Unit 1 - KA6 - Mutations

Question 1

Mutation

Answer 1

Change in the structure or amount of DNA

Question 2

When do mutations occur

Answer 2

Randomly

Spontaneously

Question 3

ROLF

Answer 3

mutations are of Random Occurrence and Low Frequency

Question 4

Single Gene Mutations

Answer 4

Change in one base pair

Question 5

What are single gene mutations also known as?

Answer 5

Point Mutations

Question 6

Deletion

Answer 6

One nucleotide lost

Question 7

Insertion

Answer 7

One nucleotide added to sequence

Question 8

Substitution

Answer 8

One nucleotide removed and replaced with another

Question 9

What does deletion and insertion lead to?

Answer 9

Frame shift Mutation

Question 10

Frame shift Mutation

Answer 10

Code triplets shift forwards/backwards.

All amino acids coded for after the mutation are effected.

Question 11

What 4 things can substitution result in?

Answer 11

• Silent Mutation
• Neutral Mutation
• Missense Mutation
• Nonsense Mutation

Question 12

Silent Mutation

Answer 12

New triplet codes for the same amino acid so protein functions normally.

Question 13

Neutral Mutation

Answer 13

New triplet codes for different amino acid however it is similar to the original so mutated protein functions normally.

Question 14

Missense Mutation

Answer 14

Triplet codes for a different amino acid which changed the function of the protein.

Question 15

Nonsense Mutation

Answer 15

Stop codon is created or lost causing the length of polypeptide chain to change, thus creating a non-functioning protein or a different protein.

Question 16

Splice site mutation

Answer 16

Single gene mutation occurs at a splice site leading to one or more introns being left in mature mRNA transcript, thus creating a protein which does not function properly.

Question 17

Chromosome Mutations

Answer 17

Change in number or sequence of genes on a chromosome.

Question 18

Deletion (chromosome)

Answer 18

Set of genes become detached and are lost completely.

Question 19

Deletion has Big or small Effect?

Answer 19

Big

Question 20

Example of Deletion

Answer 20

Cri du chat syndrome, deletion of part of chromosome number 5.

Question 21

Inversion

Answer 21

Chromosome breaks in 2 places, set of genes become detaches, rotate 180 degrees and attach again so the normal sequence of genes is reversed.

Question 22

Effect of iNVERSION

Answer 22

Non viable gametes because chromosome have difficulty pairing up during gamete formation.

Question 23

Translocation

Answer 23

Genes transfer from one chromosome to another.

Question 24

Effect of translocation

Answer 24

Down syndrome

Question 25

Duplication

Answer 25

Set of genes is repeated on the chromosome.

Question 26

Why is duplication important in evolution?

Answer 26

- single gene mutation in duplicated region of chromosome can produce an advantageous gene without loss of existing gene. - gives organism selective advantage.

Question 27

Polyploidy

Answer 27

Possession of extra sets of chromosomes.

Question 28

What is polyploidy most common in?

Answer 28

Plants

Question 29

£ examples of hybrid vigour in crops

Answer 29

higher yield of fruit greater resistance to disease greater resistance to drought

Question 30

Why do farmers take advantage of polyploidy?

Answer 30

Create bigger or more plants which makes more money.

Question 31

Non-disjunction

Answer 31

Failure of spindle fibers to desperate chromosomes during cell division.

Question 32

Why is polyploidy important in evolution?

Answer 32

- duplication of entire genomes resulted in increased diversity among flowering plants. - extra sets of chromosomes have the ability to mask any conditions caused by recessive alleles.