8.1 Mutations

Question 1

What is a point/gene mutation?

Answer 1

change in DNA base sequence
changes the amino acid sequence
changes primary structure
changes tertiary structure
changes the function

Question 2

When does a point mutation occur?

Answer 2

during DNA replication in interphase

Question 3

What increases the chance of mutations?

Answer 3

mutagens

Question 4

Why are mutations a good thing?

Answer 4

important for an organism to live through natural selection
the population can evolve

Question 5

What is a chromosome mutation?

Answer 5

a change in the number of chromosomes - extra/less

Question 6

When does a chromosome mutation occur?

Answer 6

during meiosis in anaphase 1 or 2

Question 7

What are all the different types of point mutations?

Answer 7

substitution
insertion
deletion
duplication
inversion
transloaction

Question 8

What is substitution mutation?

Answer 8

only 1 amino acid is changed in the sequence

Question 9

Why does a substitution reaction have little effect?

Answer 9

degenerate code - can code for the same amino acid so its a silent mutation

Question 10

What is insertion mutation?

Answer 10

adding an extra base to the sequence

Question 11

What is a frameshift?

Answer 11

every codon downstream of the mutation will change so potentially every amino acid downstream of the mutation will change

Question 12

What is deletion mutation?

Answer 12

removal of a base

Question 13

What is duplication mutation?

Answer 13

the base that came before is copied and inserted

Question 14

What is inversion mutation?

Answer 14

a group of bases becomes separated from the DNA and rejoin in reverse order

Question 15

What is translocation mutation?

Answer 15

bases are separated from DNA sequence and one chromosome is inserted in a different chromosome

Question 16

What 3 types of mutation cause a frameshift?

Answer 16

insertion
deletion
duplication

Question 17

What are the 2 results from chromosome mutations?

Answer 17

polysomy or polyploidy

Question 18

What does polysomy mean?

Answer 18

occurs when 1 homo pairs fail to separate in the process of non-disjunction = 22 pairs
there is an extra chromosome

Question 19

What does polyploidy mean?

Answer 19

all homo pairs have failed to seperate and end up in the gametes so there is more than 2 sets of chromosomes

Question 20

What does non-disjunction result in?

Answer 20

the gamete has one more or one less chromosome

Question 21

When does a whole change in a set of chromosomes occur?

Answer 21

when an organism has 3 or more sets of chromosomes rather than 2

Question 22

What is hybridisation?

Answer 22

the combining of genes of different varieties or species of organism to produce a hybrid

Question 23

What is triploid?

Answer 23

3 sets of chromosomes

Question 24

What causes down-syndrome?

Answer 24

a tripsomy 21 gamete

Question 25

What is monosomy?

Answer 25

1 set of chromosomes

Question 26

When does production of gametes occur in a female?

Answer 26

when a featusn and continues each month

Question 27

What type of female gamete is most likely to experience non-disjunction?

Answer 27

older gametes

Question 28

What are mutagens?

Answer 28

any outside factor that increases the rate of mutation

Question 29

What are carcinogens?

Answer 29

mutagens that cause cancer

Question 30

What are examples of physical mutagens?

Answer 30

ionisinf radiation
x-rays
alpha and beta particles

Question 31

How do physical mutagens work?

Answer 31

breaks the polypeptide chain in DNA

Question 32

What are examples of biological mutagens?

Answer 32

viruses
benzopyrene in tobacco smoke

Question 33

How does a virus work as a mutagen?

Answer 33

injects viral material and disrupts DNA bases