Mutations

Question 1

What is evolution?

Answer 1

The change in characteristics of a species over time

Question 2

What definition of genotype?

Answer 2

The genetic make up of an organism

Question 3

what definition of phenotypes ?

Answer 3

The observed traits

Question 4

what definition of population?

Answer 4

a group of organisms of the same species living together in a particular place

Question 5

what definition of gene pool?

Answer 5

The sum of all the alleles in a given population

Question 6

what definition of allele frequency ?

Answer 6

how common an allele is in a given population

Question 7

what definition of mutation ?

Answer 7

change in the DNA sequence of an organism

Question 8

what definition of gene mutation ?

Answer 8

change in a single gene so that the trait normally produced by that gene is changed or destroyed

Question 9

what definition of chromosomal mutation ?

Answer 9

All or part of a chromosome is affected

Question 10

what is the cause of a mutation?

Answer 10

Mutagens such as mustard gas, radioactive waste

Question 11

what are the types of mutations?

Answer 11

Induced mutations - mustard gas
Spontaneous mutation - random errors

Question 12

what categories can mutations be separated into?

Answer 12

• induced/spontaneous
• whether they are hereditary
• their effects on proteins
  -extent of mutation

Question 13

what are heritable mutation ?

Answer 13

• Mutation that occur in somatic cell cannot be passed on eg. Cancer
• Germline mutation that occur in gametes can be passed on eg. PKU

Question 14

what is the extent of the mutation?

Answer 14

• The amount of DNA affected
• whether it is a gene or chromosomal mutation

Question 15

what is the effect of mutations?

Answer 15

changes in nucleotide may cause point or frameshift mutation

Question 16

what are point mutation?

Answer 16

• Missense
• Nonsense
• Neutral
• Silent
• Substitution

Question 17

what is a missense mutation?

Answer 17

causes a change in amino acid

Question 18

what is a nonsense mutation?

Answer 18

change in the base sequence to code for a stop codon

Question 19

what is a neutral mutation?

Answer 19

causes a change in the amino acid but the structure of the protein ins’t changed enough to alter function

Question 20

what is a silent mutation?

Answer 20

• do not cause any change in the amino acid or the protein

Question 21

what is a substitution mutation?

Answer 21

an existing nucleotide is replaced with another one

Question 22

what are frameshift mutation?

Answer 22

-inserted
-deletion

Question 23

what is an insertion mutation?

Answer 23

• a new nucleotide is added

Question 24

what is a deletion mutation?

Answer 24

• a nucleotide is removed from the DNA strand

Question 25

what are chromosomal mutations?

Answer 25

- a mutation involving long segments of DNA or chromosome -can increase or decrease number of chromosomes or chromosomes sets

Question 26

what are the causes of chromosomal mutations ?

Answer 26

-error in mitosis, meiosis, fertilisation -mutagens

Question 27

what are some chromosomal mutations?

Answer 27

- Duplication - Deletion - Inversion - Translocation - Non-disjunction

Question 28

what is duplication ?

Answer 28

a section of chromosome occurs twice

Question 29

what is deletion ?

Answer 29

a section of DNA is removed

Question 30

what is inversion?

Answer 30

a break in a chromosome occurs and then is reattached the wrong way

Question 31

what is translocation?

Answer 31

part of a chromosome breaks off and reattaches to the wrong chromosome

Question 32

what is non-disjunction?

Answer 32

occurs during meiosis chromosomes don't seperate properly during anaphase resulting in daughter cells with the incorrect number of chromosome called aneuploidy

Question 33

how is variation caused?

Answer 33

-Random assortment -Crossing over -Non-disjunction -Random fertilisation -Mutation

Question 34

what is random genetic drift?

Answer 34

a non-directional variation in allele frequency that occurs in a small population

Question 35

what is the bottleneck effect?

Answer 35

when a population is sharply reduced

Question 36

what is the founder effect?

Answer 36

when a small group moves away from its homeland

Question 37

how is gene flow created?

Answer 37

the movement of alleles from one population to another through migration

Question 38

what do barriers do?

Answer 38

-prevent inbreeding -creates different selection pressure -development of different gene pools

Question 39

what are the types of barriers?

Answer 39

- Geographical barriers - Sociocultural barriers

Question 40

what is the population frequency of Tay – Sachs disease?

Answer 40

Jewish decent from Eastern Europe Sociocultural barrier Protection from TB

Question 41

what is the population frequency of Thalassaemia?

Answer 41

Mediterranean coast and South East Asia Sociocultural barrier Protection from malaria

Question 42

what is the population frequency of Sickle – cell anaemia?

Answer 42

Black Africans - Protection from malaria

Question 43

what is the process of natural selection ?

Answer 43

1. there is variation within a species 2. there are more offspring produced than can survive to adulthood 3. there is a struggle for existence 4. individuals with favourable characteristics survive and reproduce 5. favourable characteristics are passed on to offspring 6. proportion of favourable alleles gradually increase

Question 44

what is Darwin's theory of natural selection based on?

Answer 44

-variation -birth rate -natures balance