MBIO 4600 Lecture Notes - Lecture 3: Sigma Factor, Consensus Sequence, Pyrophosphate

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amaranthsardine908

25 Dec 2015

School

University of Manitoba

Department

Microbiology

Course

MBIO 4600

Professor

Brassinga Ann

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Document Summary

Cis-dominant affects expression of genes on the same segment of. 480 kda complex with 2 alpha, 1 beta, 1 beta", and 1 omega subunit core enzyme: auxillary sigma factor + core enzyme holoenzyme. Auxillary sigma factor recognizes the promoter sequence directing polymerase to the start site: in e. coli, there are several sigma factors each recognizing a different type of promoter allows differential regulation of groups and genes. Transcription bubble formation: rna synthesis: base-pairing selection of ntp and linkage to. 3"oh on chain releasing inorganic pyrophosphate (cid:1) (cid:1) (cid:1: release of sigma factor, dna:rna hybrid (8-9 bp long) Pauses and backtracking common during transcription elongation. May aid in correct folding of rna structure. Not restricted to individual genes: operons have only one. Two types of termination sites: rho-independent. Gc-rich inverted repeat followed by a stretch of u"s. U"s causes pausing of rna polymerase allowing hairpin formation of gc-rich inverted repeat region. Characterized by rut site (~40 bp c-rich sequence)

Related Questions

Which type of RNA is unique to eukaryotes?

		mRNA
		rRNA
		tRNA
		snRNA
		Its a trick, all cells have all four types of RNA.

1 points

QUESTION 2

The region of DNA to which RNA polymerase binds to initiate transcription is the:

		origin
		promoter
		enhancer
		none of the above are correct

1 points

QUESTION 3

Holoenzyme:

		is RNA polymerase core enzyme.
		is sigma factor.
		is core plus sigma factor.
		none of the above are correct.

1 points

QUESTION 4

Which of these is formed FIRST when RNA polymerase binds to a promoter?

		The closed promoter complex
		The open promoter complex
		A rho-independent terminator
		none of the above are correct.

1 points

QUESTION 5

A hairpin loop followed by a run of Us:

		is the sequence formed in the sense strand of a gene using a rho-independent terminator.
		is the sequence recognized by the rho protein.
		is the structure formed in RNA that causes rho-independent termination.
		is formed immediately after the open promoter complex is formed.

1 points

QUESTION 6

RNA polymerase:

		reads the template strand of the DNA in the 3' to 5' direction.
		synthesizes the RNA in the 5' to 3' direction.
		can begin transcription without a primer.
		all of the above are correct.

1 points

QUESTION 7

Which of the following statements is FALSE?

		Bacteria like E. coli have only one type of sigma factor.
		RNA polymerase has no proofreading activity.
		The promoter of a gene is upstream of the RNA-coding region.
		Bacterial transcriptional terminators are copied into RNA to cause termination.

1 points

QUESTION 8

If the template strand of a gene has the sequence 5' ATGCGAT 3', then:

		the RNA produced will have the sequence 5' AUGCGAU 3'.
		the RNA produced will have the sequence 5' UAGCGUA 3'.
		the RNA produced will have the sequence 5' AUCGCAU 3'.
		None of the above are correct.

1 points

QUESTION 9

The sense strand:

		is the lagging strand
		is also the template strand.
		always goes left to right.
		none of the above are correct.

1 points

QUESTION 10

Which of these is transcribed but not translated?

		mRNA
		tRNA
		rRNA
		all of the above
		tRNA and rRNA are transcribed but not translated.

please help i am a bit confused

Please help on these. Thank you!

Question 1

Which of the following is NOT a channel in the RNA polymeraseenzyme?

		RNA exit channel
		DNA entry channel
		DNA exit channel
		Nucleotide exit channel

Question 2

A promoter region upstream of a bacterial gene typically has thesequence TTGACA in the -35 position and TATAAT in the -10 position.If there was a 5 bp insertion at the -40 position, such thateverything downstream was shifted (ie: the "-35 element" is now atthe -30 from the transcription start site), which of the followingwill occur?

		Sigma protein will not bind and so no transcription willoccur.
		RNA polymerase will not bind and so no transcription willoccur.
		Sigma protein will bind to its target sequences and sotranscription will start 5bp downstream from the originaltranscription start site.
		Sigma protein will bind as usual and transcription will startappropriately at the transcription start site.

Question 3

A person has a mutation that prevents TFIIH from being produced.Which of the following outcomes will occur?

		No transcription because TFIID will not be able to bind.
		No transcription because the DNA strand will not be opened.
		Transcription will occur, but it will not be in the correctposition.
		Transcription will occur as usual.

Question 4

There are 4 rRNAs produced to make both subunits of theribosome. How many transcripts are required to produce these 4rRNAs?

		1
		2
		3
		4

Question 5

True or False: the 5' 7m-Gppp cap is attached to the start codonof the mRNA.

		True.
		False, the cap is attached to the 5'-untranslated region.
		False - the cap is attached to the 3'-untranslated region.
		False, the cap is attached to the polyA tail.

Question 6

During the splicing mechanism, which of the following joins twoexons together?

		A 2'OH attacks a 5' phosphate
		A 5' phosphate attacks a 2'OH
		A 3'OH attacks a 5' phosphate
		A 5' phosphate attacks a 3'OH Question 7 After their experiment in Neurospora, Beadle and Tatum concludedthat each single genes code for single enzymes. Do you agree withtheir statement, why or why not?

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MBIO 4600 Lecture Notes - Lecture 3: Sigma Factor, Consensus Sequence, Pyrophosphate

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