gene mutations and cancer

Question 1

What are gene mutations?

Answer 1

Changes in the sequence of nucleotide bases in DNA

Question 2

When do gene mutations occur?

Answer 2

Spontaneously

Question 3

Which process can mutations occur in?

Answer 3

DNA replication

Question 4

What is the mutation rate increased by?

Answer 4

Mutagenic agents - X rays, benzene

Question 5

What can mutations result in?

Answer 5

Different amino acid sequence in the polypeptide that the gene codes for

Question 6

Why can this happen?

Answer 6

Altered DNA sequence codes for a different amino acid sequence

Question 7

Why might mutation not affect the amino acid sequence?

Answer 7

Degeneracy

Question 8

What is frame shift?

Answer 8

When the mutation changes the nature of all base triplets from the mutation

Question 9

What are the mutations?

Answer 9

Substitution, deletion, addition, duplication, inversion, translocation

Question 10

What happens in substitution?

Answer 10

Replacement of one or more bases by one or more different bases

Question 11

What may this result in?

Answer 11

A non-functioning protein, degeneracy so the polypeptide is unchanged

Question 12

What is deletion?

Answer 12

Removal of one or more bases

Question 13

What does this result in?

Answer 13

Frame shift, non-functional protein

Question 14

What is addition?

Answer 14

Adding of one or more bases

Question 15

What does this result in?

Answer 15

Frame shift

Question 16

What is duplication?

Answer 16

One or more bases are repeated

Question 17

What is inversion?

Answer 17

Where a sequence of bases is reversed

Question 18

What is translocation?

Answer 18

Sequence of bases is moved from one location in the DNA to another part of the genome

Question 19

What is the rate of cell division controlled by?

Answer 19

Proto-oncogenes, tumour suppressor genes

Question 20

What are proto-oncogenes?

Answer 20

Genes that stimulate cell division

Question 21

What are tumour suppressor genes?

Answer 21

Genes that code for slow cell division

Question 22

What can mutations in these genes cause?

Answer 22

Rapid uncontrolled cell division

Question 23

What is a mutated proto-oncogene called?

Answer 23

Oncogene

Question 24

What happens when they are mutated?

Answer 24

Stimulates cells to divide too quickly

Question 25

What happens when tumour suppressor genes are mutated?

Answer 25

Tumour suppressor protein is not made or is non-functional

Question 26

What is cancer?

Answer 26

A group of diseases caused by alterations in the genes that regulate mitosis and the cell cycle

Question 27

What are the types of tumours?

Answer 27

Benign and malignant

Question 28

What type of tumour are cancerous?

Answer 28

Malignant

Question 29

What are the properties of a benign tumour?

Answer 29

Slower dividing, non-cancerous, remains differentiated, normal appearing cell nucleus

Question 30

What are the properties of malignant tumours?

Answer 30

Faster growing, cancerous, becomes undifferentiated, nucleus is larger and darker