UNIT 2 - mutations

Question 1

what is a genetic mutation?

Answer 1

its a permanent change to the sequence of bases in DNA

Question 2

what is somatic mutation?

Answer 2

mutation occurs in body cells during the life of organisms

Question 3

what is germ-line mutation?

Answer 3

mutation occurs in gametes and are passed onto off spring

Question 4

what are the 3 causes of mutations?

Answer 4

1. replication errors
2. mutagens
3. transposons

Question 5

what are replication errors in mutations?

Answer 5

is very rare, DNA polymerase functions to proofread and repair errors in replication

Question 6

what are mutagens?

Answer 6

environmental factors that cause changes to the DNA sequence

Question 7

what does repair enzymes do?

Answer 7

monitor and repair irregularities

Question 8

what are transposons?

Answer 8

(jumping genes) sequences of DNA able to move within or between chromosomes

Question 9

what happens if a mutation affects the amino acid sequence of a protein?

Answer 9

the structure of the protein almost always affected

Question 10

what are the 2 types of mutations?

Answer 10

frameshift mutation and point (substitution) mutations

Question 11

what happens in a point (substitution) mutation?

Answer 11

there is a change in a single nucleotide

Question 12

what codons are unaffected in a point (substitution) mutation

Answer 12

downstream codons

Question 13

what is nonsense in a point (substitution) mutation?

Answer 13

there is an early stop codon - transcription stops prematurely

Question 14

what is silent in a point (substitution) mutation?

Answer 14

no change to amino acid

Question 15

what is Missense in a point (substitution) mutation?

Answer 15

different amino acid in sequence

Question 16

what is a frameshift mutation?

Answer 16

reading frame is shifted - all downstream codons are affected

Question 17

what is insertion in a frameshift mutation?

Answer 17

one or more nucleotide(s) added to sequence

Question 18

what is deletion in a frameshift mutation?

Answer 18

one or more nucleotide(s) removed from the sequence

Question 19

where do chemical reactions occur?

Answer 19

in the enzymatic “pathway”

Question 20

what happens if a mutation occurs in enzyme 2 causing it to be non-functional?

Answer 20

the pathway can not be completed

Question 21

what is deletion in a chromosomal mutation?

Answer 21

End or segment of chromosome is lost

Question 22

what is duplication in a chromosomal mutation?

Answer 22

segment is repeated

Question 23

what is inversions in a chromosomal mutation?

Answer 23

segment breaks off and is reattached at 180 degrees

Question 24

what is translocation in a chromosomal mutation?

Answer 24

segment moves from one chromosome to another