BISC207 Chapter Notes - Chapter 17: Uracil, Adenine, Pyrimidine

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violetgrasshopper2

3 Feb 2017

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University of Delaware

Department

Biological Sciences

Course

BISC207

Professor

Nauen Jennifer

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Rna polymerase- responsible for synthesizing rna by polymerization reactions. The strand that is read by the enzyme is the template strand. The other strand is called the non-template strand or coding strand. An rna polymerase performs template-directed in the 5" 3" direction. Rna polymerase does not require a primer to begin transcription. Promoters- regions of dna that promote the start of transcription. Elongation- once rna polymerase begins moving along the dna template synthesizing rna, catalyzes the addition of nucleotides to the 3" end of the growing rna at the rate of 50 nucleotides per second. Termination ends transcription, transcription stops when rna polymerase transcribes a dna sequence called a transcription-termination signal. Eukaryotes have 3 major polymerases 1, 2, 3, each one produces only a certain type of rna. Transcription factors assemble at the promoter and rna polymerase follows. Transcription occurs in the nucleus and translation occurs in the ribosomes located in the cytoplasm.

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

1. There are viruses, called bacteriophage, that infectbacterial cells. Following viral entry, the cell begins tosynthesize viral DNA and viral proteins, leading to the productionof mature virus and the death of the bacterial cell. During thecourse of viral infection, transcription of bacterial genes isturned off so that transcription of viral genes predominates. Whichof the following is the most likely explanation for how the virusmanages to shift transcription from bacterial genes to its owngenes?

a. it synthesizes a viral RNA polymerase that recognizes onlyviral promoters

b. it synthesizes a viral DNA polymerase that recognizes onlyviral origins

c. it synthesizes a viral sigma subunit that directs thebacterial RNA polymerase to viral promoters

d. it has special viral ribosomes that only translate viralproteins

2. Unlike bacterial transcripts, eukaryotic RNA transcripts arechemically modified because:

a. Chemical groups help protect the mRNAs from degradation inthe eukaryotic cytoplasm, bacterial mRNAs are not degraded

b. Chemical groups facilitate the transport of eukaryotic RNAsfrom the nucleus to the cytoplasm, bacterial RNAs are synthesizedin the cytoplasm

c. Eukaryotic RNA polymerases cannot transcribe genes unlessthey are chemically modified, bacterial RNA polymerases transcribeunmodified genes

d. Transcripts in eukaryotic cells contain non coding regionsthat must be removed, bacterial transcripts contain only codingsequence

e. b and d

3. Termination of transcription in both E. coli and eukaryoticcells occurs because

a. there is a termination signal in the DNA following the genesequence.

b. there is a hairpin structure followed by a string of U

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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

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BISC207 Chapter Notes - Chapter 17: Uracil, Adenine, Pyrimidine

BISC207 Full Course Notes

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