BIO 110 Lecture Notes - Lecture 14: Spliceosome, Intron, Stem-Loop

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lilacweasel871

3 Oct 2016

School

University of Rochester

Department

Biology

Course

BIO 110

Professor

Clark

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Document Summary

Transcription - highly expressed genes may produce multiple rna copies at the same time by multiple rna polymerases. Transcription usually occurs from one dna template strand. Different genes can have the template strand on either side of the double helix. Rna synthesis is always from 5" to 3" (new bases are added to the 3" end). Unlike dna synthesis, rna synthesis does not require a primer. Transcription factors - proteins that assist in the recognition of, and regulation of gene expression. General transcription factors - transcription factors that are used to initiate transcription for (most) all genes. Beginning transcription - rna polymerase is helped in finding the promoter region of a gene by sigma factor (a protein) In prokaryotes, rna polymerase recognizes specific sequences at about -10 and. 35 bp relative to the start of a coding region of a gene. Elongation - as rna synthesis proceeds, new rna dissociates from the dna, more.

Related Questions

During transcription in eukaryotes, a type of RNA polymerase called RNA polymerase II moves along the template strand of the DNA in the 3'â5' direction. However, for any given gene, either strand of the double-stranded DNA may function as the template strand. Which of the following initially determines which DNA strand is the template strand, and therefore in which direction RNA polymerase II moves along the DNA?

A. the location of specific proteins (transcription factors) that bind to the DNA

B. the specific sequence of bases along the DNA strands

C. the location along the chromosome where the double-stranded DNA unwinds

D. the position of the geneâs promoter on the chromosome

E. which of the two strands of DNA carries the RNA primer

89) During fasting, glucose is synthesized from gluconeogenesis.Where is glucose used?

During fasting glucose is directed to the brain.

90) Why does DNA polymerase need a RNA primer for replication ofchromosomes?

DNA polymerase cannot start synthesis, only extends on anexisting polynucleotide. RNA polymerase can synthesize without anexisting primer.

91) During replication of chromosomes, synthesis of one strandis continuously extending. Another strand extend discontinuously.Why?

92) Histone proteins are core of nucleosomes. DNA wraps aroundthem. Both DNA and histones are involved in regulation of geneexpression. Transcription factors and enhancers are other elementsof regulation. What would be like if a gene has a promoter but doesnot have tissue specific regulatory protein binding sites?

93) Some of cancer causing genes are involved in DNA repair suchBRCA1 and BRCA2. Why do defects in DNA repair increase chance ofgetting cancer?

copperwhale251

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?