Inheritance of genes

Question 1

In which phase of the cell cycle is genetic information replicated?

Answer 1

S

Question 2

What is the reason for Mitosis?

Answer 2

Growth and maintenance of somatic cells

Question 3

What is the main role of Meiosis?

Answer 3

To cause genetic diversity

Question 4

How can genetic diversity be achieved?

Answer 4

Independent assortment of chromosomes

Crossing over

Question 5

Define genotype

Answer 5

The genetic make-up of an individual (either as a whole or one specific genetic locus)

Question 6

Define phenotype

Answer 6

All observable characteristics of an individual or the expressed trait as a result of the genetic make-up of one (or more) specific genetic locus (loci).

Question 7

How can environmental factors effect the genotype and phenotype?

Answer 7

Can directly effect the phenotype

Can effect the genotype and consequently the phenotype

Question 8

What environmental factors can effect the genotype and phenotype?

Answer 8

Radiation
Mutagens
Chemicals that can affect cell growth
Diet
Life-style

Question 9

What is a gene?

Answer 9

A unit of heredity; a length of DNA on a chromosome that contains the code for a protein

Question 10

What is an allele?

Answer 10

An alternative form of a gene; each individual has two alleles for every gene, which can either be the same or different.

Question 11

What is the pattern for Autosomal dominant inheritance?

Answer 11

Usually someone affected in every generation

Question 12

What is the pattern for Autosomal recessive inheritance?

Answer 12

Two heterozygotes –> 25% child affected

Question 13

What is Autosomal inheritance?

Answer 13

When the gene in question is located on an autosome

Question 14

What is sex linked inheritance?

Answer 14

When the gene in question is located on a sex chromosome

Question 15

Give 2 examples of X linked recessive inherited disorders?

Answer 15

Duchenne muscular dystrophy

Haemophillia

Question 16

Define dominance

Answer 16

• A phenotypic trait is dominant when it occurs in both homo and heterozygotes.

Question 17

Define recessive

Answer 17

A phenotypic trait is recessive when it occurs only in homozygotes.

Question 18

Define co dominance

Answer 18

When both alleles are expressed in the phenotype of heterozygotes

Question 19

Define complimentation

Answer 19

More than one gene is responsible for phenotype

Question 20

What does it mean when 2 genes are linked?

Answer 20

The genes are close together on the same chromosome

Question 21

How can 2 linked genes be separated during meiosis?

Answer 21

Crossing over and recombination

Question 22

What is a genetic map?

Answer 22

The arrangement and distance between genes on a chromosome deduced from studies of recombination.

Question 23

What increases the accuracy of mapping?

Answer 23

When the genes are close together

Question 24

How can you tell how close to each other 2 loci are?

Answer 24

By the frequency of recombination between the 2 loci