Genetics Chapter 12

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 along the chromosome where the double-stranded DNA unwinds B) the location of specific proteins (transcription factors) that bind to the DNA C) which of the two strands of DNA carries the RNA primer D) the position of the gene's promoter on the chromosome E) the specific sequence of bases along the DNA strands

Where are magnesium ions found in RNA polymerase holoenzyme?

Which of the following lists steps of mRNA production in eukaryotes in the correct order? A) 5' cap addition, addition of poly-A tail, exon splicing, passage through nuclear membrane, transcription B) Transcription, 5' cap addition, addition of poly-A tail, exon splicing, passage through nuclear membrane C) Transcription, 5' cap addition, addition of poly-A tail, passage through nuclear membrane, exon splicing D) Transcription, addition of poly-A tail, 5' cap addition, exon splicing, passage through nuclear membrane

Which of the following is characteristic of transcription in eukaryotes but not in prokaryotes? A) A single transcript may be transcribed and translated simultaneously. B) A 5' untranslated leader sequence C) A 3' untranslated trailer sequence D) Exon splicing

Which of the following best describes the function of the 5'mRNA cap? A) It provides a site for ribosome binding in the cytoplasm. B) Termination of transcription C) To provide a binding site for poly(A) polymerase

Messenger RNA is usually polycistronic in eukaryotes. A) True B) False

In which cellular organelle do the three posttranscriptional modifications often seen in the maturation of mRNA in eukaryotes occur?

Introns are known to contain termination codons (UAA, UGA, or UAG), yet these codons do not interrupt the coding of a particular protein. Why? A) These triplets cause frameshift mutations, but not termination. B) UAA, UGA, and UAG are initiator codons, not termination codons. C) Introns are removed from mRNA before translation. D) Exons are spliced out of mRNA before translation. E) More than one termination codon is needed to stop translation.

Which of the following is a characteristic of RNA splicing in Eukaryotes? A) It involves removal of introns from a gene sequence followed by transcription and subsequent splicing of exons. B) Exon/intron boundaries are typically characterized by a 5' GU splice junction and a 3' AG splice junction. C) After splicing occurs, the U1, U2, U5, U6 snRNP complex removes remaining exons for degradation. D) It involves recognition of sequence-specific intron/exon boundary sites by cytoplasmic proteins.

A snRNP is best described as _______. A) short mRNA transcripts combined with nuclear protein complexes B) a specific sequence of 7 bases in the mRNA transcript C) small RNAs associated with protein complexes in the nucleus D) the loop structure that forms when two exons are brought into close proximity

Which of the following is most likely attributable to a base substitution at a 5' splice junction? A) Failure of the U2 snRNP to bind the transcript B) An amino acid substitution in the final protein product C) A longer than usual final transcript D) A shorter than usual final transcript

The genetic code is degenerate, meaning that a codon can specify more than one amino acid. A) True B) False

A DNA sequence produces a mutant protein in which several amino acids in the middle of the protein differ from the normal protein. What kind of mutation could have occurred? A) No mutation B) A nonsense mutation C) An addition or deletion mutation D) An addition and a deletion mutation

Which of the following statements about eukaryotic transcription is false? A) Transcription initiation occurs when RNA polymerase binds to a complex of transcription factors at the TATA box. B) The transcripts produced contain both exons and introns. C) Eukaryotic promoter regions contain a TATA box and a CAAT box. D) A polycistronic mRNA may be transcribed if the gene products are used in the same pathway or needed at the same time.

The mRNA formed from the repeating tetranucleotide UUAC incorporates only three amino acids, but the use of UAUC incorporates four amino acids. Why? A) The UAC triplet, produced from the first sequence, does not code any amino acid. B) The first sequence has a "double U" fragment. C) The second sequence is more random. D) The triplets UUA and CUU, produced from the first sequence, code the same amino acid.

In studies using repeating copolymers, AC . . . incorporates threonine and histidine, and CAACAA . . . incorporates glutamine, asparagine, and threonine. What triplet code can definitely be assigned to threonine? A) ACC B) ACA C) CAC D) CAA

What is the initiator triplet in both prokaryotes and eukaryotes? Which amino acid does this triplet recruit? A) UAA; no amino acid called in B) UAA; methionine C) AUG; arginine D) UAA or UGA; arginine E) AUG; methionine

In an overlapping code, what is the maximum number amino acid(s) that would be affected by a point mutation?

In a non-overlapping code, what is the maximum number of amino acid(s) that would be affected by a point mutation?

The genetic code is fairly consistent among all organisms. The term often used to describe such consistency in the code is ________.

mRNA

Unambiguous

Degenerate

nonoverlapping

Jacob and Monod

Frameshift mutations

RNA homopolymers

RNA heteropolymers

anticodon

Khorana

Wobble Hypothesis

Ordered genetic code

GUG

nonsense mutation

Exceptions to the coding dictionary

Overlapping genes

Transcription

RNA polymerase

Holoenzyme

beta and beta prime subunits

sigma factor

promoters

Consensus Sequences

Cis-acting elements

Trans-acting factors

TATA box

Initiation

Chain elongation

Hairpin secondary structure

termination factor p

hnRNA

RNA polymerase II

core-promoter

poly-A tail

self-splicing RNA's

Spliceosome