BIOA01H3 Lecture Notes - Lecture 4: Transferase, Covalent Bond, Polysome

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scarlettiger519

23 Sep 2016

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Transcription of proteins is first transcribed as a larger precursor with both 5" and 3" untranslated regions. Cap and polya tail is not related to dna sequence and is just there enzymatically. There is no strand of t that codes for the polya tail it just happens. Exons are the regions that must survive to make the rna. Introns are the regions that must be cut as the mature rna is created. Last step to rna processing is post-transcriptional and is the removing of introns. Done by a collection of ribonucleoproteins (rna containing proteins) Spliceosome: collection of ribonucleoproteins that accomplish the removal of introns. Snrnps are bound to the intron by recognizing its sequence: loops the intron out, bringing the two exons closer together (spliceosome formed) Spliceosome cleaves at its beginning and the intron folds on itself. Spliceosome cleaves the intron at its end and splices together the exons: snrnps and intron is released, and intron is degraded.

Related Questions

Q.1

A gene has two introns and three exons. The length of exons 1, 2 and 3 is 600, 1200 and 300 bp, respectively, which are separated by 400 bp intron-1 and 800 bp intron-2. Suppose, a mixture of the dsDNA completely covering this gene and the processed mRNA it codes for is heated at 95C for 10 minutes, gradually cooled to room temperature and then viewed under electron microscope (EM). Draw the diagram of the DNA-RNA hybrid that you expect to see under the EM and answer the following questions. You should use different color for DNA and RNA strands , and label the regions that represent dsDNA, ssDNA and RNA-DNA hybrid. The diagram must take into account the length of introns and exons.

Q.2

What is the function of SR and silencer proteins that activates and represses splicing, respectively? Name the domains that are found in these proteins and explain their function. Explain how the splicing silencer proteins inhibit the function of the SR proteins.

greyfrog275

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?

burgundyhedgehog579

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

BIOA01H3 Lecture Notes - Lecture 4: Transferase, Covalent Bond, Polysome

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