unit 6 part 2 (6.3-6.7) Flashcards

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1
Q

RNA transcription

A

process that copies a DNA template sequence into a new RNA sequence with RNA polymerase

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2
Q

RNA polymerase

A

enzyme that pries the DNA strands apart and synthesizes a new complementary RNA strand (mRNA)

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3
Q

Initiation (transcription)

A

promoter region has sequences where transcription factors bind, the TF proteins allow polymerase to attach

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4
Q

Elongation (transcription)

A

RNA Polymerase opens up transcription bubble and allows new RNA nucleotides to form hydrogen bonds with the DNA template. RNA polymerase adds bases to 3’ end of growing mRNA transcript///// one or many RNA polymerase can contribute in a convoy onto growing stand

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5
Q

Termination (transcription)

A

mRNA separates from the transcription complex after reaching terminator region

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6
Q

hairpin

A

tertiary structure formed by nucleotides that help separate DNA and RNA

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7
Q

mRNA

A

stores nucleotide sequence that is translated into protein sequences, carries info outside of the nucleus to ribosomes

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8
Q

tRNA

A

translates nucleic acid sequence into sequence of amino acids which are readily available in cytoplasm. anticodon base pairs with complimentary codons in mRNA which signals what amino acid is needed

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9
Q

rRNA

A

forms quartenary structure with other proteins to create functional ribosome, P site holds tRNA carrying the growing polypeptide chain, A site holds the tRNA holding the next amino acid to be added, E site is where the tRNAs leave

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10
Q

introns

A

noncoding sequences within genes

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11
Q

splicing

A

removal of introns from RNA sequence, remaining exons are reassembled to make mature mRNA

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12
Q

GTP

A

modified guanine cap on 5’ end of mature mRNA, stabilizes molecule and blocks any random chemical reactions from taking place in cytosol

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13
Q

Poly-A Tail

A

chain of adenine nucleotides that stablizes 3’ side and protects mRNA and helps ribosomes attach

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14
Q

poly a tail adding mechanism

A

proteins recognize specific sequences within mRNA and recruit poly-a polymerase to complete polyadenilation

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15
Q

alternative splicing

A

extra variation created in mature mRNA depending on which codons are considered introns

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16
Q

splicisome

A

structure made of five small RNA molecules and their proteins joined to a complex, binds to each INTRON and removes it, binds the remaining exons

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17
Q

translation

A

mRNA is read and generated into polypeptides (mRNA –> amino acids)

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18
Q

prokaryotic ribosomes

A

only has cytosolic ribosomes

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19
Q

eukaryotic ribosomes

A

has cytosolic ribosomes and ones bound to the endoplasmic reticulum

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20
Q

translation in prokaryotes occur…

A

while mRNA is being transcribed

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21
Q

initiation (translation)

A

rRNA interacts with the mRNA at the start codon (AUG) at A Site

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22
Q

elongation (translation)

A

amino acids are being added to growing polypeptide at P Sit, tRNA binds to exposed codon and new amino acid attaches to growing polypeptide

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23
Q

termination

A

where process stops (stop codon is read), newly synthesized polypeptide is released, rRNA subunites disassemble

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24
Q

retrovirus translation

A

when a viral RNA invades host cell, the reverse transcriptase copies viral RNA into viral DNA which is integrated into host cell’s genome and then transcribed and translation, resulting in new viruses

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25
Q

common ancestory and translation

A

translation is similar in all organisms, the same nucleotides are used and chemical compatibility

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26
Q

codons

A

nucleotide triplets that code for specific amino acids 5’ to 3’

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27
Q

mRNA editing is only in

A

EUKARYOTES

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28
Q

wobble

A

changing the 3rd base does not always change the amino acid

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29
Q

promoter

A

attachment and initiation point for RNA polymerase, marks the beginning of a gene

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30
Q

transcription unit

A

stretch of DNA that is transcribed into an RNA molecule

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31
Q

transcription factors

A

proteins that mediate binding of RNA polymerase and the initiation of transcription

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32
Q

transcription initiation complex

A

complex of transcription factors and RNA Polymerase bound to promoter

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33
Q

termination (transcription) in prokaryotes

A

in bacteria transcription proceeds through DNA terminator and it is transcribed as the terminator signal causing polymerase to dettach

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34
Q

termination (transcription) in eukaryotes

A

RNA polymerase transcribes a sequence on DNA for poludenylation and the proteins (transcription factors) cut free from polymerase

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35
Q

regulation of gene expression

A

process by which instructions in the DNA are selectively transcribed and translation into functional proteins, accounts for phenotypic differences between organisms

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36
Q

regulatory sequences

A

stretches of DNA that can be used to promote or inhibit protein synthesis based on code

37
Q

regulatory proteins

A

used to assist the promotion or inhibition of protein synthesis, the interactions of regulatory sequences with regulatory proteins controls transcription and determines products

38
Q

epigenetic changes

A

reversible changes in DNA or histones depending on the environmental factors

39
Q

histones

A

proteins used to wrap DNA around, if the packing is tight or loose it can regulate the gene expression

40
Q

tissues

A

groups of cells that have the same function, presence of specific proteins within the tissue’s cells give the tissue it’s function, phenotype depends on gene expression

41
Q

cell differentiation

A

refers to cells within the same organism having different phenotypes (functions)

42
Q

transcription factors

A

proteins that promote or inhibit the transcription of a gene, presence determines how cells differentiate

43
Q

reg proteins vs transcription factors

A

RP: assist promotion/inhibition by interacting with reg. sequence

TF: presence promotes or inhibits transcription

44
Q

phenotype depends on…

A

combination of genes expressed

45
Q

metabolic control of bacteria on two levels

A

1) short term- cells adjust activity of enzymes that are already present through feedback inhibition
2) long term- cells adjust production level of certain enzymes by regulating gene expression at transcription level

46
Q

coordinately controlled

A

PRO ONLY. because all similar functioning genes are clustered together, one “on and off switch” (operator) can control them all

47
Q

operator

A

PRO ONLY. segment of DNA that is the “on and off switch), positioned within the promoter region or between the promoter and enzyme coding gene, controls access of RNA Polymerase.

48
Q

operon

A

PRO ONLY includes operator and promoter and the genes they control, and entire stretch of DNA required for the enzyme production

49
Q

represser

A

PRO ONLY turns off the operon, a protein that binds to the operator and blocks the attachment of RNA polymerase (specific to the operator), usually removed when gene is needed

50
Q

regulatory protein PROKARYOTES

A

produces the repressers, has it’s own promoter and is expressed continuously

51
Q

trp represser

A

allosteric protein

52
Q

corepresser

A

PRO ONLY. small molecule that binds to and activates a represser protein to switch an operon off, reduces the rate of transcription

53
Q

repressible operon

A

PRO ONLY. transcription is USUALLY ON but it can be INHIBITED by a small molecule (corepresser) that binds allosterically to a regulatory protein

54
Q

inducable operon

A

PRO ONLY. transcription is USUALLY OFF bit it can be stimulated with a small molecule (inducer) interacts with a regulatory protein (EX: LAC OPERON)

55
Q

inducer

A

PRO ONLY binds to and inactivates the represser to turn on transcription (ex: allolactase)

56
Q

inducible enzyme

A

PRO ONLY function in catabolic pathways, synthesis is induced by a chemical signal when enzyme is needed to breakdown stuff

57
Q

repressible enzyme

A

PRO ONLY function in anabolic pathways, suspends production of an end product when there’s enough in quantity already

58
Q

activator

A

transcription factors that binds to DNA and stimulates transcription of a gene, the on and off for VOLUME

59
Q

chromatin structure in EUK

A

tightly coiled is less likely to be transcribed, the location of the promoter relative to the nucleosome can affect whether or not it’s transcribed

60
Q

histone acetylation

A

promotes transcription by opening chromatin structure, which allows enzymes to get in and turn genes on

61
Q

DNA methylation

A

condenses DNA, making it impossible for enzymes to enter, turns genes off and can be inherited

62
Q

control elements

A

segments of noncoding DNA having a particular nucleotide sequence that serves as the binding site for transcription factors

63
Q

general transcription factors

A

are essential for transcription of all protein-coding genes (primarily bind proteins), low initiation rate

64
Q

specific transcription factors

A

high level of transcription of particular genes at appropriate time and place, depend on the interactions of control elements and specific transcription factors

65
Q

enhancers

A

distal control elements (genes have many)

66
Q

proximal control elements

A

closer to promoter

67
Q

2 common structural elements of activators

A

1) DNA binding domain
2) one or more activation domains (binds to ref proteins or components of transcription machinery facilitating interactions)

68
Q

negative regulatory molecules

A

INHIBIT gene expression and influences gene products/function

69
Q

RNAi

A

interference RNA, natural protection of cells against viruses that destroys suspicious recipes

70
Q

mutation

A

changes in the genome of an organism, whether it is beneficial, detrimental, or neutral depends on environmental context, primary source of genetic variation

71
Q

neutral mutation

A

change encodes the intended protein

72
Q

positive mutation

A

change encodes a new protein that benefits the cell/organism

73
Q

negative mutation

A

change encodes a new protein that harms the cell/organism

74
Q

triploidy

A

having 3 copies of a particular chromosome, extra chromosome in trisomy 21

75
Q

polyploidy

A

having multiple sets of homologous chromosomes

76
Q

horizontal transfer

A

exchange of genetic info between two different genomes or unrelated organisms

77
Q

transformation

A

IN PRO, uptake of naked DNA (not protected by proteins or other molecules, comes from the external environment)

78
Q

transduction

A

transmission of foreign DNA into a cell, when a viral genome integrates with host genome

79
Q

conjugation

A

IN PRO, cell to cell transfer, external cell extension connects cells and allows transfer

80
Q

transposition

A

movement of DNA segments within or between DNA molecules (inversion, translocation, deletion, duplication)

81
Q

reproductive processes that increase variation

A

sexual reproduction and combination of random gametes, independent assortment of homologous pairs, crossing over during meiosis

82
Q

substitution mutations

A

replacement of one nucleotide and its partner with another pair of nucleotides (usually missense)

83
Q

silent mutation

A

changes that have no observable effect on phenotype

84
Q

missense mutation

A

change in one amino acid to another, might have little effect on protein becuase many have similar properties

85
Q

nonsense mutation

A

a nucleotide changes a codon into a STOP, translation is ended prematurely and leads to nonfunctional protein

86
Q

insertions and deletions

A

additions or losses of nucleotide pairs in a gene, usually have disastorous effects

87
Q

frameshift mutation

A

when a number of nucleotides inserted/deleted is not a multiple of 3, nucleotides become improperly grouped into codons

88
Q

mutagens

A

physical or chemical agents that cause mutations