Exam 3

Question 1

what kind of cells cannot pass down mutations?

Answer 1

somatic cells

Question 2

first disease phenotype correlated with genotype

Answer 2

alkaptonuria

Question 3

phenylketonuria

Answer 3

buildup of phenylpyruvic acid in brain causing permanent affects

Question 4

albinism

Answer 4

inability to produce melanin in skin (recessive)

Question 5

one gene makes one enzyme

Answer 5

beadle and tatum

Question 6

one gene makes one enzyme changed to

Answer 6

one gene makes one polypeptide

Question 7

loss of function in protein is

Answer 7

recessive

Question 8

gain of function in protein is

Answer 8

dominant

Question 9

point mutation

Answer 9

substitution of one base for another

Question 10

transition

Answer 10

purine to purine or pyrimidine to pyrimidine

Question 11

transversion

Answer 11

purine to pyrimidine and backwards

Question 12

transition letters

Answer 12

A -> G or T -> C

Question 13

transversion letters

Answer 13

A -> C / A -> G
G -> C / G -> T

Question 14

missense (anonymous)

Answer 14

changes amino acid (may change function)

Question 15

nonsense

Answer 15

changes codon to a stop codon

Question 16

silent

Answer 16

codes for same amino acid

Question 17

readthrough

Answer 17

changers stop to something else resulting in longer chain

Question 18

depurination

Answer 18

removes bond at either G or A base
- results in apurinic site

Question 19

deamination of cytosine

Answer 19

results in uracil
- causes GC to AT transition

Question 20

wobble base pairing

Answer 20

mispairing due to flexibility in helix

Question 21

oxidizing agents — DNA

Answer 21

damage

Question 22

causes frameshift mutations

Answer 22

• strand slippage (delete)
• unequal crossing over (both)
• repeat regions (“insert”)

Question 23

fragile X symptom

Answer 23

• repeat CGG on X chromosome
• long face and jaw bones and loose joints

Question 24

x-rays cause chromosome breakage leading to

Answer 24

thymine dimers

Question 25

dimers

Answer 25

distort the helix and inhibit replication

Question 26

xeroderma pigmentosum

Answer 26

repair mechanism is defective - tumors on skin surface

Question 27

transposable genetic elements

Answer 27

jumping genes

Question 28

Activator (AC)

Answer 28

complete transposable element with functional transposase and repeats

Question 29

dissociation (DS)

Answer 29

lacking functional transposase gene (deletion) so it requires the AC transposase to move

Question 30

transposons

Answer 30

- ability to move regulatory sequences affecting the gene expression - mutations in drosophila are due to this

Question 31

Direct repair of mutations

Answer 31

corrects structure of abnormal nucleotide without replacing the nucleotide

Question 32

methyltransferase job in direct repair of mutations

Answer 32

restores correct form to incorrectly methylated guanine base

Question 33

translesion DNA polymerases

Answer 33

can bypass lesions on the DNA during replication - often make errors

Question 34

termination deletion

Answer 34

produces acentric fragment which is lost during cell division

Question 35

interstitial deletion

Answer 35

requires 2 breaks

Question 36

acentric fragments

Answer 36

segments that do not contain a centromere

Question 37

haploinsufficiency

Answer 37

single copy of gene is not enough to allow the wild-type phenotype to occur

Question 38

pseudodominance

Answer 38

expression of normally recessive phenotype because there is no homologous allele due to deletion

Question 39

tandem duplication

Answer 39

direct duplication - AB.CDEFDEFGH

Question 40

reverse tandem

Answer 40

reverse duplication - AB.CDEFFEDGH

Question 41

displaced (homobrachial)

Answer 41

- AB.CDEFGHDEF

Question 42

displaced (heterobrachial)

Answer 42

- DEFAB.CDEFGH

Question 43

paracentric inversion

Answer 43

does not include centromere - ABCDE.FGH - ADCBE.FGH

Question 44

pericentric inversion

Answer 44

includes centromere - ABCDE.FGH - ABCF.EDGH

Question 45

inversions lead to speciation because

Answer 45

cross over products in heterozygotes are not viable while in homozygotes they are

Question 46

reciprocal translocations

Answer 46

2 nonhomologous chromosomes exchange arms

Question 47

non-reciprocal translocation

Answer 47

a segment from one chromosome is moved to a nonhomologous chromosome - AB.CDEFG JK.LM - AB.CFG JK.LDEM

Question 48

robertsonian translocation

Answer 48

2 telocentric chromosomes combine to make one large one - small amount of DNA lost

Question 49

familial down syndrome due to

Answer 49

robertsonian translocation or isochromosome

Question 50

isochromosome

Answer 50

2 chromosome 21s join together

Question 51

which repair mechanisms involve the removal of a single nucleotide

Answer 51

proofreading and base excision repair

Question 52

wildtype

Answer 52

will grow on minimal media since it is capable of synthesizing arginine

Question 53

mutant

Answer 53

requires supplemental arginine for growth

Question 54

Which repair mechanisms involve the removal of several nucleotides?

Answer 54

nucleotide excision repair and mismatch repair