Mutations 2

Question 2

What is evolution?

Answer 2

The change in characteristics of a species over time

Question 3

What definition of genotype?

Answer 3

The genetic make up of an organism

Question 4

what definition of phenotypes ?

Answer 4

The observed traits

Question 5

what definition of population?

Answer 5

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

Question 6

what definition of gene pool?

Answer 6

The sum of all the alleles in a given population

Question 7

what definition of allele frequency ?

Answer 7

how common an allele is in a given population

Question 8

what definition of mutation ?

Answer 8

change in the DNA sequence of an organism

Question 9

what definition of gene mutation ?

Answer 9

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

Question 10

what definition of chromosomal mutation ?

Answer 10

All or part of a chromosome is affected

Question 11

what is the cause of a mutation?

Answer 11

Mutagens such as mustard gas, radioactive waste

Question 12

what are the types of mutations?

Answer 12

Induced mutations - mustard gas
Spontaneous mutation - random errors

Question 13

what categories can mutations be separated into?

Answer 13

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

Question 14

what are heritable mutation ?

Answer 14

• 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 15

what is the extent of the mutation?

Answer 15

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

Question 16

what is the effect of mutations?

Answer 16

changes in nucleotide may cause point or frameshift mutation

Question 17

what are point mutation?

Answer 17

• Missense
• Nonsense
• Neutral
• Silent
• Substitution

Question 18

what is a missense mutation?

Answer 18

causes a change in amino acid

Question 19

what is a nonsense mutation?

Answer 19

change in the base sequence to code for a stop codon

Question 20

what is a neutral mutation?

Answer 20

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

Question 21

what is a silent mutation?

Answer 21

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

Question 22

what is a substitution mutation?

Answer 22

an existing nucleotide is replaced with another one

Question 23

what are frameshift mutation?

Answer 23

-inserted
-deletion

Question 24

what is an insertion mutation?

Answer 24

• a new nucleotide is added

Question 25

what is a deletion mutation?

Answer 25

- a nucleotide is removed from the DNA strand

Question 26

what are chromosomal mutations?

Answer 26

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

Question 27

what are the causes of chromosomal mutations ?

Answer 27

-error in mitosis, meiosis, fertilisation -mutagens

Question 28

what are some examples chromosomal mutations?

Answer 28

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

Question 29

what is duplication ?

Answer 29

a section of chromosome occurs twice

Question 30

what is deletion ?

Answer 30

a section of DNA is removed

Question 31

what is inversion?

Answer 31

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

Question 32

what is translocation?

Answer 32

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

Question 33

what is non-disjunction?

Answer 33

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

Question 34

how is variation caused?

Answer 34

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

Question 35

what is random genetic drift?

Answer 35

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

Question 36

what is the bottleneck effect?

Answer 36

when a population is sharply reduced

Question 37

what is the founder effect?

Answer 37

when a small group moves away from its homeland

Question 38

how is gene flow created?

Answer 38

the movement of alleles from one population to another through migration

Question 39

what do barriers do?

Answer 39

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

Question 40

what are the types of barriers?

Answer 40

- Geographical barriers - Sociocultural barriers

Question 41

what is the population frequency of Tay – Sachs disease?

Answer 41

Jewish decent from Eastern Europe Sociocultural barrier Protection from TB

Question 42

what is the population frequency of Thalassaemia?

Answer 42

Mediterranean coast and South East Asia Sociocultural barrier Protection from malaria

Question 43

what is the population frequency of Sickle – cell anaemia?

Answer 43

Black Africans - Protection from malaria

Question 44

what is the process of natural selection ?

Answer 44

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 45

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

Answer 45

-variation -birth rate -natures balance