13.6 Genetics

Question 1

Gene definition

Answer 1

A section of DNA that codes fore a specific protein

Question 2

Genotype definition

Answer 2

The genetic constitution of an organism, all the alleles that an organism posseses

Question 3

Gene pool

Answer 3

All the alleles with an interbreeding population at a specific time

Question 4

Population definition

Answer 4

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

Question 5

Phenotype definition

Answer 5

The organisms phenotype is the expression of its genetic constitution and its interaction with the environment

Question 6

Allele definition

Answer 6

Different version of the same gene

Question 7

Multiple alleles definition

Answer 7

More than 2 alleles for the same gene, this produces a heirarchy of dominance

Question 8

Locus definition

Answer 8

Different alleles for the same gene are found at the same position on the homologous chromosome, this position is the locus of the gene

Question 9

Homozygous definition

Answer 9

Most organisms are diploid, they have two copies of each chromosome
If the two copies of the gene are the same allele, the organism is homozygous

Question 10

Heterozygous definition

Answer 10

If the two copies of the gene have different alleles

Question 11

Dominant allele definition

Answer 11

If the allele is dominant it will always be expressed in the phenotype

Question 12

Recessive allele definition

Answer 12

It will only be expressed in the phenotype if the genotype is homozygous

Question 13

Codominant alleles definition

Answer 13

Equally expressed within the phenotype

Question 14

Diploid definition

Answer 14

Adult cells are normally diploid, two copies of a gene

Question 15

Haploid definition

Answer 15

Gametes are haploid, one copy of a gene

Question 16

Ratio of monohybrid

Answer 16

3:1

Question 17

Ratio of codominance

Answer 17

1:2:1

Question 18

Ratio of dihybrid

Answer 18

9:3:3:1

Question 19

Ratio of epistasis

Answer 19

9:4:3
15:1
9:7
Ratio always adds up to 16

Question 20

Ratio of autosomal linkage

Answer 20

3:1

Question 21

Hardy - Weinberg equations

Answer 21

p+q=1
p^2 + 2pq + q^2= 1

Question 22

What is p^2?

Answer 22

Homozygous dominant individuals

Question 23

What is 2pq?

Answer 23

Heterozygous individuals

Question 24

What is q^2?

Answer 24

Homozygous recessive individuals

Question 25

What is p?

Answer 25

Dominant alleles

Question 26

What is q?

Answer 26

Recessive alleles

Question 27

What does hardy-weinbergs principal predict?

Answer 27

The allelic frequency from one generation to the next will remain constant if there is no:
- migration
- gene mutations
- selection

should be:
- a large population
- mating should be random

Question 28

Dominant characteristic rules

Answer 28

• affected offspring must have at least one affected parent
• unaffected offspring only have unaffected parents
• if both parents are affected and have unaffected offspring, both parents must be heterozygous

Question 29

Recessive characteristic rules

Answer 29

• unaffected parents can have unaffected offspring if they are heterozygous

Question 30

Sex linked rules for dads and daughters

Answer 30

• if a daughter is affected, her father is not, and its a recessive disease
• it is NOT sex linked

Question 31

Sex linked rules for mothers and sons

Answer 31

• if a son is affected and his mum is not, and it is a dominant disease
• it is NOT sex linked

Question 32

Linkage group definition

Answer 32

A set of genes on the same chromosome which tend to be inherited together

Question 33

Epistasis definition

Answer 33

An interaction between two genes where one allele affects the expression of another