Transcription

Question 1

Why does DNA go through RNA?

Answer 1

Proliferates as a larger quantity than DNA

Question 2

Transcription Description

Answer 2

DNA -> RNA

Question 3

Enzyme that carries out transcription

Answer 3

RNA Polymerase (DNA-dependent, RNA-synthesizing)

Question 4

Steps of Transcription

Answer 4

1) Promoter Recognition
2) Initiation (Unwind DNA)
3) Elongation (Move down DNA)
4) Termination

Question 5

E.coli RNA Polymerase # of subunits

Answer 5

6

Question 6

How many RNA polymerases do E.Coli have?

Answer 6

1

Question 7

Holoenzyme

Answer 7

All subunits together of RNA Polymerase in E.Coli

2x alpha, Beta, Beta Prime, omega, sigma

Question 8

Core Enzyme

Answer 8

Non-sigma part of holoenzyme

Question 9

2 “hot spots” of E.Coli Promoters

Answer 9

-10 Sequence
-35 Sequence

CONSERVED AND CONSENSUS

Question 10

Promoter Region

Answer 10

Sequence of nucleotides that signal the RNA Polymerase to start transcription

Question 11

Conserved Sequence

Answer 11

Similar throughout Genomes

Question 12

Consensus Sequence

Answer 12

Most likely nucleotides for a given sequence

Question 13

-10 Sequence

Answer 13

TATAAT

Question 14

-35 Sequence

Answer 14

TTGACA

Question 15

Purpose of sigma subunit of holoenzyme

Answer 15

Scans DNA looking for promoter regions, detaches after initiation/elongation starts

Question 16

Types of Transcription Termination in E.Coli

Answer 16

-Rho-dependent
-Rho-independent

Question 17

Purpose of Rho in E.Coli

Answer 17

Identifies RUT sequence (Rho recognition site) in RNA, uses ATP to dislocate RNA from DNA

Question 18

How to terminate w/out Rho (Intrinsic Termination)

Answer 18

RNA contains a sequence that is GC-rich surrounded by self-complementary bases that create a hairpin loop -> detaches

Question 19

Messenger RNA (mRNA)

Answer 19

Nonfunctional RNAs that carry the instructions for making specific proteins (Translation)

Question 20

Ribosomal RNA (rRNA)

Answer 20

Form complexes with ribosomal proteins to make RIBOSOMES for protein synthesis

Question 21

Transfer RNA (tRNA)

Answer 21

Carry singular amino acids (“charged”) to ribosomes for incorporation during protein synthesis

Question 22

RNA Polymerase I

Answer 22

Only in Eukaryotes, transcribes rRNA

Question 23

RNA Polymerase II

Answer 23

Only in Eukaryotes, transcribes mRNA

Question 24

RNA Polymerase III

Answer 24

Only in Eukaryotes, transcribes tRNA, some rRNA

Question 25

Transcription Factors

Answer 25

Accessory (Regulatory) proteins that begin formation of transcription initiation complex, allows RNA poly to bind to promoter sequence ONLY FOR EUKARYOTES

Question 26

Noncoding DNA

Answer 26

DNA that does NOT code for mRNA or other RNAs

Question 27

Spacer DNA

Answer 27

Noncoding DNA between genes

Question 28

Introns

Answer 28

Noncoding DNA within a gene (Not usually found in prokaryotes), removed in RNA processing if needed

Question 29

Exons

Answer 29

Coding Regions within a gene

Question 30

RNA Processing

Answer 30

Post-transcriptionally, but usually concurrently that must be completed prior to export of mRNA -> Intron removal + Exon splicing

Question 31

Machinery of RNA Processing

Answer 31

small nuclear RNA molecules and proteins (snRNPs)

Question 32

snRNP Recognition Sites

Answer 32

"Splice" sites at 5' and 3' ends of introns

Question 33

Spliceosome

Answer 33

Looped intron caused by Adenine near 3' end binding to snRNP and meeting up with snRNP bound 5' splice site brought together by other snRNPs

Question 34

(Excised) Lariat Structure

Answer 34

Self-connected loop of Intron RNA that is brought about when the 5'/3' splice sites are cleaved away (after which the exons are joined and the introns degraded)

Question 35

Eukaryote vs Prokaryote relationship between genome size and complexity

Answer 35

Nonexistent vs Linear

Question 36

Alternative Splicing

Answer 36

Selective use of exons to create multiple proteins from a single pre-mRNA

Question 37

How is the 5' end of eukaryotic mRNA's different from the middle portion of the mRNA?

Answer 37

Still has all 3 Phosphate groups, modified for additional processing

Question 38

RNA 5'-triphosphatase

Answer 38

Cuts off one phosphate from 5' end of mRNA

Question 39

Guanylyl Transferase

Answer 39

Hydrolyzes GTP to GMP in order to attach to 2 phosphates after RNA 5'-triphosphation

Question 40

Methyltransferase

Answer 40

Attaches a methyl group to GMP

Question 41

5' Cap of Eukaryotic mRNA

Answer 41

Methyl - Guanylyl - 3 Phosphates Cap (7-methylguanosine cap)

Question 42

Poly(A) Tail

Answer 42

Long sequence of Adenines added by poly-A Polymerase to the 3' end of mRNA

Question 43

Purpose of 5' cap

Answer 43

1) Recognition of "start signal" for translation 2) Protection from RNA nucleases

Question 44

Purpose of poly-A tail

Answer 44

1) Buffer region for protection against RNA nucleases 2) Increases efficiency of copying of protein

Question 45

Location of Transcription

Answer 45

Nucleus

Question 46

Location of RNA Processing

Answer 46

Nucleus