問題一覧
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Q1:Which of these subunits of RNA polymerasis totally required to initiate transcription
sigma (o)
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Q2 Synthesis of RNA frm a DNA template is known as:
transcription
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Q3 Prokaryotic DNA -dependent RNA polymerase is a :
Tetramer
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Q4. The enzyme required for transcription is:
RNA polymerase
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Mammalian RNA polymerase I synthesizes
rRNA
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Mammalian RNA polymerase III synthesizes
tRNA
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Q7:Which of the following transcription termination technique has RNA dependent ATPase activity
Rho dependent
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In mammals, synthesis of mRNA is catalysetl'by:
RNA polymerase II
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Which one of the following is NOT the transcription inhibitor in eukaryotes.
Rho factor
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010 A consensus sequnece1 DNA called TATA box is the site for attachment of :
DNA-dependent RNA polymerase
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Rifampicin inhibits:
Initiation of transcription
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The DNA chain acting as a template for RNA synthesize has the following order of bases(AGCTTCGA) what will be the order of bases in mRNA
UCGAAGCU
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Actinomycin D binds to:
Double-stranded DNA
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All the following statements about bacterial promoters are true except:
TATA box has a high melting temperature
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Although each specific tRNA differs from the others in itssequence of nucleotides, all tRNA molecules contain a base paired stem that terminates in the sequence CCA at
3' terminal
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the processing of tRNA include all of the following except
Addition of poly A tail
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Regarding aminoacyl-tRNA synthetases:
Its specificity is responsible for the high fidelity of translation of genetic code
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Wobble base hypothesis is applicable to the.....
3rd base in codon.
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The first step in translation is:
Binding of mRNA to the small ribosomal subunit.
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The first a.a bind initiator codon bind at:
p site
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Eukaryotic mRNA is described as being:
Monocystronic
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The initiator tRNA is placed within the active 80S complex atwhich of the three canonical ribosomal "sites" during proteinsynthesis?
P site.
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Name the enzyme that forms the peptide bond during proteinsynthesis and define its chemical composition:
Peptidyl transferase, RNA.
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Which amino acid is the initiating amino acid for essentially all proteins
Methionine.
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4.What is the polarity of polypeptide synthesis?
N-terminal to C-terminal direction.
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Cis acting elements are:
DNA sequence on the same chromosomes of the gene they regulate
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Trans acting elements are:
Protein that bind to promotor to enhance or repress transcription
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Apo B48 of lipoproteins synthesized in the intestine by
Editing of mRNA in the intestine
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Enhancer sequences are:
DNA sequence that act a binding site for activator proteins
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Trans-acting elements are:
Proteins that are synthesized in cytoplasm andtransported to the nucleus to exert their effect
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Splicing and differential tissue expressionare:
A result of mRNA editing
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RNAi regulating gene expression by:
Increases rate of degradation of mRNA
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Transcriptionally active gene is mostly
Hypo methylated
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Epigenetic regulation of gene expression occurs by:
Methylation/demethylation ofCpG at promoter
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Regulation of gene expression by amplification could result in
Increase number of mRNA copies
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Gene re-arrangement could result in
a) Increase diversity of proteins from the same genes
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2-Which of the following enzymes used in base excision repair?
AP endonuclease
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3-Exposure of DNA to ultraviolet radiation can lead to the formation of the formation of
Thymine dimers
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4-Xeroderma pigmentosum results from a defect in:
Excinuclease that removes pyrimdine dimers
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5-All the following statements about xeroderma pigmentosum are true except
Its inheritance is autosomal dominant
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6-Double strand DNA break repair needs the following proteins:
Ku and DNA-PK proteins
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1-What is the type of point mutation in which the codon containing the changed base code for a different amino acid
Missense mutation
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What is the type of mutation in sickle cell anemia?
Point mutation
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A nonsense mutation is one that:
Creates a premature stop codon.
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A silent mutation is highly unlikely to affect protein because:
Multiple codons can code for the same amino acid.
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In point mutation, replacement of adenine nucleotide by guanine nucleotide is known as:
Transversion mutation
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In point mutation, replacement of adenine nucleotide by thymine nucleotide is known as
Transition mutation
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Frame shift mutations result from the deletion of:
One or two nucleotides.
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Trinuclcotide insertion or deletion result from the deletion or insertion of:
Three nucleotides.
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Cystic fibrosis (CF), a hereditary disease that primarily affects the pulmonary and digestive systems, is most commonly caused by:
Deletion of 3 nucleotides.
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If the insertions of three nucleotides occur in a consecutive manner it causes which of the following type of mutation
Trinucleotide repeat expansion mutation.
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Huntington disease is an example of:
Trinucleotide repeat expansion
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Thalassemias could occur by all of the following types of mutation except:
Trinucleotide repeat expansion.
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Plasmid and cosmid are?
DNA vector
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2-What is the natural function of restriction enzymes?
Protecting bacteria by cleaving the DNA of infecting viruses.
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A plasmid is a
Single stranded circular DNA
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What kinds of bonds are broken when restriction enzymes cut sticky ends:
Both hydrogen and covalent bonds
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5-The polymerase chain reaction is a technique that
Selectively replicates DNA
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6-RT-PCR is a method that is used for:
Amplification of mRNA sequences,
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PCR can be used for:
Amplification of DNA from a dried blood spot or one hair follicle to trace the accused person Probes DNA
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Vectors are:
Carrier of recombinnt DNA
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Endocrine glands differ from exocrine glands in that:
Endocrine glands are ductless and exocrine glandsrelease secretions at the body's surface or into ducts.
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Which of these is not an endocrine gland?
Salivary gland.
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The chemical classification of hormones does NOT include:
glucose-containing hormones
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-Hormone receptors are
Proteins
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Steroid hormones receptor binds to
Hormone response elements in DNA
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A Mode of action of steroid hormones involve:
Stimulation of m-RNA transcription
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Adenylate cyclase is activated by
GTP-bearing a-Subunit of G-protein
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G-protein-coupled activation of phospholipase C results in
Activation of protein kinase C.
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Elevation of intracellular inositol triphosphate (IP2)results in the release of Ca2+ from which of the following organelles
Smooth endoplasmic reticulum
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Cortisol crosses the membranes of all cells but affect only target cells because
Intracellular receptors are present only in target cells
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Thyroid hormones, glucocorticoids and gonadal steroids are similar in that each
They have intracellular receptors