Key Definitions

Question 1

Allele

Answer 1

Any of two or more variants of a gene that have the same relative position on homologous chromosomes and are responsible for alternative characteristics

Question 2

Allele frequency

Answer 2

The percentage of a population of a species that carried a particular allele on a given chromosome

Question 3

Chiasma

Answer 3

The point at which paired chromosomes contact during crossing over

Question 4

Continuos variation

Answer 4

Variation within a population in which a graded series of intermediate phenotypes falls between the extremes (I.e human height)c

Question 5

Crossing over

Answer 5

A process occurring during meiosis where in two chromosomes pair up and exchange segments of their genetic material

Question 6

Diploid

Answer 6

A cell that contains two complete sets of chromosomes, one from each parent (I.e on humans, somatic cells and diploid as they contain 46 chromosomes)

Question 7

Discontinuous variation

Answer 7

Variation within a population in which few or no intermediate phenotypes fall between the extremes (I.e human blood groups)

Question 8

Heterozygous

Answer 8

An individual with two different alleles for a single trait

Question 9

Homozygous dominant

Answer 9

An organism, or cell that contains two dominant alleles for a single trait

Question 10

Homozygous recessive

Answer 10

An organism, or cell that contains two recessive alleles for a single trait

Question 11

Pure breeding

Answer 11

When 2 organisms with identical genotypes produce an organism with the same traits (I.e both parents are homozygous for a particular trait)

Question 12

Genotype

Answer 12

The set of alleles that determines the expression of a particular characteristic or trait

Question 13

Phenotype

Answer 13

The set of observable characteristics of an individual resulting from the interaction of it’s a genotype with the environment