Types of Mutation and Variation

Question 1

Insertion

Answer 1

Extra base pairs are inserted into the DNA sequence

Question 2

Deletion

Answer 2

Base pairs are lost from the DNA

Question 3

Duplication

Answer 3

A section of the DNA is repeated

Question 4

Translocation

Answer 4

Sections of DNA either swap places or chromosomes join together

Question 5

Point/Substitution

Answer 5

One base pair is swapped for another

Question 6

Types of point/substitution

Answer 6

• Silent
• Missense
• Nonsense

Question 7

Silent Substitution

Answer 7

The change occurs in non-coding regions of DNA so it does not affect the phenotype

Question 8

Missense Substitution

Answer 8

The codon now codes for a different amino acid

Question 9

Nonsense Substitution

Answer 9

The change codes for a STOP codon, resulting in an incomplete protein

Question 10

What are the four chemical bases of DNA?

Answer 10

• Adenine (A)
• Guanine (G)
• Cytosine (C)
• Thymine (T)

Question 11

What is DNA?

Answer 11

A double-stranded molecule made up of a sequence of pairs of four chemical bases

Question 12

What is a mutation?

Answer 12

Mutations cause new genetic variation through changes in the DNA of a cell. They can be beneficial, harmful, or neutral. They can occur spontaneously, due to mistakes during DNA replication, or be the result of environmental factors (mutagens).

Question 13

Variation

Answer 13

Existing genetic variation in an individual can be rearranged into different combinations by random assortment and crossing over (recombination) during meiosis when gametes are formed. Further variation arises due to the random fertilization of gametes during sexual reproduction. The environment can also affect the expression of genes and the resulting phenotypes