6.2 - Mutations

Question 1

What is point mutation?

Answer 1

A small change in nitrogenous base sequence of a DNA (a single-base pair)

Question 2

Types of point mutations?

Answer 2

1. Base-pair substitution: ACA > AGA
2. Insertion: ACA > ATCA
3. Deletion: ACA > AA

Question 3

What is chromosome mutation?

Answer 3

Error that involves the entire chromosome or a large part of a chromosome (ex. nondisjunction which is the failure of homologous chromosomes or sister chromatids to separate properly during cell division)

Question 4

Sickle cell anemia

Pattern of inheritance?
What is it caused by?

Answer 4

It is autosomal recessive.

A mutation in the HBB gene causes hemoglobin molecules to be defective. A single adenine base was substituted by a thymine, causing C-shaped blood cells.

Question 5

Lactose intolerance

Pattern of inheritance?
What is it caused by?

Answer 5

It is autosomal recessive.

A mutation of the LCT gene on chromosome 2 causes those affected to not be able to digest lactose, a common sugar in milk.

Question 6

What is spontaneous mutation?

Answer 6

Occurs randomly, by accident.

Ex. Errors in cell division

Question 7

What is induced mutation?

Answer 7

Occurs because of exposure to outside factors (environmental)

Ex. UV radiation

Question 8

How do mutations lead to antibiotic resistance?

Answer 8

Treating bacteria with that specific antibiotic results in the most resistant bacteria (resistant due to gene transfer, genetic mutation, or just naturally) surviving.

These bacteria can now increase in numbers and the end result is a population of mainly antibiotic resistant bacteria.