genetics and inheritance

Question 1

gene

Answer 1

A gene is a section of DNA, that code’s for a specific protein

Question 2

genotype

Answer 2

The genetic constitution of an organism (All the alleles that an organism possesses)

Question 3

gene pool

Answer 3

All the alleles within an interbreeding population (at a particular time).

Question 4

population

Answer 4

All the individuals of the same species that occupy the same area/habitat at the same time

Question 5

phenotype

Answer 5

The organism’s phenotype is the expression of its genetic constitution and its interaction with the environment (i.e. its physical appearance)

Question 6

allele

Answer 6

The different forms / versions of the same gene
can be dominant recessive codominant

Question 7

locus

Answer 7

Different alleles for the same gene are found at the same position on the homologous chromosome; this position is referred to the locus of that gene

Question 8

homozygous

Answer 8

Most organisms are diploid, i.e. they have two copies of each chromosome and therefore two copies of a gene. If the two copies of a gene are the same allele, the organism is said to be homozygous

Question 9

heterozygous

Answer 9

If the two copies of a gene are different alleles.

Normally, when an organism has two different alleles (heterozygous), one of the alleles is expressed in the phenotype and the other is not. The phenotype is not a mixture of the two

e.g. if a person has an allele for brown eyes and one for blue eyes, only brown eye colour will be seen.

Question 10

dominant allele

Answer 10

If an allele is dominant, it will always be expressed in the phenotype regardless of whether an organism’s genotype is homozygous or heterozygous

Question 11

recessive allele

Answer 11

If an allele is recessive, it will only be expressed in the phenotype if the genotype is homozygous.

Question 12

codominant allele

Answer 12

Equally expressed in the phenotype