CH. 13 Transcription Flashcards

1
Q

where are RNAs synthesized

A

nucleus

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2
Q

where is mRNA exported to

A

the cytoplasm- where it is translated

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3
Q

What are the building blocks of RNA

A

ribonucleotide triphosphates (NTPs)

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4
Q

When does RNA transcription occur

A

predominantly in G1 and G2 phases

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5
Q

mRNAs are needed for

A

protein synthesis

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6
Q

any DNA sequence that is transcribed into an RNA molecule

A

Gene

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7
Q

The coding strand is the

A

nontemplate strand

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8
Q

Nucleotides are added to the ____ end of the RNA molecule

A

3’ end

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9
Q

In the tree structure of RNA transcription, 3’ (of DNA) is end with the larger or shorter strands of RNA

A

shorter

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10
Q

(RNA christmas trees) The 5’ end of the RNA is closer or farther from the DNA

A

farther

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11
Q

The basal transcription apparatus has

A

general transcription factors, RNA polymerase

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12
Q

RNA poly II consists of 2 sequences called the…

A

regulatory and core sequences

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13
Q

core promoter

A

bound by basal transcription apparatus

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14
Q

is the regulatory promoter upstream or downstream of the core promoter

A

upstream

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15
Q

transcriptional activator proteins

A

affect the rate of transcription

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16
Q

consensus sequences

A

comprise the most commonly encountered nucleotides at each site

17
Q

What happens in transcription initiation

A

the transcription apparatus assembles on the promoter and begin the synthesis of RNA

18
Q

What happens in transcription elongation?

A

TFIIs left on the promoter and RNA polymerase moves along the DNA template

19
Q

What happens in termination

A

Rat1 is a 5’ to 3’ exonuclease that degrades the RNA starting from the 5’ and going to the 3’ until it reaches the transcription machinery once it does this- transcription terminates

20
Q

What are the different parts of mRNA

A

5’ methyl cap, 5’ untranslated region, start codon, protein coding region, stop codon, 3’ untraslated region, poly-A-tail

21
Q

What is the protein-coding region

A

series of nucleotides specificying the amino acids to the added

22
Q

what is the function of of mRNA 5’ UTR

A

necessary for ribosome binding and intron splicing

23
Q

What is the function of the mRNA 3’ UTR

A

regulatory role in mRNA stability and translation

24
Q

why do we need the 5’ methyl cap

A

needed to start translation, increase stability of mRNA, influences intron splicing, added during transcription by an enzyme coupled by Pol II

25
Q

What is the first step in pre-mRNA processing

A

addition of 5’ methyl cap

26
Q

What is the second step in pre-mRNA processing

A

Polyadenylation

27
Q

is the poly-A-tail coded in the DNA

A

no- it is a post-transcriptional modification

28
Q

Why is polyadenylation important

A

increases stability of mRNA, moves mRNA through the cytoplasm, facilitated attachment of the ribosome to the mRNA, is preceded by cleaving of 3’ downstream sequences (pre-mRNAs extend many bases 3’ of the end of the gene)

29
Q

What is the third step in pre-mRNA processing

A

intron splicing: stitch together exons and get rid of introns
(in nucleus, done by the spliceosome)

30
Q

explain the 2 steps of pre-mRNA splicing

A

The pre-mRNA is cut at the 5’ splice site (frees exon 1 from intron and the 5’ end of the intron attached to the branch point forming a lariat); a cut is made at the 3’ splice site and simultaneously the 3’ end of exon 1 becomes covalently bonded to the 5’ end of exon 2

31
Q

Alternative Splicing

A

the same pre-mRNA can be spliced in more than one way to yield different amino acids and therefore different proteins

32
Q

RNA polymerase I

A

large rRNAs

33
Q

RNA poly II

A

mRNA

34
Q

RNA poly III

A

tRNAs

35
Q

Transcriptional Unit

A

a stretch of DNA that encodes an RNA molecule and the sequences necessary for its transcription

36
Q

promoter

A

initial binding site of RNA polymerase; specifies which polymerase is used for the different classes of genes to be transcribed

37
Q

Transcription requires 3 major components

A

a DNA template, raw materials to build a new RNA molecule (NTPS, and the trancription apparatus

38
Q

The basal transcription apparatus is sufficient to initiate…

A

minimal levels of transcription

39
Q
A