BIOL 2311 Lecture Notes - Lecture 16: Adenine, Polynucleotide, Eukaryotic Transcription

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harlequingiraffe61

26 Jun 2018

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RNA SYNTHESIS:

The nucleotide sequence in the transcribed mRNA is complementary to the base sequence in

DNA

RNA is copied from the template strand which is 3´-to- 5´ in the 5´-to-3´ direction = antiparallel

RNA synthesis does not require a primer and proceeds by the addition of nucleotides to form

mRNA chain

Promoter = nucleotide sequence 5´ to the transcription start site, which is the initial binding

site of RNA polymerase and transcription initiation factors

Promoter recognition by RNA polymerase is a prerequisite for transcription initiation

Many promoters contain a similar DNA sequence = TATAAT = “TATA” box (-10) is a consensus

sequence of many promoters

Consensus promoter sequence at -35 = TTGACA

Transcription termination sites are inverted repeat sequences which can form loops in RNA =

stop signal

Initiation

. Molecular machinery assembles at the promoter and begins synthesizing an RNA copy of the gene

The molecular machinery includes:

Transcription factors (TFs) that bind to the promoter in the area of a special sequence

known as the TATA box

RNA polymerase, an enzyme that catalyzes the assembly of RNA nucleotides into an

RNA strand

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Document Summary

The nucleotide sequence in the transcribed mrna is complementary to the base sequence in. Rna is copied from the template strand which is 3 -to- 5 in the 5 -to-3 direction = antiparallel. Rna synthesis does not require a primer and proceeds by the addition of nucleotides to form mrna chain. Promoter = nucleotide sequence 5 to the transcription start site, which is the initial binding site of rna polymerase and transcription initiation factors. Promoter recognition by rna polymerase is a prerequisite for transcription initiation. Many promoters contain a similar dna sequence = tataat = tata box (-10) is a consensus sequence of many promoters. Consensus promoter sequence at -35 = ttgaca. Transcription termination sites are inverted repeat sequences which can form loops in rna = stop signal. Molecular machinery assembles at the promoter and begins synthesizing an rna copy of the gene.

Related Questions

1 DNA sequences found in introns provide [A] amino acid sequence information.

[B] regulatory information.
[C] no known useful information.

[D] structure for the gene.
[E] alternative DNA splicing possibilities.

3. The TATA box is a(n)
[A] sequence close to the promoter region of many genes.
[B] square-shaped sequence.
[C] enhancer consensus sequence.
[D] activator sequence necessary for proper translation.
[E] None of the above

5. Regarding genes and gene expression, which of the following is not a difference between prokaryotes and eukaryotes
[A] Eukaryotic DNA does not contain a TATA box close to the initiation site as does prokaryotic DNA.

[B] In eukaryotes, RNA polymerase requires

'transcription factors'or initiation.

[C] Prokaryotic genes are often grouped together in

operons.

[D] In eukaryotes, the regulation of several genes at once requires common control elements in each of the genes.
[E] There is a diversity of eukaryotic polymerases that is reflected in the diversity of eukaryotic promoters.

10) In eukaryotic cells, a repressor

[A] is made of DNA.
[B] binds to the enhancer region to block transcription. [

C] is located both upstream and downstream from the promoter.
[D] binds to the operator to block RNA polymerase.

[E] binds to a silencer to reduce transcription rates.

Coordinated regulation of genes in eukaryotic cells [A] is the result of positioning the same regulatory sequence in front of each gene.
[B] results from all of those genes being under the control of one promoter.

[C] occurs because related genes all have the same

operons.
[D] occurs because enhancers cause DNA to bend.

Please provide brief (one sentence) answers:

a) The Mycoplasma chromosome codes for 500 genes, yet it has about 20 promoters. Provide a brief explanation for how this is possible.

b) How many seconds would it take the bacterial RNA polymerase to synthesize an mRNA of 5,000 bases?

c) How many mistakes would the bacterial RNA polymerase make while synthesizing an mRNA of 30,000 bases?

d) Sigma (?) protein by itself does not bind to promoter sites. Predict the effect on transcription of a mutation enabling ? to bind tightly to the â35 region in the absence of other subunits of RNA polymerase.

e) What is the structure of the most common transcription terminator signal in E. coli, and what are 2 conserved features of the RNA sequence of this structure?

f) Why is RNA synthesis not as carefully monitored for errors, as is DNA synthesis?

ivorysea-lion342

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

BIOL 2311 Lecture Notes - Lecture 16: Adenine, Polynucleotide, Eukaryotic Transcription

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