9.1 mutations

Question 1

what is a gene mutation?

Answer 1

change in the base sequence of chromosomes

Question 2

how do gene mutations arise?

Answer 2

spontaneously during DNA replication

Question 3

what can increase the rate of gene mutations?

Answer 3

mutagenic agents

Question 4

what is a chromosome mutation?

Answer 4

changes in the structure or number of whole chromosomes

Question 5

how do chromosome mutations in the number of chromosomes arise?

Answer 5

spontaneously by non- disjunction during meiosis 1

Question 6

what is non- disjunction?

Answer 6

failure of homologous chromosomes to separate

Question 7

what is a base substitution?

Answer 7

type of gene mutation in which a nucleotide is replaced by another nucleotide that has a different base

Question 8

what is a deletion of base?

Answer 8

type of gene mutation which is a nucleotide is lost

Question 9

does a deletion of a base or a substitution of a base have a bigger impact?

Answer 9

deletion

Question 10

what sort of frame shift occurs in a deletion of a base?

Answer 10

frame shift to the left

Question 11

why would substation of a base sometimes have no effect?

Answer 11

degenerate code so same amino acid coded for

Question 12

what are the 2 chromosome mutations?

Answer 12

• changes in whole sets of chromosomes

- changes in the number of individual chromosomes

Question 13

what is the condition called then the organism has 3 or more sets of chromosomes?

Answer 13

polyploidy

Question 14

explain why errors in DNA replication can be far more damaging than errors in transcription

Answer 14

• errors may be inherited and may affect the whole organism
• errors in transcription usually affect only specific cell, are temporary and not inherited
• less damaging