GENETIC MUTATION

Question 1

What are the 2 types of genetic mutation?

Answer 1

Substitution - a nucleotide is replaced by another in the base sequence
Deletion - a nucleotide is removed from the base sequence

Question 2

What are the differences between the 2 types of mutation?

Answer 2

Because genetic code is degenerate, a substitution mutation although forming a different codon, will still code for the same amino acid and no change to the primary structure

A deletion causes a frameshift, affecting the codons after it, and affecting the entire amino acid sequence

Question 3

What are the 2 types of chromosome mutations?

Answer 3

Polyploidy - organisms having >2 sets of chromosomes, mainly in plants
Non-disjunction - homologous pairs fail to split during meiosis; the gamete has more/less chromosomes

Question 4

What is the process in meiosis 1?

Answer 4

Homologous chromosomes pair up, and the chromatids wrap around each other and crossing over occurs.
1 of each pair randomly goes to a daughter cell; independent segregation

Question 5

What’s the process with meiosis 2?

Answer 5

Chromatids are separated again
The daughter cells divides again, 4 haploid cells are produced

Question 6

How does crossing over work?

Answer 6

The chromatids twist around each other; portions break off and rejoin with the partner’s chromatid
This increases genetic diversity, new combinations of alleles are produced