問題一覧
1
Name the enzyme that forms the peptide bond during proteinsynthesis and define its chemical composition:
Peptidyl transferase, RNA.
2
In mammals, synthesis of mRNA is catalysetl'by:
RNA polymerase II
3
Regarding aminoacyl-tRNA synthetases:
Its specificity is responsible for the high fidelity of translation of genetic code
4
Rifampicin inhibits:
Initiation of transcription
5
Trinuclcotide insertion or deletion result from the deletion or insertion of:
Three nucleotides.
6
The chemical classification of hormones does NOT include:
glucose-containing hormones
7
Which one of the following is NOT the transcription inhibitor in eukaryotes.
Rho factor
8
4.What is the polarity of polypeptide synthesis?
N-terminal to C-terminal direction.
9
In point mutation, replacement of adenine nucleotide by thymine nucleotide is known as
Transition mutation
10
Elevation of intracellular inositol triphosphate (IP2)results in the release of Ca2+ from which of the following organelles
Smooth endoplasmic reticulum
11
1-What is the type of point mutation in which the codon containing the changed base code for a different amino acid
Missense mutation
12
Splicing and differential tissue expressionare:
A result of mRNA editing
13
Vectors are:
Carrier of recombinnt DNA
14
A nonsense mutation is one that:
Creates a premature stop codon.
15
Cystic fibrosis (CF), a hereditary disease that primarily affects the pulmonary and digestive systems, is most commonly caused by:
Deletion of 3 nucleotides.
16
Apo B48 of lipoproteins synthesized in the intestine by
Editing of mRNA in the intestine
17
6-Double strand DNA break repair needs the following proteins:
Ku and DNA-PK proteins
18
Plasmid and cosmid are?
DNA vector
19
The first step in translation is:
Binding of mRNA to the small ribosomal subunit.
20
Thalassemias could occur by all of the following types of mutation except:
Trinucleotide repeat expansion.
21
G-protein-coupled activation of phospholipase C results in
Activation of protein kinase C.
22
If the insertions of three nucleotides occur in a consecutive manner it causes which of the following type of mutation
Trinucleotide repeat expansion mutation.
23
Trans acting elements are:
Protein that bind to promotor to enhance or repress transcription
24
A plasmid is a
Single stranded circular DNA
25
010 A consensus sequnece1 DNA called TATA box is the site for attachment of :
DNA-dependent RNA polymerase
26
3-Exposure of DNA to ultraviolet radiation can lead to the formation of the formation of
Thymine dimers
27
PCR can be used for:
Amplification of DNA from a dried blood spot or one hair follicle to trace the accused person Probes DNA
28
4-Xeroderma pigmentosum results from a defect in:
Excinuclease that removes pyrimdine dimers
29
In point mutation, replacement of adenine nucleotide by guanine nucleotide is known as:
Transversion mutation
30
Q4. The enzyme required for transcription is:
RNA polymerase
31
Trans-acting elements are:
Proteins that are synthesized in cytoplasm andtransported to the nucleus to exert their effect
32
The initiator tRNA is placed within the active 80S complex atwhich of the three canonical ribosomal "sites" during proteinsynthesis?
P site.
33
2-What is the natural function of restriction enzymes?
Protecting bacteria by cleaving the DNA of infecting viruses.
34
Enhancer sequences are:
DNA sequence that act a binding site for activator proteins
35
Q7:Which of the following transcription termination technique has RNA dependent ATPase activity
Rho dependent
36
Gene re-arrangement could result in
a) Increase diversity of proteins from the same genes
37
A silent mutation is highly unlikely to affect protein because:
Multiple codons can code for the same amino acid.
38
Regulation of gene expression by amplification could result in
Increase number of mRNA copies
39
Cortisol crosses the membranes of all cells but affect only target cells because
Intracellular receptors are present only in target cells
40
Adenylate cyclase is activated by
GTP-bearing a-Subunit of G-protein
41
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
42
Actinomycin D binds to:
Double-stranded DNA
43
A Mode of action of steroid hormones involve:
Stimulation of m-RNA transcription
44
All the following statements about bacterial promoters are true except:
TATA box has a high melting temperature
45
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
46
Q1:Which of these subunits of RNA polymerasis totally required to initiate transcription
sigma (o)
47
Wobble base hypothesis is applicable to the.....
3rd base in codon.
48
What kinds of bonds are broken when restriction enzymes cut sticky ends:
Both hydrogen and covalent bonds
49
6-RT-PCR is a method that is used for:
Amplification of mRNA sequences,
50
Q3 Prokaryotic DNA -dependent RNA polymerase is a :
Tetramer
51
Cis acting elements are:
DNA sequence on the same chromosomes of the gene they regulate
52
Which amino acid is the initiating amino acid for essentially all proteins
Methionine.
53
Which of these is not an endocrine gland?
Salivary gland.
54
Endocrine glands differ from exocrine glands in that:
Endocrine glands are ductless and exocrine glandsrelease secretions at the body's surface or into ducts.
55
Huntington disease is an example of:
Trinucleotide repeat expansion
56
2-Which of the following enzymes used in base excision repair?
AP endonuclease
57
Mammalian RNA polymerase III synthesizes
tRNA
58
Q2 Synthesis of RNA frm a DNA template is known as:
transcription
59
The first a.a bind initiator codon bind at:
p site
60
Mammalian RNA polymerase I synthesizes
rRNA
61
Eukaryotic mRNA is described as being:
Monocystronic
62
5-The polymerase chain reaction is a technique that
Selectively replicates DNA
63
the processing of tRNA include all of the following except
Addition of poly A tail
64
Steroid hormones receptor binds to
Hormone response elements in DNA
65
-Hormone receptors are
Proteins
66
Frame shift mutations result from the deletion of:
One or two nucleotides.
67
What is the type of mutation in sickle cell anemia?
Point mutation
68
Transcriptionally active gene is mostly
Hypo methylated
69
RNAi regulating gene expression by:
Increases rate of degradation of mRNA
70
Thyroid hormones, glucocorticoids and gonadal steroids are similar in that each
They have intracellular receptors
71
Epigenetic regulation of gene expression occurs by:
Methylation/demethylation ofCpG at promoter
72
5-All the following statements about xeroderma pigmentosum are true except
Its inheritance is autosomal dominant