chapter 18

Question 1

what is mutation

Answer 1

inherited change in the dna sequence

Question 2

who can inherit the mutation

Answer 2

cells or organisms

Question 3

what is the cause of all genetic variation, disease and disorder

Answer 3

mutation

Question 4

what is a somatic mutation

Answer 4

mutation in somatic tissue
does not produce gametes

Question 5

what is germline mutation

Answer 5

mutations in cells that produce gametes, can be passed to future generations

Question 6

what is gene mutation

Answer 6

mutation that affects a single gene

Question 7

how is a gene mutation observed

Answer 7

through phenotypic affects

Question 8

what is a chromosome mutation

Answer 8

mutation that affect the number or structure of chromosomes
Can be observed directly

Question 9

Define base substitution (fig 18.2a)

Answer 9

Alteration of a single nucleotide in the DNA
- thymine can be inserted for a guanine

Question 10

what is a transition base mutation

Answer 10

purine is replaced by a different purine or a pyramidine is replaced by a different pyrimidine

Question 11

what is transversion

Answer 11

purine replaced by pyramidine or vice versa

Question 12

Define insertions and deletions and state what type of mutation these cause

Answer 12

Insertions and deletions: addition or removal of one or more nucleotide pairs
Insertions and deletions can lead to framshift mutations

Question 13

what is a frameshift mutation

Answer 13

changes in the reading frame of the gene,

Question 14

what happens to the amino acids after frameshift mutation

Answer 14

usually alter all amino acids encoded by nucleotides after the mutation

Question 15

what is a frame insertion or deletion

Answer 15

change to a genes reading frame

Question 16

Define expanding nucleotide repeats

Answer 16

Mutations in which the number of copies of a set or nucleotides increases

Question 17

what can expanding nucleotide repeats caus

Answer 17

• ALS

Question 18

Explain how strand slippage can cause the expansion of nucleotide repeats

Answer 18

Misalignment of the sequences or stalling of replication through hairpin formation

Question 19

Explain how expanding nucleotide repeats correspond to anticipation

Answer 19

Diseases caused by expanding nucleotide repeats become more severe in each generation

Question 20

what is anticipation

Answer 20

symptoms of a genetic disorder become more severe

Question 21

what is the diffrence between normal and mutant sequeince

Answer 21

normal: mutant cell dies and is replaced by a normal cell
mutant cell: DNA sequence producers new phenotypes

Question 22

what are the three effect of a base substitution

Answer 22

1. missense mutation
2. nonsense mutation
   3.silent mutation

Question 23

what is a missense mutation

Answer 23

base substitution that results in a different amino acid in the protein

Question 24

what is a nonsense mutation

Answer 24

changes a sense codon( one that specicifes an amino acid) intoa nonsense codon( one that terminates translation)

Question 25

what is a sense codon

Answer 25

specifies an amino acid

Question 26

what is nonsense codon

Answer 26

codon that terminates translation

Question 27

what is a silent mutation

Answer 27

change of the dna within a protein coding portion does not affect the sequence of amino acids that make up the protein

Question 28

what is a codon

Answer 28

sequence of 3 nucleotides that codes for a specific amino acid

Question 29

what is forward mutation

Answer 29

alters the wild tupe phenotype

Question 30

what is reverse mutation

Answer 30

changes a mutant phenotype into wild type

Question 31

what is neutral mutation

Answer 31

-missense mutation changes the amino acid sequence but not the function

Question 32

what is loss of function

Answer 32

cause the complete or partial absence of normal protein. Alters the structure of the protein and it no longer works correctly

Question 33

what is gain of funciton mutation

Answer 33

causes the cell to produce a protein or gene product whose function is not normally present

Question 34

what is conditional mutation

Answer 34

mutations expressed only under certain conditions example: conditional mutations affect the phenotype at elevated temps

Question 35

what is lethal mutation

Answer 35

mutations that cause premature death

Question 36

what is suppressor mutation

Answer 36

genetic change that hides or suprpresses the effect of another mutation

Question 37

where does a suppressor mutation occur

Answer 37

at a site distinct from the site of the original mutation

Question 38

what is intragenic suppressor

Answer 38

take place in the same gene that contains the mutation being suppressed

Question 39

what is intergenic suppressor mutation

Answer 39

occurs in a gene other than the one bearing the original mutation it suppresses

Question 40

what does INTERgenic mutation affect

Answer 40

the way mRNA is translated

Question 41

Differentiate between spontaneous and induced mutations

Question 42

Understand how strand slippage causes insertions/ deletions and nucleotide repeat expansion

Question 43

Understand how unequal crossing causes insertions and deletions

Question 44

Understand how depurinatin can cause base substittions

Question 45

Understand how base analogs can cause mispairings during replication

Question 46

Understand how intercalating agents result in frameshift mutations and know that ethidium bromide is a type of intercalating agent

Question 47

Name 2 types of radiation and briefly explain the types of mutations they cause

Question 48

what can transposons do

Answer 48

they can cause gene mutations and chromosome arragements

Question 49

what are transpososn

Answer 49

jumping genes

Question 50

what is direct repair

Answer 50

altered bases get repaired directly

Question 51

Explain how genetic disease associated with defective repair pathways can increase the incidence of cancer