Biochemistry LE 5: Gene Transcription

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What is the base number that serves as the start point for transcription?

+1 (correct)

-5

-1

0

What does the 5′-flanking region of the gene contain?

Exonic sequences

Untranscribed sequences (correct)

Intronic sequences

Coding sequences

What is the name of the primary transcript that contains both intronic and exonic sequences?

pre-mRNA

mRNA

hnRNA (correct)

immature RNA

What is the direction of numbering for nucleotides in the transcribed region of the gene?

From 5′-end to 3′-end Signup and view all the answers

What is the role of the σ factor in gene transcription?

To enable the binding of RNAP to promoter elements Signup and view all the answers

What is added to the 5′-end of the RNA during modification?

Cap site Signup and view all the answers

What is the bacterial counterpart of the TATA box?

Pribnow box Signup and view all the answers

What is the function of exons in the transcribed region?

Regions that carry coding sequences Signup and view all the answers

Where does RNA Polymerase I synthesize rRNA?

Nucleolus Signup and view all the answers

What is the resulting RNA after introns are spliced out?

mRNA Signup and view all the answers

What is the function of the promoter region?

To recognize the start point for transcription Signup and view all the answers

What is the direction referred to as the sequences to the left of the start point?

Upstream Signup and view all the answers

What is added to the 3′-end of the RNA during modification?

Poly(A) tail Signup and view all the answers

What is the role of RNA Polymerase II?

To synthesize mRNA and microRNA Signup and view all the answers

What happens after chain termination and RNAP release?

Another set of RNAP can bind to the DNA template Signup and view all the answers

What happens when there is recognition of promoter elements?

Transcription starts Signup and view all the answers

What is the location of RNA Polymerase III?

Nuclear cytoplasm Signup and view all the answers

What is the product of RNA Polymerase III?

tRNA and other small RNAs Signup and view all the answers

What is the function of RNase P?

To catalyze the cleavage reaction Signup and view all the answers

What is the primary difference between prokaryotic and eukaryotic rRNAs?

Their size and structure Signup and view all the answers

What is the purpose of a transcription termination signal?

To terminate transcription Signup and view all the answers

What is a cistron?

A region of DNA that encodes a single polypeptide chain Signup and view all the answers

What is a characteristic of polycistronic transcripts in bacteria?

They are translated as they are being transcribed Signup and view all the answers

What is the purpose of the 5' methyl cap in eukaryotic mRNA synthesis?

To protect the mRNA from degradation Signup and view all the answers

What is the function of Rho-dependent termination?

To cause the release of the RNA transcript from the template Signup and view all the answers

What is the result of translating a polycistronic transcript?

Multiple proteins are produced Signup and view all the answers

What is a characteristic of eukaryotic mRNA synthesis?

The mRNA has a 5' methyl cap and a 3' poly(A) tail Signup and view all the answers

What is the function of Nef in the assembly of viral particles?

It aids in the assembly of viral particles indirectly Signup and view all the answers

What is the function of Pol?

It is a reverse transcriptase Signup and view all the answers

What is unique about the proofreading activity of reverse transcriptase and RNA polymerase?

They have no proofreading activity Signup and view all the answers

What happens to the viral particle after it binds to the receptor?

It fuses with the cell membrane Signup and view all the answers

What is the result of reverse transcription?

Double-stranded DNA Signup and view all the answers

What is the average number of base pairs in a haploid cell?

3 × 10^9 Signup and view all the answers

What percentage of genes are unique?

64% Signup and view all the answers

Do eukaryotes have operons?

No Signup and view all the answers

How does translation occur in prokaryotes?

Coupled with transcription Signup and view all the answers

What is the result of a viral infection of bacteria?

Parts of the viral DNA are inserted into the CRISPR regions of the bacterial genome Signup and view all the answers

How many chromosomes are present in a haploid eukaryotic cell?

23 Signup and view all the answers

What is the function of the Tat protein in HIV?

It stimulates transcription of the viral DNA Signup and view all the answers

What is the role of the Rev protein in HIV?

It causes the viral RNA transcripts to leave the nucleus unspliced Signup and view all the answers

What is the result of reverse transcription in HIV?

A double-stranded DNA copy is produced Signup and view all the answers

What is the state of the HIV genome after integration into the host cell genome?

It is a provirus Signup and view all the answers

What is the function of the envelope proteins in HIV?

They enter the cell membrane Signup and view all the answers

How are the viral core proteins synthesized in HIV?

They are synthesized as a polyprotein Signup and view all the answers

What is the result of the cleavage of the viral polyprotein in HIV?

The viral particles form and bud from the cell membrane Signup and view all the answers