Ch. 18 Mutation

Question 1

Mutation

Answer 1

an inherited change in genetic information (descendents may be cells or organisms)

Question 2

blank mutations are inherited; blank mutations are not inherited

Answer 2

germ-line; somatic

Question 3

Germ-line tissue gives rise to

Answer 3

gametes

Question 4

If there is a mutation in the 5’ flanking region…

Answer 4

this is a regulatory mutation; may have effects on initiation of transcription, may affect RNA polymerase binding to the promoter, or may affect enhancer regulation of transcription

Question 5

If there is a mutation in the exons that means…

Answer 5

there is a coding mutation; silent, missense, nonsense, or frameshift

Question 6

If introns are mutated

Answer 6

non-coding mutation; most likely has no effect; may affect enhancer regulation of transcription

Question 7

If the intron-exon junction is mutated this is a

Answer 7

splice site mutation; may affect the splicing of the transcript (aka the removal of introns)

Question 8

if there is a mutation in the 3’ flanking region then

Answer 8

this is a regulatory mutation; may affect the termination of transcript; may affect enhancer regulation of transcription

Question 9

Transition

Answer 9

purine to purine
or
pyrimidine to pyrimidine

Question 10

Transversions

Answer 10

purine to pyrimidine (vise versa)

Question 11

expanded nucleotide repeats

Answer 11

large regions of simple repeat sequences present in some genes; can cause repeat expansion due to strand slippage; cause of Huntington’s Disease

Question 12

Anticipation (expanding nucleotide repeats)

Answer 12

the number of repeats tends to correlate with age of onset and severity of disease and tend to worsen with subsequent generations

Question 13

Fragile-X Syndrome

Answer 13

an excessive number of the CGG repeat that causes the loss of function of the FMR-1 gene

Question 14

What are the possible effects of mutations on gene function

Answer 14

neutral, loss of function, gain of function, conditional, and lethal

Question 15

Forward Genetics

Answer 15

start with phenotype to find the mutated gene

Question 16

Reverse Genetics

Answer 16

Start with mutated gene to find the phenotype it causes

Question 17

What causes the occurrence of mutations?

Answer 17

Spontaneous mutations (natural) and Induced mutations (external, chemical)

Question 18

Examples of spontaneous mutations

Answer 18

strand slippage during DNA replication, deamination, unequal crossing over in meiosis I

Question 19

What type of mutation can strand slippage cause?

Answer 19

insertions or deletions- depends on the strand the loop is on

Question 20

What type of mutation does deamination cause?

Answer 20

transition mutation (changes the base) (often changes C to T)

Question 21

What type of mutation does unequal crossing over in meiosis I produce?

Answer 21

insertions and deletions

Question 22

Mutagen

Answer 22

chemicals that can cause mutations in DNA

Question 23

Base analogs

Answer 23

chemicals with structures similar to that of nucleotides; if present the DNA polymerase cannot distingish them and will incorporate in DNA

Question 24

What type of mutation will 5BU (base analog) lead to?

Answer 24

transition (5BU analog of thymine)