Lecture 13 (part two of chapter 15) Flashcards

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1
Q

What RNA polymerase transcribes rRNA?

A

Pol I

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2
Q

Eukaryotes have ____ RNA polymerases

A

three

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3
Q

What RNA polmerase transcribes mRNA and some snRNA?

A

pol II

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4
Q

What RNA polymerase transcribes tRNA and some other small RNAs?

A

pol III

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5
Q

Each RNA polymerase recognizes its own _____

A

promoter

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6
Q

RNA Pol I promoters are _____ specific

A

species

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7
Q

RNA Pol II promoters consist of a ____ _______ that can be composed of a number of elements

A

core promoter

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8
Q

T or F: The TATA box is included in the core promoter

A

True

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9
Q

Where RNA Pol III promoters found?

A

within the gene itself

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10
Q

Where is the initiation of transcription at?

A

Pol II promoters

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11
Q

T or F: RNA pol II requires a series of transcription factors

A

True

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12
Q

What are elongation complex factors coordinated by structural features called?

A

carboxyl terminal domain (CTD)

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13
Q

In eukaryotes, the primary transcript must be modified to become ______ mRNA

A

mature

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14
Q

How is the primary transcript modified to become mature mRNA?

A

-addition of 5’ cap
-addition of a 3’ poly-A tail
-removal of introns

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15
Q

Why is the addition of a 5’ cap extremely important?

A

it provides RNA stabiity

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16
Q

What is the process called where GTP is added to 5’ end, with GTP modified by addition of methyl group, called methyl-G cap

A

addition of a 5’ cap

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17
Q

What is the 3’poly-A tail created by?

A

poly-A polymerase

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18
Q

Many eukaryotic genes contain sequences that are ____ represented in mRNA

A

not

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19
Q

What are the non-coding sequences called?

A

introns

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20
Q

What are the sequences that will be translated called?

A

exons

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21
Q

Eukaryotic cells deal with introns by cutting and putting back together the _____ ______ to produce _____ mRNA

A

primary transcript, mature

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22
Q

What is the putting back together the primary transcript to produce mRNA called?

A

pre-mRNA splicing

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23
Q

What particles recognize the intron-exon boundaries?

A

small ribonucleoprotein particles

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24
Q

snRNPs cluster with other proteins to form _______

A

spliceosome

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25
Q

What structure is responsible for removing introns via splicing?

A

spliceosome

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26
Q

T or F: there is no observed rule governing the number of introns per gene, or the size of introns and exons

A

True

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27
Q

What theory explains the presence of introns by suggesting exons are functional domains and intron-exon arrangements represent shuffling of those domains over evolutionary timescale?

A

exon shuffling

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28
Q

What is all the RNAs produced from a genome called?

A

transciptome

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29
Q

What are all the proteins produced from a genome called?

A

proteome

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30
Q

T or F: the ratio of genes o transcripts to proteins is 1:1:1

A

FALSE

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31
Q

What process is of a single primary transcript being spliced into different mRNAs by including different sets of exons being spliced into different mRNAs by including different sets of exons

A

alternative splicing

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32
Q

What process can account for deviation from balanced ratio?

A

alternative splicing

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33
Q

What process can greatly increases the number and variety of proteins encoded in the cell nucleus without increasing the size of the genome?

A

alternative splicing

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34
Q

What is a key macromolecular machine involved in translation that requires interaction with mRNA and tRNA to synthesize proteins

A

Ribosomes

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35
Q

What adds amino acids to the acceptor stem of tRNA?

A

aminoacyl-tRNA

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36
Q

What contains three nucleotides complementary to mRNA codons?

A

anticodon loop

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37
Q

What is the 2d structure of tRNA called?

A

cloverleaf

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38
Q

At what prime is the acceptor end in tRNA?

A

3’

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39
Q

each aminoacyl-tRNA synthetase recognizes only ___ amino acid but ____ tRNAs

A

one, several

40
Q

What type of RNA has an amino added via a charging reaction using the energy from ATP

A

charge tRNA

41
Q

What RNA is an activated intermediate molecule that can undergo peptide bond formation spontaneously

A

charged tRNA

42
Q

Acceptor stem is joined to ______ _______

A

carboxyl terminus

43
Q

What does it mean when the acceptor stem is joined to carboxyl terminus?

A

new peptide bonds are formed between amino group and carboxyl group of linked amino acids

44
Q

T or F: ribosomes do verify amino acid attached to tRNA

A

False

45
Q

What two subunits do ribosomes have?

A

large and small

46
Q

What tRNA-binding site binds the tRNA carrying the next amino acid

A

A (aminoacyl) site

47
Q

What are the three tRNA-binding sites?

A

A,P,E

48
Q

What tRNA binding site binds the tRNA attached to the growing peptide chain?

A

P (peptidyl) site

49
Q

What tRNA-binding sire binds the tRNA that carried the previous amino acid added?

A

E (exit) site

50
Q

What are the two primary functions of ribosomes?

A
  1. decode the mRNA
  2. form peptide bonds
51
Q

What subunit of the ribosome decodes the mRNA

A

primarily small subunit

52
Q

What is the enzymatic component of the ribosome?

A

peptidyl transferase

53
Q

What subunit is peptidyl transferase part of?

A

the large subunit

54
Q

What does the peptidyl transferase do?

A

it forms peptide bonds between amino acids

55
Q

Is the activity of ribosomes mostly thought to be carried out by rRNA or the protein component?

A

rRNA

56
Q

What complex is made up of
1. initiator tRNA charged with N-formylmethionine
2.small ribosomal subunit
3. mRNA strand

A

initiation complex

57
Q

What sequence of mRNA positions the small subunit correctly

A

Ribosome binding sequence (RBS)

58
Q

Once the components in the initiation complex are joined what is added to it?

A

the large subunit

59
Q

What site is the initiator tRNA bound to?

A

The P site

60
Q

What site is typically left empty?

A

the A site

61
Q

How is initiations in eukaryotes different than prokaryotes?

A

1.the initiating amino acid is methionine
2.more complicated initiation complex
3. Lack of an RBS

62
Q

What do eukaryotes have instead of an RBS?

A

small subunit binds to 5’cap of mRNA

63
Q

What phase adds amino acids?

A

elongation

64
Q

the ____ charged tRNA can bind to empty A site

A

2nd

65
Q

In order for elongation to add amino acids it requires a what?

A

an elongation factor

66
Q

What is the elongation factor called that binds to tRNA and GTP?

A

EF-Tu

67
Q

After the 2nd charged tRNA binds to the empty A site what can then form?

A

the peptide bond

68
Q

The addition of successive amino acids occurs as a ____

A

cycle

69
Q

What is the successive amino acid cycle?

A
  1. matching tRNA anitcodon with mRNA codon
  2. peptide bond formation
  3. translocation of ribosomes
70
Q

T or F: in wobble pairing there are more tRNAs than codons

A

FALSE

71
Q

What type of pairing allows for less stringent pairing between the 3’ base of the codon and the 5’ base of the anticodon?

A

wobble pairing

72
Q

T or F: Wobble pairing allows a lower number of tRNAs to accommodate all codons

A

True

73
Q

Elongation continues until the ribosome encounters a ____ codon

A

stop

74
Q

Stop codons do not bind to ______

A

tRNA

75
Q

What factors recognize stop codons?

A

release factors

76
Q

What do release factors do?

A

they release the polypeptide from the ribosome

77
Q

Where in Eukaryotes can translation occur?

A

in the cytoplasm or the rough endoplasmic reticulum (RER)

78
Q

What sequence is at the beginning of the polypeptide sequence bind to the signal recognition particle in the cytoplasm?

A

signal sequence

79
Q

What recognizes the signal sequence and the SRP complex?

A

RER receptor proteins

80
Q

What holds ribosome to RER?

A

docking

81
Q

______ is the beginning of the protein-trafficking pathway

A

protein targeting

82
Q

What is defined as the heritable change in the genetic material?

A

mutations

83
Q

A ______ mutation leads to single-nucleotide variation in populations

A

point

84
Q

What is the substitution of one base for another called?

A

base substitution

85
Q

What are the two categories of base subsitution?

A
  1. transition
  2. transversion
86
Q

What type of base substitution is where a purine- purine or pyrimidine-pyrimidine is mutated?

A

transition

87
Q

What type of base substitution mutation is where a purine-pyrimidine or vice versa is mutated?

A

transversion

88
Q

What are the three classes of point mutations?

A
  1. silent
  2. missense
  3. nonsense
89
Q

What type of class of a point mutation is when the same amino acid is inserted, essentially no net effect?

A

silent mutation

90
Q

What type of class of a point mutation is where it changed the amino acid inserted?

A

missense mutation

91
Q

What type of class of point mutation is where it changed to a stop codon?

A

nonsense

92
Q

The gain or loss of 1 to 50 bp is called an ______

A

insertion/ deletion

93
Q

What characteristics do frameshift mutations have?

A
  1. addition or deletion of a base
  2. much more profound consequences
  3. they alter the reading frame downstream
94
Q

mutations are the starting point for ______

A

evolution

95
Q

Human mutation rates can now be measured directly via _____ ______ of parents and their childern

A

whole-genome sequencing