Practice Exam #2 Flashcards by Mr. Z

RNA polymerase recognizes which of the following DNA regions in transcription

promoter

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in mutant DNA polymerase without 5’–>3’ exonuclease function, what property is expected to have? it will:

likely to keep the RNA primers

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While prokaryotes have a single transcription factor (_), eukaryotes have several TF-II.

sigma only

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All tRNA molecules:

have a cloverleaf shape for their secondary structure.

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What is the most likely result from mutating a 3’-5’ exonuclease activity in the DNA polymerase?

unable to proof reading

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Before replication start with DNA polymerase, a set of molecules (__________) recognize and bind the origin of replication.

initiator proteins

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Telomerase is a unique enzyme in that:

has a template.

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In eukaryotes, what initially binds to the TATA box on the DNA template?

TBP

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A rho-independent transcription terminator includes:

inverted repeats which when transcribed fold into a hairpin
a region in the RNA molecule that causes RNA polymerase to pause

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Glycosylase and apurinic base are usually associated with:

BER

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The _______ is an expensive protein in the sense that spends ATP to rotate around the single strand of DNA template for the lagging strand.

helicase

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The following terms best associate with: Rec and BRCA

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Eukaryotic transcription factors assist the ______ in binding to the _________.

RNA polymerase; promoter

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Which protein is observed exclusively in association with eukaryotic DNA replication?

telomerase

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In eukaryotes, enzyme responsible for transcribing all protein-coding genes is

RNA polymerase II

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____________ bind to enhancers in eukaryotic cells to increase the rate of transcription.

Transcription activators

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Introns within primary eukaryotic transcripts

Vary considerably in size and number among different genes

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What kind of RNA functions in splicing and is associated with the spliceosome?

snRNA

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A cell of the pancreas would specialize in producing insulin, among other functions, while a muscle cell would specialize in the production of the protein myosin. This means that

Pancreas cells activate the gene that would produce insulin, while muscle cells activate the gene that would produce myosin.

Which enzyme seals nicks and joins Okazaki fragments?

DNA ligase

Is the XP patients, the patients lacking a DNA repair mechanisms are likely to have more or fewer variations between individuals than a species that possesses repair mechanisms?

More, because more spontaneous mutations will go uncorrected.

true or false: Alternative splicing increases variability

true

RNA in eukaryotes is produced in the

nucleus

Which nuclease cuts in the middle of the DNA strand?

endonuclease

All DNA polymerases require a primer with a 3' OH group to begin DNA synthesis. The primer is:

a short stretch of RNA nucleotides.

true or false: The production of polycistronic mRNA in prokaryotes serve as a mechanism of gene regulation because polycistronic mRNA contains the coding sequences for several proteins on a single transcript. These proteins are often the enzymes needed for a common metabolic pathway. This is an economical way for the cell to regulate the synthesis of related proteins in a coordinate manner by a single signal so that appropriate quantities of each are made at the same time. This is termed coordinate regulation.

true

In prokaryotes, the strength of the binding of RNA polymerase to different promoters

Depends on the promoter sequences

true or false: RNA forms a helix.

false

In rho-dependent transcription termination, the rho factor binds to ___________.

mRNA

Which of the following features is common to both DNA replication and transcription?

A sugar-phosphate bond is formed between the 3' hydroxyl and the 5' phosphate

Which of the following is unique to eukaryotes?

removal of introns

When RNA is transcribed from a gene, which strand of DNA is used?

the template strand

If the dispersive model of DNA replication had been correct, Meselson and Stahl would have observed that DNA extracted from bacterial cells following a second round of DNA replication in 14N would have been:

only of hybrid density, and somewhat lighter than after one round of replication.

Which of the following enzymes is responsible for specifically transcribing tRNA in eukaryotic cells?

RNA polymerase III

true or false: The core promoter includes elements such as the TATA box which are usually located downstream from the transcription initiation site. Several transcription factors are required to start initiation in eukaryotes to bind and recognize the promoter region (TBP, BRE and DPE).

false

Which of the following is unique to prokaryotes?

Coupled transcription-translation

DNA replication in eukaryotes differs from replication in prokaryotes in that:

eukaryotic chromosomes have many separate origins of replication, whereas prokaryotic chromosomes have a single origin of replication

true or false: You analyzed two new mutations in the chicken albumin gene. The comparison of the amino acid sequences of the wildtype and mutated proteins showed that one mutation resulted from substitution of Ala in the position 69 by Pro, and in the second mutant, Asn in the position 70 has been replaced by Ser. However, when you cloned and sequenced mutated genes you found that altered codons were not adjacent, in fact they were 318 base pairs apart. An explanation to these findings is that the first mutation has changed the last codon of one exon, while the second mutation has changed the first codon of the next exon. 318 base pairs represent the intron separating two exons.

true

true or false: Every division, lagging strand gets shorter by ~150 nucleotides and there is a minimum length of DNA needed for initiation of an Okazaki fragment. The enzyme telomerase is able to base pair with the last telomeric repeat of the imperfectly replicated DNA strand driving the addition of a hexanucleotide repeat. Telomerase is a DNA polymerase that carries its own RNA molecule to use as a primer at the end of the lagging strand.

true

Single strand binding proteins are usually associated with only one strands of DNA:

lagging

The following terms best associate with: replication error and 3'>5' exonuclease activity

proofreading

In replication, the termitation of the prokaryotes involves a ____________ while eukaryotes involves a ______________.

harpin, cleavage

The simbol (-) on a DNA nucelotide refers to the ____________ direction from the origin of replication.

upstream

Okazaki fragments are associated with synthesis of:

lagging strand

Which mRNA processing event adds stability to the mRNA?

- addition of a 5' cap | - addition of a poly(a) tail to the 3' end

If the DNA molecule below is transcribed from left to right, what is mRNA sequence 5'-TCGACTTGCAGGACCCTGCGGTAC-3' 3'-AGCTGAACGTCCTGGGACGCCATG-5'

5'-UCGACUUGCACCACCCUGCGGUAC-3'.

You have generated a mouse strain in which the mice cannot make functional telomerase. You predict that the mutant mice will:

undergo progressive chromosome shortening each generation.