes for different chracteristics are found on the same chromosome and are therefore distributed together during meiosis

Question 12

GENE POOL

Answer 12

The collective number, type and variety of all the genes present in a population

Question 13

GENETIC VARIATION/ BIODIVERSITY

Answer 13

A measure of the different genetic combinations in a gene pool

Question 14

MIGRATION

Answer 14

The movement of individuals from one population to another (or to create a new population)

Question 15

GENE FLOW

Answer 15

The exchange of genes/ alleles between populations due to migration

Question 16

NATURAL SELECTION

Answer 16

The process where alleles which produce environmentally favourable phenotypes have a higher probability of being inherited than other alleles

Question 17

SELECTION PRESSURE

Answer 17

An environmental factor hich causes some phenotypes to be more favourbale for survival than others

Question 18

GENETIC DRIFT

Answer 18

The random change in allele frequencies in a gene pool, which is generally accelerated in smaller populations

Question 19

MUTAGEN

Answer 19

A factor which increases the likelihood of a mutation occurring

Question 20

SOMATIC MUTATION

Answer 20

A mutation which occurs in a normal body cell and is not inherited

Question 21

GAMETIC MUTATION

Answer 21

A mutation which occurs in a gamete and is possibly inherited

Question 22

BOTTLENECK EFFECT

Answer 22

The change in genetic variation in a population as a result of mass death of the majority of individuals

Question 23

FOUNDERS EFFECT

Answer 23

The change in genetic variation in a small population which has migrated from a larger parent population

Question 24

DIHYBRID CROSS

Answer 24

A genetic cross determining the likelihood of inheritance for two traits which independently assort

Question 25

HAPLOID

Answer 25

A cell with a half number (n) of chromosomes