K101 Final Exam Practice Unit 4 Flashcards
(40 cards)
Ch 16 & 17: In e coli, a mutation in a gene called dnaB that alters the helicase enzyme. Which of the following would you expect as a result of this mutation?
A. no proofreading will occur
B. no replication fork will be formed
C. the DNA will supercoil
D. replication will occur via RNA polymerase alone
E. replicato will require a DNA template from another source
F. It is not a ribonucleotide, but a deoxyrubonucleotide
B. no replication fork will be formed
Ch 16 & 17: A double-stranded DNA molecule contains a total of 120 purines and 120 pyrimidines. This DNA molecule could be comprised of, respectively:
A. 120 adenine and 120 uracil molecules
B. 120 thymine and 120 adenine molecules
C. 120 cytosine and 120 thymine molecules
D. 120 adenine and 120 thymine molecules
D. 120 adenine and 120 thymine molecules
Ch 16 & 17: the 5’ end of a DNA strand always has a free _________ group while the 3’ end always has a free _______ group.
A. phosphate; hydroxyl
B. hydroxyl; phosphate
C. phosphate; amine
D. amine; phosphate
E. phosphate; acidic
A. phosphate; hydroxyl
Ch 16 & 17: A mutant bacterial cell has a defective aminoacyl synthetase that attaches a lysine to tRNAs with the anticodon AAA instead of the normal phenylalanine. The consequence of this for the cell will be that:
A. none of the proteins in the cell will contain phenylalanine
B. proteins in the cell will include lysine instead of phenylalanine at amino acid positions specified by the codon UUU
C. the cell will compensate for the defect by attaching phenylalanine to tRNAs with lysine-specifying anticodons
D. the ribosome will skip a codon every time a UUU is encountered
E. none of the options will occur; the ell will recognize the error and destroy the tRNA
B. proteins in the cell will include lysine instead of phenylalanine at amino acid positions specified by the codon UUU
Ch 16 & 17: In the figure to the right, mRNA transcription process initiates at the area labeled ________, the messenger RNA transcription in the figure is labeled _______, and the template strand is labeled _____:
A. EDC
B. EGD
C. ADC
D. ACD
E. AEC
A. EDC
Ch 16 & 17: The most commonly occurring mutation in people with cystic fibrosis is a deletion of a single codon. This results in;
A. a base-pair substitution
B. a nucleotide mismatch
C. a frameshift mutation
D. a polypeptide missing an amino acid
E. a nonsense mutation
D. a polypeptide missing an amino acid
Ch 16 & 17: RNA molecules with enzymatic functions (such as peptidyltransferase) are called ___________.
A. RNA polymerases
B. transfer RNAs
C. polysomes
D. ribozymes
E. aminoacyl-RNA synthetases
D. ribozymes
Ch 16 & 17: according to Beadle and Tatum, how many genes are necessary for the pathway shown below?
A –enzyme A–> B –enzyme B–> C
A. 0
B. 1
C. 2
D. 3
C. 2
Ch 16 & 17: A mutation results in a defective enzyme A. Which of the following would be a consequence of that mutation?
A. an accumulation of A and no production of B and C
B. an accumulation of A and B and no production of C
C. an accumulation of B and no production of A and C
D. an accumulation of B and C and no production of A
E. an accumulation of C and no production of A and B
A. an accumulation of A and no production of B and C
Ch 16 & 17: when translating secretory or membrane proteins, ribosomes are brought to the ER membrane by:
A. a specific characteristic that identifies it as a “bound” ribosome itself
B. a signal-recognition particle that brings ribosomes to a receptor protein in the ER membrane
C. moving through a specialized channel of the nucleus
D. a chemical signal given off by the ER
E. a signal sequence of RNA that precedes the start codon of the message
B. a signal-recognition particle that brings ribosomes to a receptor protein in the ER membrane
Ch 18: In human females, on X chromosome per cell is randomly inactivated during early embryonic development, forming a Barr Body. Much of the DNA in this chromosome is then in the form of
A. introns
B. chromosome puffs
C. heterochromatin
D. euchromatin
E. tetrads
C. heterochromatin
Ch 18: In eukaryotes, histone methylation ______, while histone acetylation ___________
A. marks genes for destruction, promotes transcription
B. promotes transcription, represses transcription
C. imprints genes
D. inactivates genes, reduces the size of the genome
E. represses transcription, promotes transcription
E. represses transcription, promotes transcription
Ch 18: SELECT ALL THAT APPLY: Which of the following are correctly matched with their description?
A. Enhancers (Distal Control Elements) = increase the rate of eukaryotic gene transcription; may be located upstream or downstream from the genes they regulate
B. Promoter TATA box = binding and attachment site for RNA polymerase; located 25-35 base pairs upstream of the transcription start site
C. Proximal control elements = required for accurate transcription initiation; bind numerous transcription initiation complex proteins
A. Enhancers (Distal Control Elements) = increase the rate of eukaryotic gene transcription; may be located upstream or downstream from the genes they regulate
B. Promoter TATA box = binding and attachment site for RNA polymerase; located 25-35 base pairs upstream of the transcription start site
C. Proximal control elements = required for accurate transcription initiation; bind numerous transcription initiation complex proteins
Ch 19: The human crystalline gene is contained in the genome of every cell of a human, but is only expressed (made into protein) in the lens of the eye. This is because:
A. the crystalline gene is spliced out of the genome early in development in all the cells in the body except lens cells
B. activator proteins (transcription factors) that bind to regulatory regions of the crystalline gene are only found in the lens cells
C. the crystalline gene has specific promoter and enhancer control elements that bind to only lens-specific activators
D. all of the above
E. b and c only
B. activator proteins (transcription factors) that bind to regulatory regions of the crystalline gene are only found in the lens cells
Ch 18: which of the following is the attachment site for RNA polymerase?
A. the small subunit of the ribosome
B. the TATAAA box
C. the enhancer
D. the Upstream Promoter Elements
E. the AUG codon
B the TATAAA box
Ch 18: Upstream (proximal) promoter elements in eukaryotes are:
A. nucleotide sequences that act as binding sites for RNA polymerase
B. nucleotide sequences that regulate the efficiency of transcription initiation
C. nucleotide sequences that contain the TATA box
D. proteins that are required for RNA polymerase to bind to the promoter
E. proteins that inhibit RNA polymerase binding to the promoter
B. nucleotide sequences that regulate the efficiency of transcription initiation
Ch 18: Regulation of gene expression can be accomplished by controlling:
A. the amount of chromatin packing
B. the amount of mRNA that is transcribed
C. the rate of translation of mRNA
D. the rate of mRNA degradation
E. all of the above
E. all of the above
Ch 18: Eukaryotic enhancers are capable of which of the following?
A. regulating a gene even if they are cut out of the DNA and reinserted backwards
B. regulating a gene from very long distances
C. interacting with proteins that regulate transcription
D. increasing the rate of RNA synthesis after initiation
E. all of the above
E. all of the above
Ch 18: Which of the following statement about the DNA in one of your brain cells is true?
A. most of the DNA codes for protein
B. the majority of genes are likely to be transcribed
C. each gene lies immediately adjacent to an enhancer
D. many genes are grouped into operon-like clusters
E. it is the same as the DNA in one of your heart cells
E. it is the same as the DNA in one of your heart cells
Ch 18: Gene expression might be altered at the level of post-transcriptional processing in eukaryotes rather than prokaryotes because of which of the following?
A. Eukaryotic mRNAs get 5’ caps and 3’ tails
B. prokaryotic genes are expressed as mRNA, which is more stable in the cell
C. eukaryotic exons may be spliced in alternative patterns
D. prokaryotes use ribosomes of different structure and size
E. eukaryotic coded polypeptides often require cleaving of signal sequences before localization
C. eukaryotic exons may be spliced in alternative patterns
Ch 18: Which of the following is most likely to have a small protein called ubiquitin attached to it?
A. a cyclin that usually acts in G1, now that the cell is in G2
B. a cell surface protein that requires transport from the ER
C. an mRNA that is leaving the nucleus to be translated
D. a regulatory protein that requires sugar residues to be attached
E. an mRNA produced by an egg cell that will be retained until after fertilization
A. a cyclin that usually acts in G1, now that the cell is in G2
Ch 18: MicroRNAs (miRNAs) and small interfering RNAs (siRNAs) both function to “silence” genes, by
A. Causing chromatin de-acetylation and tight winding of the DNA
B. Acting as a release factor to cause ribosome disassembly
C. Activating the Dicer enzyme to rapidly degrade the mRNA
D. Binding to complementary RNA sequences to prevent translation
E. Binding to complementary DNA sequences to prevent transcription
D. Binding to complementary RNA sequences to prevent translation
Ch 18: Alternative RNA splicing:
A. is a mechanism for increasing the rate of transcription.
B. can allow the production of proteins of different sizes from a single mRNA.
C. can allow the production of similar proteins from different RNAs.
D. increases the rate of transcription.
B. can allow the production of proteins of different sizes from a single mRNA.
Ch 18: Which of the following is the first event to take place in translation in eukaryotes?
A. elongation of the polypeptide
B. base pairing of activated methionine-tRNA to AUG of the messenger RNA
C. binding of the larger ribosomal subunit to smaller ribosomal subunits
D. covalent bonding between the first two amino acids
E. the small subunit of the ribosome recognizes and attaches to the 5’ cap of mRNA
E. the small subunit of the ribosome recognizes and attaches to the 5’ cap of mRNA
