Genetic Diversity And Variation

Question 1

What is the largest source for genetic variation in mitosis ?

Answer 1

The independent segregation

Question 2

How does crossing over lead to genetic variation ?

Answer 2

1. Homolgous chromosomes will associate
2. Forming a chiasmata
3. Having an equal exchange of chromatid length
4. Forming new combinations of alleles

Question 3

How does ‘ Independent Segregation ‘ lead to genetic variation ?

Answer 3

1. The random shuffling of homologous chromosomes
2. In interphase, chromosomes will split and paternal and maternal alleles will move to opposite ends of the cell
3. After first division, different cells will have a different make-up of alleles (More/less maternal)
4. Producing a new combination of alleles

Question 4

What are the sources for genetic variation ?

Answer 4

Mutation
Meiosis (Independent seg. + Crossing over )
Random fusion of gametes

Question 5

What does genetic variation lead to ?

Answer 5

New combinations of alleles

Question 6

What does ‘Substitution mutation’ involve ?

Answer 6

The changing of one base in the dna triplet

Question 7

What is meant by a ‘ universal genetic code’ ?

Answer 7

Same 3 bases in dna triplet code for same amino acid across all organisms

Question 8

Define the term ‘ exon ‘

Answer 8

Section of dna that codes for a specific sequence and number of amino acids

Question 9

Explain the effects of an ‘ addition ‘ mutation

Answer 9

Causes all triplets to move along
Would affect all amino acids
Wouldn’t cause the change in only 1 amino acid