Inheritance

Question 1

Diploid

Answer 1

Cell or organisms with a pair of homologous chromosomes and hence two alleles of each gene

Question 2

Allele

Answer 2

A variation of version of a gene

Question 3

Genotype

Answer 3

Combination of all genes that an organism produces

Question 4

Phenotype

Answer 4

Physical expression of the genotype and its interaction with the environment

Question 5

Dominant allele

Answer 5

An allele that is always expressed in the phenotype

Question 6

Recessive allele

Answer 6

An allele that is only expressed when homozygous

Question 7

Codominant allele

Answer 7

When both alleles are always expressed in the phenotype, and is usually intermediate between the two

Question 8

Homo/heterozyguous

Answer 8

When alleles are the same, not the same

Question 9

Monohybrid inheritance

Answer 9

Inheritance of a characteristic controlled by a single gene

Question 10

Dihybrid in inheritance

Answer 10

Inheritance of two characteristics that are controlled by separate genes

Question 11

Epistasis

Answer 11

An interaction between genes, where the expression of one gene suppressed the expression of another gene

Question 12

When can epistasis occur?

Answer 12

When a phenotype is controlled by more than one gene

Question 13

What are the phenotypic ratios for a recessive epistatic allele, and dominant epistatic allele

Answer 13

(9:3:4) and (12:3:1)

Question 14

Autosome

Answer 14

Any chromosome that is not a sex chromosome

Question 15

Autosomal linkage

Answer 15

Genes on the same chromosome so stay together during independent assortment so inherited together

Question 16

What is the phenotypic ratio for autosomal linkage

Answer 16

(3:1)

Question 17

What does autosomal linkage mean

Answer 17

More offspring have the same genotype and phenotype as parents UNLESS crossing over occurs

Question 18

What does a closer loci on autosomal linkage mean

Answer 18

Gene more closely linked

Question 19

Homologous pair

Answer 19

Same gene loci

Question 20

Sex linkage

Answer 20

Expression of alleles located on sex chromosomes depending on the sex of the individual

Question 21

Why are males susceptible to sex linked disease

Answer 21

Only one X chromosome so cannot be carrier

Question 22

What is the normal phenotypic ratio for MHC F2

Answer 22

3:1 Dominant to recessive

Question 23

What is the normal phenotypic ratio for DHC F2

Answer 23

9:3:3:1
9 Dominant both
3 Dominant, then recessive
3 Recessive, then dominant
1 Recessive both

Question 24

What is the normal phenotypic ratio for codominance F2

Answer 24

1:2:1
Homozygous 1
2 Heterozygous
Homozygous 2

Question 25

What is the phenotypic ratio in epistasis for a recessive epistatic allele and dominant epistatic allele F2

Answer 25

9: 3:4
12: 3:1

Question 26

What is the phenotypic ratio for hetero dominant and recessive Sex Linkage

Answer 26

3: 1
1: 1