Chapter 15: Mutations

Question 1

what is a mutation?

Answer 1

a change in the DNA sequence

Question 2

what are the types of mutations?

Answer 2

point and frameshift

Question 3

what is point mutation?

Answer 3

one nucleotide is changed to a different nucleotide
has the same number of nucleotides

Question 4

what is frameshift mutation?

Answer 4

additional or deletion of at least one nucleotide
change the number of nucleotides

Question 5

what are the types of point mutations?

Answer 5

silent, missense, nonsense

Question 6

what are silent mutations?

Answer 6

the DNA sequence has been changed, but the new codon still codes for the same AA

Question 7

a change in what base may not change the AA?

Answer 7

3rd base

Question 8

what type of mutation?
one nucleotide has been changed to a different nucleotide
new codon codes for the same AA

Answer 8

silent

Question 9

what type of mutation?
one nucleotide has been changed to a different nucleotide
new codon codes for the same AA

Answer 9

silent

Question 10

what are missense mutations?

Answer 10

one nucleotide has been changed to a different nucleotide
new codon codes for a different AA

Question 11

will silent mutations be functional?

Answer 11

yes- same function as before

Question 12

will missense mutation be functional?

Answer 12

maybe, it would make a difference if it is in the active site and regulatory site
not make a huge difference when the AA is similar and it may work as a space holder

Question 13

what is sickle cell anemia caused by?

Answer 13

point mutation in gene for hemoglobin=missense

Question 14

what is nonsense mutation?

Answer 14

one nucleotide has been changed to a different nucleotide
new codon codes for a stop codon
new protein is shortened and missing some of its AA

Question 15

will nonsense mutations be functional?

Answer 15

no, the protein is shortened

Question 16

what type of mutation?
addition or deletion of at least one nucleotide
changes the number of nucleotides

Answer 16

frameshift

Question 17

what are the types of frameshift mutations?

Answer 17

insertion and deletion

Question 18

what is insertion frameshift?

Answer 18

additional of 1 or more nucleotides

Question 19

what is deletion frameshift?

Answer 19

removal of one or more nucleotides

Question 20

will frameshift mutations be functional?

Answer 20

no, many AA are changed because all codons are shifted over

Question 21

where can mutations occur?

Answer 21

germ-line or somatic cells

Question 22

what can mutations be?

Answer 22

harmful: cause changes in protein sequence or gene expression that leads to health problems
nuetral: no effect
beneficial: can have beneficial effect on health

Question 23

mutations are the source of

Answer 23

new alleles

Question 24

what are somatic cells?

Answer 24

body cell (not reproductive)

Question 25

what are germ-line cells?

Answer 25

reproductive cell that makes the sperm or eggs (gametes) testes or ovaries

Question 26

what happens if gametes have mutations?

Answer 26

all cells in embryo will have mutation all cells in organism will have 1 copy of the mutation

Question 27

humans are diploid so 2N = Gametes are haploid so 1N =

Answer 27

2 copies of each chromosome 1 copy of each chromosome

Question 28

how many gametes will have the mutation?

Answer 28

half

Question 29

what happens if somatic cells have mutations?

Answer 29

everytime the cell divides the daughter cells will inherit the mutation/ produce a patch of cells with the mutation

Question 30

what cells mutations will not be inherited and why?

Answer 30

somatic none of the cells that produce the sperm or eggs have the mutation

Question 31

what causes mutations?

Answer 31

spontaneous and induced

Question 32

what are spontaneous mutations caused by? types

Answer 32

caused by mistakes in cellular processes or metabolism errors during DNA replication toxic metabolic products changes in nucleotide structures transposons

Question 33

what is errors during DNA replication

Answer 33

proofreading does not remove all mismatched bases DNA repair enzymes fail to remove all mistakes/ DNA damage

Question 34

what is toxic metabolic products?

Answer 34

metabolism produces relactive chemicals that change structures of bases in DNA

Question 35

when does toxic metabolic products occur?

Answer 35

after the DNA replication is done so the next time it is replicated there is a mistake

Question 36

what is changes in nucleotide structure?

Answer 36

bases can form isomers/ alternate forms = tautomers can cause misprinting during DNA replication

Question 37

what is a tautomer?

Answer 37

alternate form of base

Question 38

each base can change between what two forms?

Answer 38

standard form and tautomer ( alternative form)

Question 39

If the base is in the ___ form during DNA replication the ____ base can be inserted into the DNA = ____ mutation

Answer 39

alternate wrong spontaneous

Question 40

what are transposons?

Answer 40

jumping genes 1000 bases long if a transposing inserts into a gene it will cause a mutation

Question 41

what type of mutation is transposons?

Answer 41

insertion frameshift when the transposon goes into the coding region it will form a really long mRNA and will be nonfunctional

Question 42

what are induced mutations caused by?

Answer 42

environmental agents - chemicals - physical agents: uv light, x-rays

Question 43

what is adenine?

Answer 43

an abnormal base in DNA

Question 44

what is induced mutations?

Answer 44

chemicals change the structure of bases in DNA

Question 45

what does uv light produce?

Answer 45

thymine dimers

Question 46

what is a thymine dimer?

Answer 46

2 thymines on the same strand of DNA form covalent bond

Question 47

during DNA replication thymine dimer is recognized as what is added/produced

Answer 47

1 abnormal base not 2 Ts mismatched base may be added a deletion may be produced

Question 48

what is the process of thymine dimers?

Answer 48

uv light causes thymine dimer crosslinks 2 thymines on same strand of DNA blocks DNA replication

Question 49

thymine dimers cause

Answer 49

mistakes during DNA replication

Question 50

what are the types of DNA repair systems?

Answer 50

mismatch repair nucleotide excision repair (NER)

Question 51

what is mismatch repair?

Answer 51

removes mismatched bases that are present after DNA replication is completed

Question 52

what is nucleotide excision repair?

Answer 52

removes abnormal bases (u, hypoxanthine) and thymine dimers

Question 53

in nucleotide excision repair, the ___ and ___ proteins form a ___ and move along the DNA looking for ____ bases

Answer 53

UvrA and UrvB complex abnormal

Question 54

how does mismatch repair work in relation to nucleotide excision repair?

Answer 54

the same just with different proteins

Question 55

what are the steps for nucleotide excision repair?

Answer 55

1) the UrvA and UrvB proteins form a complex and move along the DNA looking for abnormal bases 2)the UrvA and UrvB bind to region of DNA surrounding the abnormal base=thymine dimer 3) UrvA is released 4) UrvC binds to UrvB and cuts out a region of DNA surrounding the abnormal base= thymine dimer 5) UrvD unwinds DNA and removes cut piece of DNA 6) DNA polymerase 1 fills in gap with DNA 7) DNA ligase connects pieces of DNA together

Question 56

what is xeroderma pigmentioa? symptoms/ results

Answer 56

disease caused by defect in DNA repair enzymes that remove thymine dimers patients blister or freckle when exposed to sunlight develop precancerous lesions skin cancer can’t go out in sun even with sunscreen

Question 57

what is myostatin?

Answer 57

inhibits growth of muscle cells

Question 58

mutation that inactivates myostatin causes

Answer 58

overproduction of muscle cells

Question 59

what is the bully mutation and how is it occurring

Answer 59

myostatin naturally