Transcription Flashcards

1
Q

Describe the primary and secondary structure of RNA

A

primary structure is generally single stranded, but RNA can also form some 3-D secondary structures if it is complementary with itself

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2
Q

What is rRNA?

A

RNA molecule that is a structural component of the ribosome, which is involved in protein synthesis

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3
Q

What is pre-mRNA?

A

immediate products of transcription in eukaryotes that is processed to mRNA; not in bacteria

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4
Q

What is mRNA?

A

messenger RNA; RNA molecule that carries the coding instructions for a polypeptide chain from DNA to a ribosome

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5
Q

What is tRNA?

A

transfer RNA; RNA molecule that carries an amino acid to the ribosome and transfers it to the growing polypeptide chain

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6
Q

What three things does transcription require?

A
  1. A DNA template
  2. raw materials (ribonucleotide triphosphates)
  3. a transcription apparatus (associated proteins and enzymes)
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7
Q

What is the template strand?

A

The DNA nucleotide strand that is used as the template during transcription; the RNA synthesized during transcription is complementary and antiparallel to the template strand

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8
Q

What is the coding strand?

A

The DNA strand that is complementary to the template strand; the RNA transcript will match this strand, except T will be replaced with U

aka the nontemplate strand

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9
Q

What is a transcriptional unit and what are its parts?

A

A sequence of nucleotides in DNA that encodes a single RNA molecule and the sequences necessary for its transcription

Normally contains a promoter, an RNA-coding region, and a terminator

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10
Q

What is the promoter?

A

A DNA sequence that the transcription apparatus recognizes and binds to; indicates the direction of transcription, which DNA strand will be the template, and the starting point of transcription

often upstream of the transcription start site

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11
Q

What is a consensus sequence?

A

A group of common nucleotides (often A and T) in a stretch within the promoter

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12
Q

What is the RNA coding region?

A

The sequence of DNA nucleotides that is copied into an RNA molecule

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13
Q

What is the terminator?

A

sequence of DNA nucleotides that brings about the end of transcription

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14
Q

How do rNTPs differ from dNTPs?

A

rNTPs have a hydroxyl at the 2’ carbon of their sugar (ribose), making it less stable than DNA

RNA nucleotides also utilize U (uracil) instead of T

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15
Q

What is RNA Polymerase and in what direction does it transcribe?

A

The enzyme that synthesized RNA from a DNA template

works from 5’ to 3’

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16
Q

What is a sigma factor?

A

molecule that aids in the binding of RNA polymerase to the promoter and aids in initiation

17
Q

What are rifamycins?

A

a class of antibiotics that prevent RNA polymerase from binding to DNA; does not affect eukaryotic RNA pol

18
Q

What does RNA Pol I synthesize

A

rRNA

19
Q

What does RNA Pol II synthesize

A

pre-mRNA

20
Q

What does RNA Pol III synthesize

A

tRNA

21
Q

Does RNA Polymerase require a primer to begin transcription?

A

no

22
Q

What are the stages of transcription?

A
  1. Initiation
  2. Elongation
  3. Termination
23
Q

What are exons?

A

regions of RNA that code for a protein

24
Q

What are introns?

A

sequences in RNA that do not code for proteins and are spliced out

25
Q

What processing the eukaryotic pre-mRNA undergo?

A
  1. addition of the 5’ cap (modified G)
  2. addition of a poly-A tail to the 3’ end
  3. splicing (removal of introns)