o 201 e4 Flashcards
- Which of the following statements is/are true about genes?
a. They exist in different forms.
b. They contain information to produce particular protein or RNA.
c. They contain sequences that determine where genes will be expressed.
d. AOTA
d. AOTA
- Which of the following statements is true?
a. Exons are retained in the mature mRNAs
b. Most human genes have fewer introns than exons
c. Introns are generally found in prokaryotic and eukaryotic genes.
d. Genes are locations in the chromosomes where the specific protein is expressed by the genome.
a. Exons are retained in the mature mRNAs
- Function of histones (non-verbatim)?
a. comprises the nucleosome core
b. composed primarily of acidic AAs
c. regulates gene expression through covalent modification of C-ter tails.
d. NOTA
d. NOTA
- Which of the following is true for the euchromatin?
a. It is a tightly packed type of chromatin
b. It makes up only 10% of the whole human genome
c. It actively transcribes DNA to form mRNA
d. Repeated base sequences found at the ends of the chromosome
c. It actively transcribes DNA to form mRNA
- Why is genomic sequencing other than humans potentially valuable?
a. Diseases of cellular function can be studied in relatively simpler model systems.
b. Comparison of genes between different species can allow prediction of disease-causing mutations.
c. Genes may have similar function in other species, giving us a place to start with functional analysis of similar genes
d. All of the above
d. All of the above
- The whole genome shotgun sequencing approach used by Celera Genomics depend on which if the following?
a. rapid sequencing of thousands of randomly cloned fragments
b. sequencing of random DNA from each chromosome
c. methodical sequencing of few large cloned fragments
d. sequencing of intact chromosome
a. rapid sequencing of thousands of randomly cloned fragments
- What is true regarding single nucleotide polymorphisms (SNP)?
a. An SNP mutation in a gene means that there is more than one allele for that gene.
b. They may bring about change in an amino acid sequence.
c. May occur in non-coding regions of genes.
d. AOTA
d. AOTA
- Which is true regarding personalized genetic medicine?
a. Deliver the most effective treatment plan
b. Optimize disease prevention strategies
c. Reduce treatment-induced complications
d. AOTA
d. AOTA
- Which of the following statements about DNA methylation is TRUE?
a. Increased number of CpG dinucleotides during the evolution of vertebrates increases the chances of gene control by changes in exon sequences
b. DNA is simultaneously methylated and acetylated as a form of genes regulation
c. Methylation of DNA increases the chance of a gene becoming active
d. DNA methylation patterns change throughout the development of an embryo to childbirth
d. DNA methylation patterns change throughout the development of an embryo to childbirth
- Which of the following is a characteristic of a transcripitionally active chromatin
a. Highly condensed
b. Acetylated histone
c. Neither
d. Both
b. Acetylated histone
- As a mesenchymal stem cell undergoes differentiation to terminally differentiated cell, which of the following processes is most likely to happen?
a. Decrease in methylation of CpG islands and increase in acetylation of histones
b. Increase in methylation of CpG islands and increase in acetylation of histones
c. Decrease in methylation of CpG islands and decrease in acetylation of histones
d. Increase in methylation of CpG islands and decrease in acetylation of histones - A certain protein X regulates its own production by
d. Increase in methylation of CpG islands and decrease in acetylation of histones
- A certain protein X regulates its own production by exerting influence on its own pre-mRNA. By binding to its own pre- mRNA, it allows cleavage but not polyadenylation of the pre- mRNA. Which of the following will occur consequently?
a. Transport to the cytoplasm but no translation
b. Errors in RNA splicing
c. Formation of alternative isoforms of the protein
d. Degradation of the pre-mRNA with exonuclease
d. Degradation of the pre-mRNA with exonuclease
- The fibronectin gene is expressed in hepatocytes and fibroblasts. The pre-mRNAs produced in the 2 cells types both contain the exons EIIIA and EIIIB. In the fibroblast, these 2 exons are present and allow the protein to adhere to cell surfaces. In the hepatocyte, the mRNA does NOT contain these 2 exons, allowing the protein product to circulate in the serum. Which type of control of gene expression is this?
a. Transcriptional control
b. mRNA transport
c. Post-transcriptional control
d. Translational control
c. Post-transcriptional control
- Peptide hormones exert their influence on gene expression by initially binding to cell surface receptors. Secondary messengers like cAMP can cause a series of events resulting in the binding of CREB to cAMP-response elements in the DNA. Which type of control of gene expression is this?
a. Epigenetic control
b. Transcriptional control
c. Post-transcriptional control
d. Translational control
b. Transcriptional control
- If the CpG segment just proximal to a promoter of a tumor supressor gene is amplified 100-fold, which of the following is most likely to happen?
a. Increase in the acetylation of the segment
b. Increase in protection against tumorigenesis
c. Deactivation of the MECP2 protein
d. Increase in the likelihood of developing a tumor
d. Increase in the likelihood of developing a tumor
- Which of the following statements about trans-acting factors is TRUE?
a. They are base sequences on the same strand of DNA as the gene that they control
b. They are typically RNA molecules rather than proteins
c. They may either suppress or activate gene expression
d. All of the above statements are FALSE
c. They may either suppress or activate gene expression
- The PER protein has been found to regulate the circardian rhythm. It is active at night and broken down in the morning. Its regulation involves phosphorylation which leads to subsequent ubiquitination and degradation. Identify the regulation involved.
a. Transcriptional control
b. Post-transcriptional control
c. Translational control
d. Post-translational control
d. Post-translational control
- One example of a mechanism by which viruses can cause cancer is the insertion of its genome into the host. An example is the v-src gene of a virus which is identical to the c-src gene in the host genome. Which of the following BEST describes the mechanism by which this particular proto-oncogene becomes an oncogene?
a. deletion in coding sequence
b. gene amplification because of loss of normal regulation
c. point mutation in coding sequence
d. chromosome rearrangement
b. gene amplification because of loss of normal regulation
- Which of the pre-mRNA modifications occur in the nucleus?
a. 5’ end capping with methylguanosine
b. Excision of exons via lariat formation
c. 3’ end tailing with adenylates
d. A and C
A and C
- Which of the following is true about the sequence 5’-GTAG-3’ in relation to pre-mRNA processing?
a. It defines the intron-exon boundary in the primary transcript
b. It defines the exon-intron boundary in the primary transcript.
c. It is found on the coding sequence of the DNA.
d. It is found on the complementary sequence of the DNA.
c. It is found on the coding sequence of the DNA.
- What genetic sequence does the TATA binding protein attach to?
a. Promoter
b. Enhancer
c. Silencer
d. Operator
a. Promoter
- Which is not true about bacterial RNA polymerase?
a. A sigma factor is required for RNA polymerase to bind to the promoter region.
b. Rho-independent termination requires the terminal sequence AAUAAA
c. RNA polymerase can polymerize mRNA, tRNA and rRNA
d. A sigma factor is required for the initiation of transcription
b. Rho-independent termination requires the terminal sequence AAUAAA
- Which of the following RNA does not require ranDTP to transport itself to the cytoplasm?
a. mRNA
b. tRNA
c. miRNA
d. rRNA
a. mRNA
- Which of the following codons codes for an amino acid that has a ringed structure?
a. UGA
b. UGG
c. AUG
d. UAG
b. UGG
- Which of the following is TRUE of eukaryotic ribosomes?
a. 50S + 30S = 70S
b. The mRNA facilitates the attachment of small and large ribosomal units simultaneously.
c. The attached ribosomes in the ER are actively translating.
d. The small ribosomal unit initially attaches to the Shine-Dalgarno sequence of the mRNA.
c. The attached ribosomes in the ER are actively translating.
- Which part of the tRNA do activated amino acids attach to?
a. 5’ end
b. 3’ end
c. D loop
d. Anticodon loop
b. 3’ end
- Which of the following statements is false?
a. First amino acid in prokaryotic translation is formylated methionine
b. Polyadenylate polymerase is anchored to the CPSF
c. Activation of amino acid prior to attaching to tRNAs require GTP hydrolysis
d. Release factors recognize the codon UAA
a. Activation of amino acid prior to attaching to tRNAs require GTP hydrolysis
- Which of the following is true of nucleotide digestion?
a. Initiated by gastric nucleases
b. Facilitated by pancreatic nucleotidase
c. Occurs in the small intestine and stomach
d. End product is nucleosidase
c. Occurs in the small intestine and stomach
- Which of the following statements regarding the regulation of purine biosynthesis is incorrect?
a. The reactions after the branch point in AMP and GMP synthesis are subject to feedback inhibition
b. AMP, XMP, and GMP are negative feedback regulators of the pathway
c. ATP provides energy for GMP production
d. ATP and GTP inhibit the rate limiting step of de novo synthesis
b. AMP, XMP, and GMP are negative feedback regulators of the pathway
- Which of the following is incorrect during salvage purine synthesis is incorrect?
a. Preformed purine monophosphates are the major precusrsors
b. GMP forms Hypoxanthine
c. Less ATP is consumed than in de novo sythesis of bases
d. defect in APRT causes Lesch-Nyhan Syndrome
d. defect in APRT causes Lesch-Nyhan Syndrome
- Which of the following processes is involved in the formation of deoxyribonucleotides?
a. Incorporation of dietary deoxyribose to purine and pyrimidine bases
b. Attachment of deoxyribose to preformed bases via phosphoribosyl transferase
c. Synthesis of deoxyribose by the PPP
d. Reduction of C2 of the 4 different ribonucleotide diphosphate
d. Reduction of C2 of the 4 different ribonucleotide diphosphate
- Which of the following statements is NOT TRUE regarding the catabolism of nucleotides?
a. B-aminoisobutyrate is an end product of thymine nucleotide degradation
b. B-alanine is the end product of cytosine degradation
c. A defect in the adenosine catabolic enzyme leads to severe combined immune deficiency syndrome
d. Less severe immunodeficiency may be due to defective pyrimidine nucleoside phosphorylase
b. B-alanine is the end product of cytosine degradation
- What pathway is affected in severe combined immunodeficieny (scid)
a. purine synthesis
b. purine salvage pathway
c. purine catabolism
d. pyrimidine degradation
c. purine catabolism
- A defect in the activity of this enzyme will predispose to the development of goiter
a. HGPRT
b. Xanthine oxidase
c. PRPP Synthetase
d. A & B only
a. HGPRT
- The replicative DNA polymerase ensures that the correct base pair interacts by which of the following mechanisms?
a. Interacting with and recognizing the incoming dNTP
b. Accomplishing fast catalysis in the presence of the correct base pair
c. Accomplishing slow catalysis in the presence of the correct base pair
d. Mechanism still unknown
b. Accomplishing fast catalysis in the presence of the correct base pair
- The _____________ groove is less information-rich; ____________ makes use of this to carry out its primary function
a. Major; DNA polymerase
b. Minor; DNA polymerase
c. Major; exonuclease
d. Minor; exonuclease
e. Major + Minor; DNA P. + exonuclease
v
b. Minor; DNA polymerase
- Lysine and arginine are part of the O-helix of the DNA polymerase, along with metal cations. Which statement is not true?
a. Lysine, arginine, and metal cations are all positively charged
b. Metal cations interact with and help position the alpha, beta, and gamma phosphates
c. Lysine is critical in making stacking interactions with incoming dNTP
d. Lysine and arginine interact with and help position the alpha, beta, and gamma phosphates
b. Metal cations interact with and help position the alpha, beta, and gamma phosphates
- Proofreading exonucleases are critical in the fidelity of DNA synthesis. Which statement/s is/are incorrect?
a. The proofreading exonucleases can be part of the same polypeptide chain as the DNA polymerase
b. The proofreading exonucleases increases the fidelity of DNA synthesis about 100 fold
c. The proofreading exonucleases degrades short stranded DNA starting at the 5’ end
d. The proofreading exonucleases degrades short stranded DNA starting at the 3’ end
c. The proofreading exonucleases degrades short stranded DNA starting at the 5’ end
- Based on the structural properties of replicative DNA helicase, which of the statements is supported by these structural properties?
a. The replicative DNA helicase initiates when binded to single stranded DNA not double stranded DNA.
b. The replicative DNA helicase initiates when binded to double stranded DNA
c. All 6 subunits are in the same nucleotide bound or unbound state at the same time
d. ATP hydrolysis is the key step in replicative DNA helicase translocation along the DNA strand.
a. The replicative DNA helicase initiates when binded to single stranded DNA not double stranded DNA.
- Select all that characterize SSB protein
a. Prevalent in both leading strand and lagging strand template
b. Promote primase activity
c. Prevent reannealing between leading strand template and lagging strand template
d. Prevent annealing between complementary bases of leading strand template
b. Promote primase activity