7.1 & 7.2 Inheritance & Hardy-Weinberg

Question 1

Gene

Answer 1

A section of DNA that codes for ONE POLYPEPTIDE

Question 2

Locus

Answer 2

The position of genes on a chromosome

Question 3

Haploid

Answer 3

A cell with one member of each homologous pair of chromosomes

Question 4

Diploid

Answer 4

A cell with homologous pairs of chromosomes

Question 5

Genotype

Answer 5

The combination of alleles belonging to a particular organism

Question 6

Phenotype

Answer 6

The characteristics an organism has, determined by its genotype and environment

Question 7

How to properly lay out Punnett squares

Answer 7

Parents’ genotypes
Parents’ gametes
Punnett square

Question 8

Codominant

Answer 8

Both alleles are expressed in an heterozygous individual

Question 9

How to tell if a disease is dominant from pedigree?

Answer 9

Both parents affected but not all kids affected

Question 10

How to tell if a disease is recessive from pedigree?

Answer 10

Unaffected parents have affected kids (so parents must be carriers)

Question 11

What is chi-squared test used for?

Answer 11

To find out if the difference between OBSERVED categorical data and the EXPECTED data is significant

Question 12

What is null hypothesis for chi-squared?

Answer 12

There is no significant difference between observed & expected data

Question 13

Degrees of freedom in a chi-squared test

Answer 13

Number of classes - 1

Question 14

Sex linked characteristics are usually caused by genes on which chromosome?

Answer 14

X

Question 15

Describe inheritance pattern of haemophilia

Answer 15

X-linked recessive

Question 16

Can men be carriers of X-linked diseases? Why/why not?

Answer 16

NO

Men only have one copy of the X chromosome so they can’t be heterozygous for a sex-linked condition

Question 17

Monohybrid inheritance

Answer 17

Looking at the pattern of inheritance of a single characteristic

Question 18

Dihybrid inheritance

Answer 18

Looking at the pattern of inheritance of two different characteristics, controlled by different genes, located on different chromosomes

Question 19

Epistasis

Answer 19

When one allele masks/alters the expression of another

Question 20

What does it mean when two genes are linked?

Answer 20

They are on the same chromosome

Question 21

Linkage: why are actual numbers not the same as expected numbers?

Answer 21

Crossing over

Question 22

Linkage: is the frequency of recombinant phenotypes within a population higher or lower than that of non-recombinant phenotypes? Why?

Answer 22

LOWER

Crossing over is a RANDOM process
Chiasmata do not form at the same locations with every meiotic division

Question 23

The relative frequency of recombinant phenotypes is dependent on…

Answer 23

the DISTANCE between linked genes

Question 24

Recombination frequency between two linked genes is _______ when the genes are ________ on the chromosome .

Why?

Answer 24

greater

further apart

This is because there are more possible locations where a chiasmata could form between the genes

Question 25

Gene pool

Answer 25

All alleles/genes in a population

Question 26

Allele frequency

Answer 26

How many times a specific allele occurs in the GENE POOL

Question 27

Hardy-Weinberg: what is p?

Answer 27

Frequency of dominant allele

Question 28

Hardy-Weinberg: what is q?

Answer 28

Frequency of recessive allele

Question 29

Hardy-Weinberg: what is p^2?

Answer 29

Frequency of homozygous dominant genotype

Question 30

Hardy-Weinberg: what is q^2?

Answer 30

Frequency of homozygous recessive genotype

Question 31

Hardy-Weinberg: how do you represent the heterozygous genotype?

Answer 31

2pq (different orientations/order of alleles!)

Question 32

The two Hardy-Weinberg equations are:

Answer 32

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

Question 33

Assumptions of Hardy-Weinberg? (5)

Answer 33

1. no mutations
2. population is isolated: no immigration/emigration
3. no selection, all alleles equally likely to be passed on to next generation
4. large population
5. random mating