2.4.3 - Inheritance: Key Terms

Question 1

What Is Meant By ‘Gene’?
(2 Points)

Answer 1

~ A sequence of bases on a DNA molecule that codes for a single polypeptide, resulting in a characteristic.

~ Location Of A Gene On A Chromosome -> Locus.

Question 2

What Is Meant By ‘Allele’?
(3 Points)

Answer 2

~ Different version of a gene.

~ Different alleles have a slightly different nucleotide sequence, but still occupy the same locus on a chromosome.

~ Different alleles arise by the process of mutations.

Question 3

What Is Meant By ‘Genotype’?
(3 Points)

Answer 3

~ Alleles of a gene possessed by that individual.

~ Could be represented as gg.

~ Genotype of an individual affects their phenotype.

Question 4

What Is Meant By ‘Phenotype’?
(2 Points)

Answer 4

~ Observable characteristics of an organism.

~ E.g. Brown eyes.

Question 5

What Is Meant By ‘Homozygous / Homozygote’?

Answer 5

When an individual has two identical alleles at a locus.

Question 6

What Is Meant By ‘Heterozygous / Heterozygote’?

Answer 6

When an individual has two different alleles at a locus.

Question 7

What Is Meant By ‘Homologous Pair Of Chromosomes’?

Answer 7

Is a pair of chromosomes that match in size, shape and contain the same genes at the same loci.

Question 8

What Is Meant By ‘Dominant’?
(2 Points)

Answer 8

~ Always expressed in the phenotype, no matter which other allele is present.

~ Dominant Alleles -> Shown by a capital letter.

Question 9

What Is Meant By ‘Recessive’?
(2 Points)

Answer 9

~ Only expressed in the phenotype if no dominant allele is present.

~ Recessive Alleles -> Shown by lowercase letter.

Question 10

What Is Meant By ‘Incomplete Dominance’?

Answer 10

When a trait from a dominant allele is not completely expressed over the trait produced by the recessive allele.