causes of genetic mutations

Question 1

what are point mutations?

Answer 1

changes in a single base

Question 2

what are silent mutations?

Answer 2

triplet codon changes but the amino acid doesnt

Question 3

what are the types of missense mutations?

Answer 3

conservative

non-conservative

Question 4

what are conservative mutations?

Answer 4

changes in the triplet change the amino acid but its chemically similar

Question 5

what are nonconservative mutations

Answer 5

changes in the triplet codon change the amino acid and it isnt chemically similar

Question 6

what are nonsense mutations?

Answer 6

leads to premature stopping of the amino acid sequence by coding for a stop codon

Question 7

what is a frameshift mutation?

Answer 7

where a single base is added or deleted from the DNA sequence - changes the reading frame

Question 8

what are the types of chromosomal mutations?

Answer 8

deletions
duplications
inversions
translocations

Question 9

what are chromosomal inversions?

Answer 9

when part of a chromosome breaks off and its added on backwards

Question 10

what are chromosomal translocations?

Answer 10

when part of a chromosome breaks off and attaches to a different chromosome

Question 11

what is an example of a disease caused by a frameshift mutation?

Answer 11

Tay Sachs

Question 12

give examples of chromosomal mutations

Answer 12

Cri du chat - partial short arm deletion
Di George syndrome - partial long arm deletion
Charcot Marie Tooth disease - duplication
XX male syndrome - translocation
Turners - monosomy
Klinefelters - non-disjunction

Question 13

what causes genetic mutations

Answer 13

spontaneous

induced (environment)

Question 14

what are mutagens?

Answer 14

agents that cause genetic mutations

Question 15

give examples of mutagens

Answer 15

phyical - UV light, radiation and heat
chemical - nicotine, pesticides and methane
biological - bacteria and viruses
radiation - direct and indirect
smoking
infectious agents

Question 16

what infectious agents can cause disease and what disease do they cause?

Answer 16

HPV - cervical cancer

Helicobacter pylori - stomach cancer

Question 17

give an example of a point mutation

Answer 17

sickle cell anaemia

Question 18

what mutation occurs in sickle cell?

Answer 18

glutamic acid –> valine

Question 19

what is non-disjunction?

Answer 19

when chromosomes fail to separate properly

Question 20

what is the only monosomy to produce viable offspring?

Answer 20

turner’s

Question 21

what happens in XX male syndrome?

Answer 21

Translocation of SRY gene from Y chromosome to X chromosome

Question 22

what spontaneous mutations can occur?

Answer 22

depurination - loss of purine base
deamination
tautomeric shift - repositioning of H atom

Question 23

what effect can direct radiation have?

Answer 23

forms a pyrimidine dimer

Question 24

what indirect effect can radiation have?

Answer 24

creation of free radicals