W8L3 - Mutation

Question 1

What is a mutation

Answer 1

change in the nucleotide sequence of an organism’s DNA or RNA of a virus

Question 2

What is a mutagen

Answer 2

A chemical, biological or physical agent that interacts with DNA and can cause a mutation

Question 3

List small-scale mutations

Answer 3

Point mutations

Question 4

What are large-scale mutations

Answer 4

Chromosomal mutations, aneuploidy and polyploidy

Question 5

What are the types of point mutations

Answer 5

Silent, nonsense, missense

Question 6

Where are gene regulatory regions often located in

Answer 6

outside of genes

Question 7

What are silent mutations

Answer 7

Third nucleotide changed, AA(CHANGED) no effect

Question 8

What are nonsense mutations

Answer 8

First letter changed ATC (A is changed) and stop codon is created

Question 9

What is a conservative missense mutation

Answer 9

New amino acid is chemically similar, little to no impact, middle letter of codon is changed

Question 10

What is a non-conservative Missense mutation

Answer 10

Chemically different, likely changes proteins structure, middle letter of codon is changed

Question 11

What occurs in frameshift mutations

Answer 11

a nucleotide is added or removed, massive changes in amino acid sequence, nonfunctional, premature stop codon

Question 12

What chromosomal abnormalities can occur

Answer 12

deletion, inversion, duplication, translocation

Question 13

What is inversion

Answer 13

pieces of chromosome break apart, flip around and reattach itself in opposite orientation

Question 14

What occurs in translocation

Answer 14

section of one chromosome breaks off and either attaches or switches with a section of another chromosome

Question 15

What is polyploidy

Answer 15

entire set of chromosome replicated one or more times

Question 16

What is aneuploidy

Answer 16

Abnormal number of individual chromosomes (e.g 1 more chromosomes added)

Question 17

How do mutations arise?

Answer 17

external mutagens (chemical, physical or biological) or spontaneous mutations (during errors in DNA replication)

Question 18

What are causes of induced mutations

Answer 18

Physical mutagens, Chemical mutagens, biological mutagens

Question 19

Examples of physical mutagens

Answer 19

UV light from the sun

Question 20

What are examples of chemical mutagens

Answer 20

chemicals like those found in tobacco smoke, asbestos

Question 21

What are examples of biological mutagens

Answer 21

viruses, certain bacteria and transposons

Question 22

What are the cause of spontaneous mutations

Answer 22

Mistakes by DNA poly not corrected by proofreading, spontaneous changes in structure of nucleotide

Question 23

What is pyrimidine dimer formation

Answer 23

When thymine or cytosine nucleotides in DNA covalently bond with an adjacent base

Question 24

What causes pyrimidine dimer formation

Answer 24

UVB radiation from sunlight

Question 25

What do these pyrimidine dimers do

Answer 25

distort DNA helix, interfere with DNA replication and transcription

Question 26

List the 4 step processes in DNA damage repair

Answer 26

Damage recognition, incision, gap filling, ligation

Question 27

What occurs in damage recognition in DNA damage repair

Answer 27

specialised proteins bind to distorted DNA marking it for repair

Question 28

What occurs in incision in DNA damage repair

Answer 28

Endonucleases make cuts on both sides of damaged dNA and the damaged DNA is cut out

Question 29

What is Gap Filling in DNA damage repair

Answer 29

DNA polymerase fills in the gap by synthesising a new stretch of DNA

Question 30

What is ligation in DNA damage repair

Answer 30

DNA strand is sealed by an ezyme called DNA ligase