D1.3 Mutation and gene editing

Question 1

gene mutation

Answer 1

a change in the sequence of bases of a particular gene

Question 2

when do mutations occur

Answer 2

all the time and at random

Question 3

inheritance of mutations

Answer 3

Mutations present in normal body cells are not inherited, they are eliminated from the population once those cells die

Mutations within gametes are inherited by offspring, possibly causing genetic disease

Question 4

what is a mutation

Answer 4

the process of dna replication is complex and mistakes occur sometimes

Question 5

point mutation

Answer 5

change in one base in the gene sequence
can be the result of
substitution mutation
insertion
deletion

Question 6

substitution mutations

Answer 6

where one nucleotide is replaced by a different nucleotide

caused by DNA being copied incorrectly

Question 7

insertion mutations

Answer 7

addition of one or more nucleotides into a segment of dna

Question 8

deletion

Answer 8

the loss of one or more nucleotides from a segment of DNA

Question 9

Frameshift Mutations

Answer 9

A mutation in a DNA chain that occurs when the number of nucleotides inserted or deleted is not a multiple of three, so that every codon beyond the point of insertion or deletion is ready incorrectly during translation

Question 10

what can frameshift mutations be caused by

Answer 10

insertions or deletion as these processes alter the reading Frame of codons

Question 11

same sense mutation

Answer 11

change one codon for an amino acid into another codon for the same amino acid

AGC becomes AGT

Question 12

nonsense mutation

Answer 12

change a codon that codes for an amino acid into a stop codon

translation is therefore terminated before a polypeptide has been completed

stop codons - UAA, UAG, UGA

Question 13

mis sense mutation

Answer 13

alter one amino acid in the sequence of amino acid in a polypeptide

eg, sickle cell disease

Question 14

SNPs full form

Answer 14

single nucleotide polymorphisms

Question 15

what are SNPs

Answer 15

silent mutations which does not alter the amino acid sequence

when DNA from individuals humans is sequenced, large numbers of base substitutions are found that have happened at some time in the past

Question 16

where can SNPs occur

Answer 16

in noncoding regions of DNA

Question 17

Insertions can result in

Answer 17

repeating base sequences of 3 nucleotides expanding tri nucleotide repeat sequences

tri nucleotide repeat disorders

caused due to an abnormal number of triplet repeat sequences

Question 18

Huntingtons Disease - HTT

Answer 18

caused by an abnormality in HTT gene

Mutated dominant allele

Question 19

Deletion example

Answer 19

delta 32 mutation of CCR5 gene

Question 20

what does deletion prevent

Answer 20

functional expression of CCR5 protein co-receptor normally used by HIV -1 to enter CDU + T-cells

HIV can no longer bind to this co-receptor and so cannot efficiently enter checks

Question 21

Mutagenic agents

Answer 21

environmental factors that increase the mutation rate of cells

Question 22

Radiation

Answer 22

can cause chemical changes in DNA, this includes:
High-energy radiation such as UV light
Ionising radiation such as X-rays, gamma rays and alpha particles

Question 23

Chemical substances effect and example

Answer 23

can cause changes to DNA, examples include
nitrosamines found in tobacco smoke
Mustard gas used as a chemical weapon in World War I

Question 24

ionising radiation examples

Answer 24

gamma rays, x rays, alpha particles

Question 25

non-ionising radiation examples

Answer 25

UV radiation

Question 26

random mutation

Answer 26

more likely to occur at certain times in cell cycle such as during DNA replication

can occur anywhere in base sequences of a genome

Question 27

Transition substitution mutation

Answer 27

swaps between bases of similar shape

between 2 ringed purines and 2 ringed pyridines

Question 28

Transversions substitution mutation

Answer 28

Swaps between a purine and pyramidine base

Question 29

why are Transition substitution mutation more common

Answer 29

they keep same ring shape and structure

less likely to occur in amino acid substitutions

Question 30

what is the most common mutation

Answer 30

sequence CG because both involve 3 hydrogen bonds to pair with the base on the opposite strand

Question 31

when happens if there is a mutation in germ cells

Answer 31

if a mutation occurs in a germ cell it can be passed on to the offspring and next generation

Question 32

what are germ lines

Answer 32

Cells involved in inheritance of genetic information, eggs, sperm and zygote

Question 33

what could A mutation that occurs in sperm cells do

Answer 33

potentially affect the zygote of that offspring and all cells developed from that zygote will contain the mutation

Question 34

somatic cell

Answer 34

any biological cell forming the body of a multicellular organism other than a gamete

Question 35

what does cancer arise due to

Answer 35

Cancers demonstrate how important it is that cell division is precisely controlled, as cancers arise due to uncontrolled mitosis

Question 36

are mutations harmful

Answer 36

most mutations are either harmful or neutral

Question 37

use of mutation

Answer 37

without mutation genetic variation would decline over time

used for genetic variation so species can evolve