Mutation

Question 1

What are the three mutagens?

Answer 1

Physical, chemical and biological

Question 2

What is somatic mutation?

Answer 2

Mutation in body cells

Question 3

How can mutations cause cancer?

Answer 3

Apoptosis is impaired, so cells don’t die and keep growing

Question 4

What is base pair substitution?

Answer 4

When the wrong complimentary base is added during replication.

Question 5

What are physical mutagens?

Answer 5

UV light: fuses adjacent bases and distorts DNA
X-ray: causes loss of bases creating gaps in DNA
Nuclear radiation: causes double stranded breaks in DNA

Question 6

How do biological mutagens cause mutation?

Answer 6

Bacteria can insert their DNA into a host’s genome

Question 7

What are the types of gene mutation?

Answer 7

1. Point mutation (substitution): either doesn’t alter the protein, creates a different protein or creates a stop codon (no protein at all).
2. Insertion and deletion: Causes frameshift mutation (change in the way the sequence is read)

Question 8

Effects of mutations

Answer 8

– Beneficial
– Neutral
– Deleterious

Question 9

What are the chromosomal variations?

Answer 9

Polyploidy (2n gametes)
Aneuploidy (addition or loss of one chromosome)

Question 10

What are variations in chromosomal STRUCTURE?

Answer 10

Deletion: strand breaks into two and one part is lost
Inversion: segment of chromosome is rotated 180º and reconnects
Translocation: segment breaks off and reattaches to another chromosome
Duplication: part of the chromosome is copied twice