Chapter Nine: the flow of information from DNA to RNA to Protein

Question 1

pairing of ___ is key to transfer information from DNA to RNA to protein

Answer 1

complementary bases

Question 2

___ of DNA, RNA, and proteins help guide mechanisms of gene expression

Answer 2

polarity (directionality)

Question 3

the flow of genetic information from DNA via RNA to protein

Answer 3

gene expression

Question 4

triplet codons of nucleotides represent individual ___

Answer 4

amino acids

Question 5

a gene’s nucleotide sequence is ___ with the amino acid sequence of the encoded peptide

Answer 5

colinear

Question 6

each nucleotide is part of only ___

Answer 6

one codon

Question 7

studies of ___ showed that codons consist of three nucleotides

Answer 7

frameshift mutations

Question 8

the beginning of a gene establishes a ___ that contains a start and stop codon with multiples of 3 in between

Answer 8

reading frame

Question 9

change grouping of nucleotides as a result of an insertion or deletion

Answer 9

frameshift mutations

Question 10

combinations of ___ mutations restore the reading frame

Answer 10

3+ or 3-

Question 11

template strand of DNA is ___ to mRNA

Answer 11

complementary

Question 12

RNA-like strand of DNA has the same ___ and ___ as mRNA

Answer 12

polarity and sequence

Question 13

5’ to 3’ in the mRNA corresponds to the ___ terminus in the polypeptide

Answer 13

N to C

Question 14

single nucleotide substitutions, conform to the genetic code

Answer 14

missense mutations

Question 15

genetic code is almost ___

Answer 15

universal

Question 16

DNA sequences that provide the signal to RNA polymerase for starting transcription

Answer 16

promoters

Question 17

RNA polymerase adds nucleotides in the ___ direction

Answer 17

5’ - 3’

Question 18

DNA sequences that provide the signal to RNA polymerase for stopping transcription

Answer 18

terminators

Question 19

steps of transcription

Answer 19

1. RNA polymerase binds to promoter sequence
2. sigma factor binds to RNA polymerase to form a holoenzyme
3. region of DNA is unwound to form open promoter complex
4. phosphodiester bonds form between the first two ribonucleotides
5. sigma factor separates from RNA polymerase
6. core RNA polymerase loses affinity for promoter, moves in 3’ to 5’ direction on the template strand of DNA
7. within transcription bubble, NTPs are added to 3’ end of nascent mRNA
8. transcription stops when a termination sequence is reached

Question 20

eukaryotic genes have ___ that are required for efficient transcription

Answer 20

enhancers

Question 21

the single strand RNA that results from transcription

Answer 21

primary transcript

Question 22

in prokaryotes, the primary transcript is ___

Answer 22

the mRNA

Question 23

in eukaryotes, the primary transcript is ___

Answer 23

processed to make mRNA

Question 24

3 post-transcriptional modifications in eukaryotes

Answer 24

1. 5’ methylated cap added
2. 3’ poly-A-tail added
3. introns removed by RNA splicing

Question 25

expressed regions, sequences found in a gene's DNA and mature mRNA

Answer 25

exons

Question 26

intervening regions, sequences found in DNA but not in RNA

Answer 26

introns

Question 27

___ cut out introns

Answer 27

enzymes

Question 28

exons can be ___ after splicing

Answer 28

shuffled

Question 29

three short sequences in the primary transcript that determine where splicing occurs

Answer 29

splice donor branch site splice acceptor

Question 30

two ___ remove an intron

Answer 30

sequential cuts

Question 31

splicing is catalyzed by the ___

Answer 31

spliceosome

Question 32

two bodies that are made up of RNA and protein

Answer 32

ribosomes spliceosomes

Question 33

___ produces different mRNAs from the same primary transcript

Answer 33

alternative splicing

Question 34

carry specific amino acids and match with mRNA code for assembly of a protein

Answer 34

tRNAs

Question 35

each tRNA has an ___ that is complementary to an mRNA ___

Answer 35

anticodon codon

Question 36

a specific tRNA is ___ to a specific amino acid

Answer 36

covalently coupled

Question 37

tRNA that is bound to an amino acid

Answer 37

charged tRNA

Question 38

primary structure of tRNA

Answer 38

nucleotide sequence

Question 39

secondary structure of tRNA

Answer 39

cloverleaf shape, due to base pairing of short complementary sequences within the tRNA

Question 40

tertiary structure of tRNA

Answer 40

L shape, formed by 3-dimensional folding

Question 41

catalyze attachment of tRNAs to specific amino acids

Answer 41

aminoacyl-tRNA synthases

Question 42

flexibility in base pairing between 3' nucleotide in codon and 5' nucleotide in anticodon

Answer 42

wobble

Question 43

the ___ base has wobble ability

Answer 43

third

Question 44

tRNAs have ___ bases

Answer 44

unusual

Question 45

___ are the site of polypeptide synthesis

Answer 45

ribosomes

Question 46

a ribosome has two subunits composed of ___ and ___

Answer 46

RNA and protein

Question 47

ribosomes only assemble when ___

Answer 47

they're needed

Question 48

subunit that binds to mRNA

Answer 48

small subunit

Question 49

subunit that has peptide transferase activity, catalyzes formation of peptide bonds

Answer 49

large subunit

Question 50

in prokaryotes, ribosomes bind to a ___ and an ___

Answer 50

shine-dalgarno box AUG

Question 51

three sequential steps of transcription initiation in prokaryotes

Answer 51

1. small ribosomal subunit binds to mRNA 2. fMet-tRNA positioned in P site 3. large subunit binds

Question 52

steps of translation in prokaryotes

Answer 52

1. small ribosomal subunit binds to 5' cap then migrates to the first AUG codon 2. a charged tRNA brings in Met and binds to the mRNA codon in the P site of the ribosome 3. the large ribosomal subunit binds and begins activity 4. the next charged tRNA brings in the next amino acid corresponding to the nest codon 5. peptide bond is formed between Met and the second amino acid 6. continues until ribosome reaches a stop codon where the polypeptide is released and the ribosomal subunits break apart

Question 53

complex of several ribosomes translating from the same mRNA

Answer 53

polyribosome

Question 54

sometimes ___ or ___ are required to activate the newly translated protein

Answer 54

enzymatic cleavage or addition of chemical constituents

Question 55

the nucleus separates ___ and ___ in eukaryotes

Answer 55

transcription and translation

Question 56

eukaryotic promoters are influenced by ___

Answer 56

enhancers

Question 57

translation ___ differs in prokaryotes and eukaryotes

Answer 57

initiation

Question 58

mutations that do not alter amino acid sequence

Answer 58

silent mutations

Question 59

mutations that replace one amino acid with another

Answer 59

missense mutations

Question 60

missense mutation in which chemical properties of mutant amino acid are similar to the original amino acid

Answer 60

conservative

Question 61

missense mutation in which chemical properties of mutant amino acids are different from the original amino acid

Answer 61

nonconservative

Question 62

mutations that change the codon that encodes an amino acid to a stop codon

Answer 62

nonsense mutations

Question 63

nonsense mutations result in a ___

Answer 63

truncated protein

Question 64

mutations that result from insertion or deletion of nucleotides within the coding region

Answer 64

frameshift mutations

Question 65

loss-of-function mutant alleles are usually ___ to wild-type

Answer 65

recessive

Question 66

mutation that completely blocks function of a gene produce

Answer 66

null (amorphsc) mutations

Question 67

mutation that produces less of wild-type protein, or less effective mutant protein

Answer 67

hypomorphic mutations

Question 68

some loss-of-function alleles can show ___

Answer 68

incomplete dominance

Question 69

some loss-of-function alleles are ___ to wild-type

Answer 69

dominant

Question 70

one wild-type allele does not produce enough gene product to avoid mutant phenotype

Answer 70

haploinsufficiency

Question 71

gain-of-function mutations are usually ___

Answer 71

dominant

Question 72

generate more gene product or the same amount of a more efficient gene produce

Answer 72

hypermorphic mutations

Question 73

generate gene product with new function or that is expressed at an inappropriate time or place

Answer 73

neomorphic mutations

Question 74

example of a neomorphic mutation

Answer 74

ectopic expression of leg-determining gene in structures that normally produce antennae in Drosophila

Question 75

___ alleles prevent the normal protein from functioning

Answer 75

antimorphic (dominant negative)

Question 76

mutations in genes encoding the components of gene expression have ___

Answer 76

global effects