BIO 315 Exam 3
If you want to engineer a cytoplasmic protein to become a nuclear protein, which of the following amino acid sequences would you need to add?
A Lys-Lys-Lys-Lys sequence to its N-terminus
Which eukaryotic RNA polymerase is responsible for the synthesis of most rRNAs?
RNA polymerase I
Which eukaryotic RNA polymerase is responsible for the synthesis of most mRNAs?
RNA polymerase II
The DNA from two different species can often be distinguished by a difference in the
Ratio of A+T to G+C
You have a segment of DNA that contains the following sequence and you know the RNA transcribed from this segment contains the following sequence. Which of the following choices best describe how transcription occurs?
The bottom strand is the template strand; RNA polymerase moves along this strand from 3' to 5'
Which of the following eukaryotic pre-initiation complex factors is not correctly paired with its function?
TFIIB: Helps recruit RNA pollI to the complex
Inner membrane mitochondrial proteins use this complex during transport from the cytosol:
TOM complex and TIM22 complex
Which of the following is not true concerning protein processing?
The SER is continuous with the nuclear membrane and the starting point of the biosynthetic pathway
N-linked oligosaccharides on secreted glycoproteins are attached to
The asparagine in the sequence Asn-X-Ser/Thr
To mark proteins that will be degraded through the proteasome, what modification occurs to the protein?
Ubiquitination of lysine residues
In the fusion event between vesicle and target membranes, ____ found in the target membrane interact with _____ found on vesicles to pull the two lipid bilayers together.
tSNAREs; vSNAREs
What DNA sequence is repeated in human telomeres?
5'-TTAGGG-3'
What family of G-proteins determines the specificity of interaction of vesicles with the correct target membrane?
Rabs
Uptake of low-density lipoproteins occurs by ______, whereas retrieval of plasma membrane after extensive secretory activity occurs by _____
Receptor-mediated endocytosis, bulk-phase endocytosis
Which of the following is not true concerning transcription factor motifs?
The HLH motif has two B-pleated sheets separated by a loop
All of the following concerning protein translation are true except:
The Kozak sequence is used in bacteria to locate the correct initiation codon
All of the following concerning bacterial transcription is true except:
Transcriptional termination is always a rho-dependent process
Regulation of ferritin to help detoxify the presence of intracellular iron is an example of:
Translational-level control
Proteins that are fully translated in the cytosol do not end up in
Transport vessicles
Which of the following eukaryotic pre-initiation complex factors recognizes the promoter TATA box?
TFIID
Mitochondrial matrix proteins use this complex during transport from the cytosol
TOM and TIM23 complex
Which enzyme transfers an oligosaccharide to proteins via N-linked glycosylation at the ER?
Oligosaccaryltransferase
Which of the following is not associated with mRNA stability and degradation?
Chaperones
What technique is used to determine DNA binding sites for transcription factors genome-wide?
Chromatin immunoprecipitation
DNA methylation to maintain DNA silencing generally occurs at which base?
Cytosine
The N-terminus of which histone is generally the most extensively modified by chemical modification?
H3
What specific tag added to proteins in the cis-Golgi will route lysosomal enzymes to the lysosome?
Mannose 6-phosphate
After isolating the rough endoplasmic reticulum from the rest of the cytoplasm, you purify the RNAs attached to it. Which of the following proteins do you expect the RNA from the rough endoplasmic reticulum to encode?
(All are correct) 1. Soluble secreted proteins 2. ER membrane proteins 3. Plasma membrane proteins
All of the following concerning the human genome are true except:
(All are true) 1. Gene duplication may arise from unequal crossing over events, and leads to the evolution of multigene families 2. Trinucleotide repeat expansion diseases can occur in introns, coding exons, and untranslated regions (UTRs) 3. The human genome consists of around 20,000 genes 4. The most common type of genetic variability in humans is from single nucleotide differences
In eukaryotes, transposable elements arise by
(All choices are correct) 1. Reverse transcription of RNA, followed by insertion into the genome 2. Excision of a portion of the chromosome, follow by insertion at a new place in the genome 3. Duplication of transposable element's DNA followed by insertion into a new place in the genome
Of the following processes that occur during protein trafficking, which involve GTP?
(All involve GTP) 1. Protein translocation across the RER membrane 2. Disassembly of the COPII coat on a transport vesicle 3. Docking of non-clathrin coated vesicles with their target membrane
With respect to genome structure and stability, all of the following statements are true except:
(All of the above are true) 1. Genome complexity in terms of size can be determined from DNA renaturation 2. Gene families are represented in the non-repeated fraction of eukaryotic DNA 3. Retrotransposons have an RNA intermediate and require reverse transcriptase 4. Movement of transposons require the enzyme transposase
RNA-RNA hybridization is involved in all of the following processes except:
(All of the above are true) 1.Secondary structure formation in rRNAs and tRNAs 2. Recognition of Shine-Dalgarno sequence in bacterial mRNAs 3. Recognition of 5' and 3' hnRNA splicing sites by the splicesome 4. Correct tRNA association with mRNA codons during translation
Which enzymes or complexes are not associated with mRNA stability and degradation?
(All of the above) 1. Deadenylase 2. Decapping enzyme 3. 5-3' exonuclease 4. exosome
Hershey and Chase used radiolabeled macromolecules to identify the material that contains heritable information. What radioactive material was used to track DNA during this experiment?
32P
Which of the following molecules of RNA would you predict to be most likely to fold into a specific structure as a result of intramolecular base-pairing?
5' - CCCUAAAAAAAAAAAUUUUUUUUUAGG - 3'
You have a piece of DNA that includes the following sequence: 5′-ATAGGCATTCGATCCGGATAGCAT-3′ 3′-TATCCGTAAGCTAGGCCTATCGTA-5′ Which of the following RNA molecules could be transcribed from this piece of DNA?
5'- AUAGGCAUUCGAUCCGGAUAGCAU-3' Use the 3' --> 5' end
Which of the following might decrease the transcription of only one specific gene in a bacterial cell?
A mutation that introduces extensive sequence changes into the DNA that precedes the gene's transcription start site
If you want to engineer a cytoplasmic protein to become a resident RER protein, which of the following amino acid sequences would you need to add?
A signal sequence to its N-terminus and a KDEL sequence to its C-terminus
The adaptor protein _____ is the essential adaptor used in the endocytic pathway, while ____ is important for those vesicles to be formed at the trans Golgi network
AP2;GGA
What GTP-binding protein plays a regulatory role in the formation and disassembly of the COPI coat?
ARF1
Amino acids are charged on their respective t-RNAs through the activity of
Aminoacyl-tRNA synthetases
The piece of RNA below includes the region that codes for the binding site for the initiator tRNA needed in translation. Which amino acid will be on the tRNA that is the first to bind to the A site of the ribosome?
Arginine
What biological process involves surrounding internal organelles like mitochondria with a double membrane for subsequent degradation through the lysosome?
Autophagy
How are most eukaryotic transcription regulators able to affect transcription when their binding sites in enhancers are far from the promoter?
By looping out the intervening DNA between their binding site and the promoter
Which of the following pairs of codons might you expect to be read by the same tRNA as a result of wobble?
CAC and CAU
_____ vessicles move materials from the ER 'forward' to the ERGIC and Golgi complex while ______ move materials from the ERGIC and Golgi 'backward' towards the ER
COPII-coated; COPI-coated
An example of constitutive heterochromatin would be ______
Centromeres and telomeres
Which of the following statements is true?
Chaperone proteins in the mitochondria matrix facilitate the movement of proteins across the outer and inner mitochondrial membranes.
Vesicles from the RER enter the Golgi at the
Cis Golgi network
_____ vesicles internalize materials from the plasma membrane via receptor-mediated endocytosis, while ____ move materials from the Golgi towards the RER
Clathrin-coated; COPI-coated
Concerning pre-RNA processing, which of the following is not true?
Complexes that process hnRNAs assemble on the N-terminal domain of RNA polymerase II
You are a virologist interested in studying the evolution of viral genomes. You are studying two newly isolated viral strains and have sequenced their genomes. You find that the genome of strain 1 contains 25% A, 55% G, 20% C, and 10% T. You report that you have isolated a virus with a single-stranded DNA genome. Based on what evidence can you make this conclusion?
Double stranded genomes have equal amounts of A and T
Which G protein mediates the release of clathrin-coated vesicles from the plasma membrane during receptor-mediated endocytosis?
Dynamin
During eukaryotic pre-mRNA processing, which enzymes are involved in the modification of the 3' end?
Endonuclease and polyA polymerase
Which of the following statements concerning endocytosis and phagocytosis is incorrect?
Engulfment of particles by phagocytosis is driven by microtubule formation in the cell
Which region of the nucleolus is associated with the location of rDNA?
Fibrillar center
Consider the two genes that are next to each other on a chromosome, as arranged in the figure below. Which of the following is true?
Gene A and gene B can be transcribed at different rates, producing different amounts of RNA within the same cell
With respect to genome structure and stability, all of the following statements are true except:
Gene families are represented in the moderately repeated fraction of eukaryotic DNA
Which region of the nucleolus is associated with ribosome assembly?
Granular component
Most eukaryotic cells only express 20-30% of the genes they possess. The formation of heterochromatin maintains the other genes in a transcriptionally silent (unexpressed) state. Which histone modification directs the formation of the most common type of heterochromatin through recruitment of HP1 proteins?
H3 lysine 9 methylation
In terms of eukaryotic DNA fractions, satellite DNAs are found in the ______ fraction and histone genes are found in the _____ fraction
Highly repeated; moderately repeated
During the formation of heterochromatin from euchromatin, what is the order of events that occurs at the level of the histone?
Histone deacetylation; histone methylation; HP1 protein binds to histones
During translation initiation, which initiation factor is a GTP-binding protein required for attachment of the first aminoacyl-tRNA?
IF2 and elF2
What is the order of events that occur for the routing of a protein with a nuclear localization signal into the nucleus?
Importin a/B association with protein, interaction of protein complex with cytoplasmic filament of the nuclear pore, movement of protein complex through the nuclear pore, association of protein complex with Ran-GTP, and transport of importin B to the cytosol via Ran-GTP
The core histones are small, basic proteins that have a globular domain at the C-terminus and a long extended conformation at the N-terminus. Which of the following is not true of the N terminal "tail" of these histones?
It binds to DNA in a sequence specific manner
Which of the following statements concerning the lac operon is not true?
It is a type of repressible operon
What is the role of the nuclear localization sequence in a nuclear protein?
It is bound by cytoplasmic proteins that direct the nuclear protein to the nuclear pore
Which of the following statements concerning endocytosis and phagocytosis is incorrect?
LDL particles are routed to the lysosome via pinocytosis
Which amino acid would you expect a tRNA with the anticodon 5'-CUU-3' to carry?
Lysine
You have discovered a new hn-RNA from a human cell line and want to determine the protein product that is made from the message. What is the predicted protein sequence from this mRNA? Remember to splice out the intron and locate the correct start codon
Met-Gly-Gly-His-Ser-Lys-Leu
What do you predict would happen if you created a tRNA with an anticodon of 5'-CAA-3' that is charged with methionine, and added this modified tRNA to a cell-free translation system that has all the normal components required for translating RNAs?
Methionine would be incorporated into proteins at some positions where leucine should be
What statement concerning histone modification is generally true?
Methylation of amino acids is linked to a heterochromatin state and an euchromatin state
Which of the following statements concerning DNA is true?
Most proteins interact with DNA along its major groove
Transcription regulators bind gene regulatory sequences through:
Non-covalent bonds between amino acid R groups on the surface of the proteins and specific nitrogenous bases in the major groove of DNA
Your friend work in a biotechnology company and has discovered a drugs that blocks the ability of Ran to exchange GDP for GTP. What is the most likely effect of this drug on nuclear transport?
Nuclear transport receptors would be unable to release their cargo in the nucleus
DNA packaging from the lowest level of organization to the highest level is:
Nucleosome, 30-nm fiber, supercoiled loop, mitotic chromosome
During eukaryotic pre-mRNA processing, which enzyme is involved in the last step in the formation of the 5' cap?
RNA methyltransferase
During the unfolded protein response, the protein ______ is activated to cause an inhibition of protein translation, while the protein _____ is cleaved to act like a transcription factor to turn on 'helper' genes.
PERK;ATF6
Formation of clathrin-coated vesicles during receptor-mediated endocytosis is initiated by which of the following molecules?
PI(4,5)P2
After isolating the rough endoplasmic reticulum from the rest of the cytoplasm, you purify the RNAs attached to it. Which of the following proteins do you not expect the RNA from the rough endoplasmic reticulum to encode?
Peripheral proteins on the cytoplasmic face of the lipid bilayer
Where would the protein from the previous question be found in the cell?
Peroxisome
These amino acids line the channel of the nuclear pore to provide a hydrophobic environment
Phenylalanine, glycine
A defect in the lamin A/C gene leads to what disease?
Progeria
Which of the following is not an essential component of the complex that directs a nascent protein into the lumen of the RER?
Protein disulfide isomerase
Which of the following statements about the protein quality control system in the ER is false?
Proteins that are misfolded are degraded in the ER lumen
In terms of DNA structure and composition, which of the following is not true?
Pyrimidines are G and T (They are T and C)
Which of the following choices reflects the appropriate order of locations through which a protein destined for the plasma membrane travels?
RER-->Golgi-->Plasma Membrane
During ribosome docking at the rough endoplasmic reticulum, which of the following act as G proteins to hydrolyze GTP before translation resumes?
SRP and SRP receptor
What GTP-binding protein plays a regulatory role in the formation and disassembly of the COPII coat?
Sar1
Which of the following is not true concerning protein processing?
Secreted proteins (neurotransmitters) are synthesized on "free" ribosomes
Which of the following is a function of the smooth endoplasmic reticulum?
Steroid hormone synthesis, detoxification of organic compounds, and sequestering calcium
A change in nucleotide sequence that does not affect amino acid sequence is said to be _____, whereas a change that causes an amino acid substitution is said to be _______
Synonymous; nonsynonymous
Which model suggests that the Golgi cisternae are transient structures that form at the cis face of the stack
The cisternal maturation model
Which of the following about mRNA half-life is false?
The half-life of most eukaryotic cell mRNAs is >24 hours
Fred Griffith studied two strains of Streptococcus pneumonia, one that causes a lethal infection when injected into mice, and a second that is harmless. He observed that pathogenic bacteria that have been killed by heating can no longer cause an infection. But when these heat-killed bacteria are mixed with live, harmless bacteria, this mixture is capable of infecting and killing a mouse. What did Griffith conclude from this experiment?
The heat-killed pathogenic bacteria "transformed" the harmless strain into a lethal one
What do you predict would happen if you replace the Lac operator DNA from the Lac operon with the DNA from the operator region from the tryptophan operon?
The lac operon will not be transcribed when tryptophan levels are high
Which of the following statements concerning DNA is true?
The melting temperature of DNA increases as its GC content increases
Which of the following is not true about the glycosylation of proteins in the ER?
The oligosaccharide "tree" is made up entirely of glucose
If a bacterium expressed a mutated repressor incapable of binding to the operator of an inducible operon, then what would occur?
The structural genes would always be expressed
In a DNA double helix
The two DNA strands run antiparallel
Human cells contain several different proteins that bind to calcium. They share similar amino acid sequences but are found expressed in different cell types. What can you infer about the genes for these proteins?
They probably arose in evolution by gene duplication
Which of the following is not true concerning transcription factors?
Transcription factors generally act as monomers
The distinct characteristics of different cell types in a multicellular organism result mainly from the differential regulation of the
Transcription of genes transcribed by RNA polymerase II
During translation initiation in eukaryotes, which initiation factor is a GTP-binding protein required for attachment of the first aminoacyl-tRNA?
elF2
Total nucleic acids are extracted from a culture of yeast cells and are then mixed with resin beads to which the polynucleotide 5′-TTTTTTTTTTTTTTTTTTTTTTTTT-3′ has been covalently attached. After a short incubation, the beads are then extracted from the mixture. When you analyze the cellular nucleic acids that have stuck to the beads, which of the following is most abundant?
mRNA
Concerning pre-RNA processing, which of the following is not true?
mRNAs have 3' methyladenine caps and 5' polyG tails
