BIO206H5 Lecture Notes - Lecture 7: Critical Role, Rna, Sigma Factor

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4 Dec 2015

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Oct 1, 2013 transcription: how organism access the info that is coded on dna the several processes together are called gene expression-involves transcription and translation. Transcription initiation site : the boundary between the promoter and 5" utr. The product of transcription is a single stranded mrna that can enter directly into the translation process-no further processing is needed. One thing that is difficult to keep track of is whether a structure belongs to transcription and translation. Biosynthesis begins at 5" end and proceeds to 3"end: one nucleotide at a time: means rna polymerase must be pretty fast. The template strand is being read in the antiparallel from 3" to 5" end, the synthesis occurs from 5" to 3" end. Atp is the identical molecule that is involved in energy metabolism so it plays more than one critical role. The dna template needs to bind to rna polymerase before catalysis can occur.

Related Questions

5. Alpha amanitin is a drug that binds RNA polymerase andprevents it from functioning in the cell (this is the compound thatis found in poison mushrooms). The reason people die when theyconsume alpha amanitin is:

a) Alpha amanitin prevents gene expression from occurring in thecell

b) DNA replication is directly inhibited by alpha amantin

c) Alpha amanitin binds tightly to the messenger RNAs that aremade in the cell, preventing translation

d) Alpha amanitin binds to nuclear pores preventing thetransport of messenger RNA into the cytoplasm

6. In order for transcriptional initiation to begin in E. colithe following elements are needed:

a) an origin and RNA polymerase

b) initiator protein and a promoter

c) the sigma subunit of RNA polymerase and an RNA template

d) RNA polymerase and a promoter

e) helicase and primase

Questions 7 and 8. You are studying two species of closelyrelated snakes, one species lives in sandy desert area and has paletan skin and the species lives in a volcanic rock area and has darkbrown skin. You a sequence the DNA from each type of snake anddiscover a gene encoding a protein that transports pigment into theskin cells. The pigment transporter protein is responsible for skincolor. When you analyze the DNA coding sequence of the pigmenttransporter from each snake you find these two DNA sequences (hashmarks have been added to indicate the reading frame):

pale tan snake: GCG/TTG/GAC/TGC/ACC (DNA template strand)CGC/AAC/CTG/ACG/TGG (complementary strand) dark brown snake:ACG/TTG/GAC/TGC/ACC (DNA template strand) TGC/AAC/CTG/ACG/TGG(complementary strand)

7. From these sequences you conclude:

a) that the amino acid sequence of the pigment transporters forthe two proteins are almost identical

b) that the amino acid sequence of the pigment transporters forthe two proteins are very dissimilar

c) that the amino acid sequence of the pigment transporters forthe two proteins are identical

8. Since the skin color is different in each snake, you concludefrom the sequence data above that:

a) the genetic code in the skin cells in each of these snakes isdifferent

b) the DNA sequence encoding the entire gene for pigmenttransporters in these two snakes is different

c) that one of the codons in the gene for the pigmenttransporter in these two snakes is different

9. You are analyzing eukaryotic cells that have been exposed tothe radioactive uracil. In most cells the radioactive uracil isinitially localized in the nucleus and then moves from the nucleusto the cytoplasm. However, you observe that in some cells theradioactive molecules stay in the nucleus and never arrive in thecytoplasm. This is most likely a defect in:

a) the transcription of the DNA

b) the processing of the mRNA

c) the translation of the RNA

d) the labeling of the RNA

e) the replication of the DNA

10. Which of the following is true of both eukaryotic andbacterial transcription? (select all that are true)
a) Transcription factors must bind the promoter before RNApolymerase initiates transcription

b) Messenger RNAs must be spliced before translation begins inorder to produce the appropriate gene product

c) During transcription only one DNA strand is used as atemplate to make the messenger RNA

d) Termination of transcription occurs when the RNA polymerasetranscribes a hairpin structure in the RNA followed by a string ofU

erinporpoise384

1. The Pribnow Box is a

A. attenuator

B. enhancer

C. promoter

D. operator

2. Which of the following do not occur during post-transcriptional processing of RNA in eukaryotes?

A. the splicing of introns

B. addition of a poly-A at the 3' end

C. removal of introns

D. addition of a 7-methyl guanosine cap at the 5' end

3. In transcription, RNA polymerase binds at

A. a promoter

B. an operator

C. the oriC locus

D. an enhancer

4. The Central Dogma in genetics describes

A. the pattern of information flow in the cell

B. the pattern of chromosomal inheritance in populations

C. the role of mutations in disease

D. the role of promoters

5. Which of the following sequences of DNA could code for a stem-loop structure (only the template strand is shown)?

A. 3'--G-G-C-C-C-T-T-G-G-A-A-A-A-C-C-A-A-G-G-G-C-C--5'

B. 3'--G-G-C-C-C-T-T-G-G-A-A-A-A-G-G-T-T-C-C-C-G-G--5'

C. 3'--G-G-C-C-C-T-T-G-G-T-T-T-T-G-G-C-C-C-T-T-G-G--5'

D. none of the above

6. Removal of introns from RNA is by

A. primosomes

B. peptidases

C. galactosidases

D. spliceosomes

7. Which of the following represents the units for measuring the rate of sedimentation of a molecule/organelle in a sucrose gradient?

A. molecular weight

B. Svedberg units

C. map units

D. Daltons

8. During transcription, which strand is not read by the RNA polymerase?

A. coding strand

B. noncoding strand

C. template strand

D. terminator strand

9. The function of the rho protein is

A. to help terminate translation

B. to help RNA polymerase bind to the DNA

C. to help RNA polymerase find a promoter

D. to help terminate transcription

10. The unusual bases found in transfer RNAs

A. are added during transcription

B. are normal bases that have been modified after transcription

C. help the tRNAs to bind to DNA

D. ensure that the tRNA stays linear in solution

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

BIO206H5 Lecture Notes - Lecture 7: Critical Role, Rna, Sigma Factor

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