7th-Biochemistry-Exam-DNA-and-RNA-Metabolism-Batch-2025 COPY Flashcards
1
Q
1.True about the non-template strand except:
A. Strand that is transcribed
B. Also termed coding strand
C. Corresponds exactly to the sequence of RNA primary transcript except T for U
D. None of the above
A
A. Strand that is transcribed
2
Q
2.The product of DNA transcription is called:
A. Mature mRNA
B. Introns
C. Primary transcript
D. Exons
A
C. Primary transcript
3
Q
- Nonprotein coding RNA that participates in mRNA splicing:
A. miRNA
B. siRNA
C. snRNA
D. lncRNA
A
C. snRNA
4
Q
4.The most abundant of all types of RNA comprising about 80% of the total:
A. mRNA
B. tRNA
C. snRNA
D. rRNA
A
D. rRNA
5
Q
5.Similarities of DNA and RNA synthesis include the following except:
A. The general steps of initiation, elongation and termination with 5’ to 3’ polarity
B. Large multicomponent initiation complexes
C. Both have highly active efficient proofreading function
D. Adherence to Watson-Crick base-pairing principles
A
C. Both have highly active efficient proofreading function
6
Q
6.This includes the promoter, RNA-coding region and a terminator:
A. Transcription unit
B. Primary transcript
C. 5’ Flanking sequences
D. 3’ Flanking sequences
A
A. Transcription unit
7
Q
7.The RNA polymerase that has intermediate sensitivity to alpha-amanitin:
A. Pol I
B. Pol II
C. Pol III
D. Pol IV
A
C. Pol III
8
Q
8.The major product/products of RNA Polymerase I is:
A. rRNA
B. mRNA, lncRNA,miRNA,snRNA
C. tRNA, 5s RNA
D. 45S RNA
A
A. rRNA
9
Q
9.RNA polymerase attaches to this site to start the initiation process:
A. Guanosine triphosphate cap
B. Enhancer
C. Primer
D. Promoter
A
D. Promoter
10
Q
10.All nucleotides upstream of the site of transcription termination are termed:
A. 5’ Flanking sequences
B. 3’ Flanking sequences
C. Pre-initiation complex
D. Closed complex
A
A. 5’ Flanking sequences
11
Q
11.The type of RNA polymerase that catalyzes the synthesis of mRNA:
A. Pol I
B. Pol II
C. Pol III
D. Pol IV
A
B. Pol II
12
Q
12.The TATA box in eukaryotes is located:
A. 10 bp upstream from the transcription start site (TSS)
B. 25-30 bp upstream from TSS
C. 35 bp upstream from the TSS
D. 5 bp upstream from the TSS
A
B. 25-30 bp upstream from TSS
13
Q
13.The termination protein is also called:
A. Psi factor
B. Sigma factor
C. Alpha factor
D. Rho factor
A
D. Rho factor
14
Q
14.In some mRNA encoding genes that lack a consensus TATA box, this directs the RNAP
A. Downstream promoter element
B. Enhancers
C. General transcription factors
D. Primer
A
A. Downstream promoter element
15
Q
15.The general transcription factor (GTF) that binds to the TATA box promoter element:
A. TFIIA
B. TFIIB
C. TFIIC
D. TFIID
A
D. TFIID
16
Q
16.Phosphorylation of Pol II results to:
A. Increased activity
B. Reduced activity
C. No change
D. Static activity
A
A. Increased activity
17
Q
17.On certain eukaryotic genes, transcription machinery cannot access the promoter because they are wrapped in:
A. Spliceosomes
B. Ribosomes
C. Nucleosomes
D. Ribozymes
A
C. Nucleosomes
18
Q
18.Processing of mRNA primarily occurs in the:
A. Cytoplasm
B. Ribosomes
C. Nucleus
D. Nucleolus
A
C. Nucleus
19
Q
19.The RNA sequence that appears in mature RNAs:
A. Exons
B. Introns
C. Cap
D. Tail
A
A. Exons
20
Q
20.Intervening sequences of DNA that neither appear in mature mRNA nor contribute to the genetic information:
A. Exons
B. Introns
C. Cap
D. Tail
A
B. Introns
21
Q
21.Removal of intervening sequences and splicing together of final sequences are done by:
A. Spliceosome
B. Nucleosome
C. Ribosome
D. None
A
A. Spliceosome
22
Q
22.In mammalian cells, the three rRNA molecules are transcribed as part of this single large precursor molecule:
A. 40S
B. 32S
C. 45S
D. 24S
A
C. 45S
23
Q
23.The precursor rRNA molecule is processed in the:
A. Nucleus
B. Nucleolus
C. Ribosome
D. Mitochondria
A
B. Nucleolus
24
Q
24.At the 5’end, mRNA molecules are capped with:
A. Poly (A) tail
B. TATA cap
C. 7-methylguanosine cap
D. GCCT tail
A
C. 7-methylguanosine cap
25
25. RNA can also act as a catalyst in the form of:
A. Lysozymes
B. Ribozymes
C. Kinases
D. Topoisomerase
B. Ribozymes
26
26.Which of the following best describes semiconservative replication?
A. replication of DNA takes place at S phase of the cell cycle
B. a DNA molecule is a hybrid of an old strand and one new strand
C. number of DNA molecules is doubled with every other replication
D. replication of DNA never takes place with 100% accuracy
B. a DNA molecule is a hybrid of an old strand and one new strand
27
27.What consists of the final product of DNA replication?
A. mRNA, tRNA, and rRNA molecules
B. a wide variety of proteins
C. DNA molecule
D. 2 DNA molecules, each of which contains one new & one old DNA strand
D. 2 DNA molecules, each of which contains one new & one old DNA strand
28
28.Which method/technique was used by Messelson and Stahl to prove semi-conservative manner of replication?
A. equilibrium density gradient centrifugation
B. isopycnic centrifugation
C. differential centrifugation
D. differential radioisotope labeling
A. equilibrium density gradient centrifugation
29
29.Which of the following cause the unwinding of the DNA double helix in E. coli?
A. Dna A
B. Dna B
C. Dna C
D. Dna G
B. Dna B
30
30.Which describes the replication fork?
A. only seen in bacterial cells
B. a Y-shaped structure representing the separated strands of DNA to be replicated simultaneously
C. a site where one DNA strand serves as a template, but the other strand is not replicated
D. is created by the action of the enzyme RNA polymerase
B. a Y-shaped structure representing the separated strands of DNA to be replicated simultaneously
31
31.In replication, once the DNA strands have been separated, which prevents the renaturation of the DNA strands?
A. DNA helicase enzyme
B. SSB proteins
C. DNA polymerases
D.ATP
B. SSB proteins
32
32.Which enzymes form breaks in the DNA molecules preventing the formation of knots in the DNA helix during replication?
A. topoisomerases
B. DNA polymerases
C. RNA polymerases
D. DNA ligases
A. topoisomerases
33
33.Which of the following adds new nucleotides to a growing DNA chain?
A. DNA polymerase
B. DNA helicase
C. primase
D. RNA polymerase
A. DNA polymerase
34
34.Why does DNA synthesis only proceed in the 5´ to 3´ direction?
A. DNA polymerases can only add nucleotides to the 3´ end of a polynucleotide strand
B. the 3´ end of the polynucleotide molecule is more electronegative than the 5´ end
C. that is the direction in which the two strands of DNA unzip
D. that is the only direction that the polymerase can be oriented
A. DNA polymerases can only add nucleotides to the 3´ end of a polynucleotide strand
35
35.Which begins the 5´ end of each Okazaki fragments?
A. the same RNA primer that began synthesis on the leading strand
B. a DNA primer binding to the template DNA
C. DNA polymerase binding to the template DNA
D. a separate RNA primer
D. a separate RNA primer
36
36.What does a primase carry out in replication?
A. introducing nicks into the DNA double strand in order to prevent the formation of knots
B. hydrolyzing ATP to facilitate DNA unwinding
C. synthesizes short strands of RNA at the site of replication initiation
D. forming a replication fork in the DNA double helix
C. synthesizes short strands of RNA at the site of replication initiation
37
37.Which protein seals the nick in between Okazaki fragments?
A. RNA polymerase
B. DNA ligase
C. DNA polymerase
D. RNA ligase
B. DNA ligase
38
38.How is the chromosome of a bacterial cell replicated?
A. linear DNA molecule is replicated from multiple origins of replication bidirectionally.
B. linear DNA molecule is replicated from one origin of replication bidirectionally.
C. circular DNA molecule is replicated from one origin of replication bidirectionally
D. circular DNA molecule is replicated from one origin of replication Unidirectionally
C. circular DNA molecule is replicated from one origin of replication bidirectionally
39
39.Which is the manner by which eukaryotic cells replicate their chromosomes?
A. the linear DNA, from multiple origins of replication bidirectionally
B. the linear DNA, from one origin of replication bidirectionally
C. the circular DNA from multiple origins of replication bidirectionally
D. the circular DNA from one origin of replication bidirectionally
A. the linear DNA, from multiple origins of replication bidirectionally
40
40.Which is an important feature of the E. coli DNA polymerase III?
A. can initiate replication without a primer
B. is efficient at nick translation
C. is the major polymerizing enzyme in DNA replication
D. represents over 90% of the DNA polymerase activity in E. coli cells
C. is the major polymerizing enzyme in DNA replication
41
41.The 5' to 3' exonuclease activity of E. coli
DNA polymerase I is involved in:
A. synthesis of the primers at the DNA replication origin
B. synthesizing the lagging strand
C. proofreading of the replication process
D. polymerizing the gaps in between Okazaki fragments
D. polymerizing the gaps in between Okazaki fragments
42
42.Which enzyme removes the RNA primer during replication?
A. DNA polymerase IV
B. DNA polymerase I
C. DNA ligase
D. DNA polymerase II
B. DNA polymerase I
43
43.The lagging daughter strand of DNA is synthesized in what appears to be the “wrong” direction. How is this synthesis accomplished?
A. synthesizing short Okazaki fragments in a 5’ – to 3’ direction & forming a loop toward the replication forks
B. synthesizing one short RNA primer to initiate DNA replication
C. using DNA polymerase II to remove RNA primers from Okasaki fragments
D. All of the choices
A. synthesizing short Okazaki fragments in a 5’ – to 3’ direction & forming a loop toward the replication forks
44
44.Which differentiate Pol I from Pol III?
A. Pol I is an RNA polymerase, while Pol III is a DNA polymerase
B. Pol I has a 3'-5' exonuclease activity, the other does not
C. Pol I has a lower turnover number, the other has 9000 as its turn over #
D. Pol I utilizes RNA primers, the other does not
C. Pol I has a lower turnover number, the other has 9000 as its turn over #
45
45.During replication in E. coli, unwinding of DNA is caused by _________ forming positive supercoils which are removed by
_________.
A. DNA ligase, DNA Gyrase
B. DnaB, DNA polymerase
C. DnaB, DNA Gyrase
D. DnaA, DNA Gyrase
C. DnaB, DNA Gyrase
46
46.What are the more common secondary structures that might form in the separated DNA strands of replication?
A. basic helix-loop-helix
B. Greek key
C. beta meander
D. stem-loops
D. stem-loops
47
47.Which is an important feature of a plasmid?
A. contains two or more ori Cs
B. extrachromosomal DNA autonomously replicating
C. usually contains one antibiotic-resisitant gene
D. replicates together with the replication of the host genome
B. extrachromosomal DNA autonomously replicating
48
48.What is the enzyme used in Polymerase Chain Reaction?
A. ATP synthase
B. Taq Polymerase
C. DNA ligase
D. Primase
B. Taq Polymerase
49
49.Which is the process whereby foreign DNA fragments from the surrounding medium is taken up by the a cell?
A. transformation
B. conjugation
C. transduction
D. transversion
A. transformation
50
50.Which of the following statements about forensic analysis of DNA is correct?
A. A DNA profile using short tandem repeats is unique to an individual.
B. Forensic analysis makes use of SNPs in coding sequences to distinguish between individuals.
C. PCR is used for DNA profiling (DNA fingerprinting).
D. DNA fingerprinting cannot be used for paternity testing.
C. PCR is used for DNA profiling (DNA fingerprinting).
51
51. Which of the following is NOT required for a PCR reaction?
A. A thermostable DNA polymerase
B. Dideoxy-dNTPs (ddNTPs)
C. Primers
D. Template DNA
B. Dideoxy-dNTPs (ddNTPs)
52
52.From where are restriction enzymes are derived?
A. plant cells
B. bacteria
C. viruses they attack
D. all of the choices
B. bacteria
53
53.Which is the use restriction enzymes in their natural environment?
A. protect virus from bacterial infection
B. cut DNA at specific sites
C. cleave DNAs producing sticky ends & blunt ends
D. cut both DNA and vector sequences
B. cut DNA at specific sites
54
54.Which is the biological role of restriction enzymes in their natural environment?
A. aid recombinant DNA research
B. degrade foreign DNA that enters a bacterium
C. make bacteria resistant to antibiotics
D. restrict the damage to DNA by ultraviolet light
B. degrade foreign DNA that enters a bacterium
55
55.To be able to insert a foreign DNA into a vector, both must:
A. have identical DNA sequences
B. originate from the same cell type
C. be cut by the same restriction endonuclease
D. be of the same length
C. be cut by the same restriction endonuclease
56
56.Which is an example of a restriction fragment length polymorphism(RFLP)?
A. a fragment of DNA generated by an Eco RI on DNA at a different sequence that Hind III
B. different length of DNA resulting from loss or gain of a restriction sites
C. three base deletion on the gene that codes for the cystic fibrosis protein resulting into most cases but in other cases, other mutations are involved
D. fragments generated by Sal I cutting DNA at the same site as that of Eco RI
B. different length of DNA resulting from loss or gain of a restriction sites
57
57.What is the consequence of adding dideoxy NTPs in a PCR reaction mixture?
A. polymerization will stop once the dideoxy NTPs are incorporated
B. formation of incomplete segments of DNA will be generated
C. inverted repeats are inserted on the DNA clones
D. production of overhangs on clones
A. polymerization will stop once the dideoxy NTPs are incorporated
58
58.In the laboratory, which introduces recombinant plasmids are into bacterial cells?
A. electrophoresis – a gentle low-voltage gradient draws the DNA into the cell.
B. infection with a bacteriophage that carries the plasmid.
C. mixing plasmids with an extract of broken cells.
D. transformation – heat shock of the cells incubated with plasmid DNA in the presence of CaCl2.
D. transformation – heat shock of the cells incubated with plasmid DNA in the presence of CaCl2.
59
59.What is the correct sequence of events in Southern blotting?
A. Hybridization of DNA fragments with a labelled probe sequence followed by separation by electrophoresis and then transfer to a membrane.
B. Separation of DNA fragments by electrophoresis followed by hybridization with a labelled probe sequence and then transfer to a membrane.
C. Separation of DNA fragments by electrophoresis followed by transfer to a membrane and then hybridization with a labelled probe sequence.
D. Transfer of DNA fragments to a membrane followed by separation by electrophoresis and then hybridization with a labelled probe sequence.
C. Separation of DNA fragments by electrophoresis followed by transfer to a membrane and then hybridization with a labelled probe sequence.
60
60.Nucleic acid hybridization can detect any given DNA or RNA sequence in a mixture of nucleic acid fragments. Which principle applies?
A. that a single strand of DNA or RNA will form a double helix only with another nucleic acid strand of an identical nucleotide sequence
B. that a single strand of DNA or RNA will form a double helix only with another nucleic acid strand of the complementary nucleotide sequence
C. that a single strand of DNA or RNA will form covalent bonds with the sugar-phosphate backbone of the target nucleic acid
D. None of the above
B. that a single strand of DNA or RNA will form a double helix only with another nucleic acid strand of the complementary nucleotide sequence
61
61.What does the term DNA cloning refer to?
A. Ligating a DNA fragment of interest into a vector, such as a plasmid
B. Cutting DNA molecules with restriction nucleases
C. The act of making many identical copies of a DNA molecule
D. Putting a foreign gene into a cell
C. The act of making many identical copies of a DNA molecule
62
62.In the PCR, what is used to separate the two strands of a double-stranded DNA molecule?
A. High temperature
B. Excess concentration of salts
C. Change in pH
D. Sonication
A. High temperature
63
63.Which of the following statements about the polymerase chain reaction (PCR) is false?
A. DNA amplified by PCR can be cloned.
B. DNA is amplified at many points within a cellular genome
C. Newly synthesized DNA must be heat-denatured before the next round of DNA synthesis begins.
B. DNA is amplified at many points within a cellular genome
64
64.Which is the most convenient cloning vector with which to introduce foreign DNA into E. coli?
A. cosmid
B. bacteriophage
C. plasmid
D. yeast "ARS" sequence
C. plasmid
65
65.Dideoxynucleotide method of DNA sequencing is used to:
A. amplify a set of DNA.
B. determine the amino acid sequence of a protein in vitro.
C. denature a set of DNA.
D. sequence the nucleotides of any purified DNA fragment.
D. sequence the nucleotides of any purified DNA fragment.
66
66.Which the most important discovery that lead to the development of the Recombinant DNA Technology?
A. double helix model of Watson & Crick
B. isolation of restriction endonucleases
C. discovery of DNA ligase enzyme
D. discovery of plasmids
B. isolation of restriction endonucleases
67
67.Which of the following enzymes allows scientists to join together two DNA fragments?
A. DNA polymerase
B. DNA ligase
C. Restriction nuclease
D. DNA helicase
B. DNA ligase
68
68.What does a DNA library consist of?
A. collection of cloned DNA fragments in a bacterial culture
B. database of gene sequences from an organism’s genome
C. collection of Vector DNA, cleaved by a restriction nuclease
D. catalog of commercially available DNA probes
A. collection of cloned DNA fragments in a bacterial culture
69
69.Which of the following does not apply to the construction or use of a DNA library?
A. Determining the location of a particular DNA sequence in a DNA library requires a suitable hybridization probe.
B. Genomic libraries are better for expressing gene products than cDNA libraries
C. Many segments of DNA from a cellular genome are cloned.
D. Specialized DNA libraries can be made by cloning DNA copies of mRNAs.
B. Genomic libraries are better for expressing gene products than cDNA libraries
70
70.Which of the following genetic libraries lacks introns and regulatory sequences?
A. genomic library
B. cDNA library
C. RNA library
D. DNA library
B. cDNA library
71
71.When making a DNA library from a starting material of mRNA, which enzyme is utilized?
A. RNA polymerase
B. DNA polymerase
C. Reverse transcriptase
D. Restriction nuclease
C. Reverse transcriptase
72
72.Majority of infertility cases caused by genetic abnormalities can be factored from?
A. Males
B. Females
C. Both
D. None
A. Males
73
73.When does oocyte depletion occur?
A. Fetal period
B. Puberty period
C. Early adulthood period
D. Post menopausal period
A. Fetal period
74
74.Most common cause of female infertility due to fetal lethality and/or recurrent miscarriage (65%)?
A. Thrombophilic conditions in coagulation factor II gene
B. X chromosome aberration
C. Fetal aneuploidy
D. Placental insufficiency due to placental annexin 5
C. Fetal aneuploidy
75
75.What are the frequent cause of ovarian dysgenesis in female infertility?
A. Single gene defects
B. Large alterations
C. Balanced rearrangements
D. Submicroscopic alterations
B. Large alterations
76
75.What are the frequent cause of ovarian dysgenesis in female infertility?
A. Single gene defects
B. Large alterations
C. Balanced rearrangements
D. Submicroscopic alterations
B. Large alterations
77
76.What are the most common facial clinical features of fragile X syndrome?
A. Long narrow face
B. Macrocephaly
C. High-arched palate
D. Prominent jaw
D. Prominent jaw
78
77.What is the most important clinical abnormality associated with the FXS?
A. Macrocephaly
B. Global developmental delay
C. Cardiovascular disease
D. Epilepsy
B. Global developmental delay
79
78.Important mechanism in epigenetics of glucose metabolism in life, associated with IGF2?
A. Histones modification
B. Non-coding mRNA
C. DNA methylation
D. Sib-pairs
C. DNA methylation
80
79.Most common cause of transposon activity and silencing?
A. Histones modification
B. Non-coding mRNA
C. DNA methylation
D. Sib-pairs
B. Non-coding mRNA
81
80.Persistent hunger during pregnancy or obesity will cause changes in?
A. Histones modification
B. Non-coding mRNA
C. DNA methylation
D. Sib-pairs
C. DNA methylation
82
81.Epigenetic regulation of the structure and function of the chromatin causing metabolic syndrome is by?
A. Histones modification
B. Non-coding mRNA
C. DNA methylation
D. Sib-pairs
A. Histones modification
83
82.Transcription is a step in protein synthesis where a molecule of ________ is made from DNA.
A. tRNA
B. mRNA
C. rRNA
D. protein
B. mRNA
84
83.Translation is a step in protein synthesis where mRNA is used to make a _______?
A. tRNA
B. mRNA
C. rRNA
D. protein
D. protein
85
84.Which RNA is the “copy” of the DNA that is used to specify the sequence of amino acids in protein?
A. tRNA
B. mRNA
C. rRNA
D. all of the above
B. mRNA
86
85.What is the sequence of amino acids if the DNA sequence reads 5’AATTGGCTCGGACAT3’?
A. Leu – Ser – Val – Pro - Val
B. Met - Val – Pro - Ser - Leu
C. Ile – Pro – Glu – Ser - Met
D. Met – Ser – Glu – Pro – Ile
D. Met – Ser – Glu – Pro – Ile
87
86.Which of the following is characteristic of eukaryotic translation but absent in prokaryotes?
A. Polyribosomal assembly
B. Non-overlap of transcription and translation process sequences
C. Intranuclear location
D. All of the above
B. Non-overlap of transcription and translation process sequences
88
87.What is the purpose of the 30 s ribosomal subunit in prokaryotes?
A. tRNA attachment
B. Synthesis of peptide linkages
C. Formation of complex with mRNA
D. Translation termination
C. Formation of complex with mRNA
89
88.What happens if the Shine-Dalgarno sequence is altered?
A. Bacterial translation cannot be initiated
B. A Silent mutation occurs
C. Eukaryotes can no longer form peptide linkages
D. Transcription overlaps with translation
A. Bacterial translation cannot be initiated
90
89.The wobble phenomenon is defined by which of the following?
A. Base pairing that does not follow the Watson-Crick rules
B. Loose pairing between the codon and anticodon of eukaryotes
C. Intron and extron base pairing scheme
D. Jumping genes
A. Base pairing that does not follow the Watson-Crick rules
91
90.What is the function of aminoacyl tRNA synthethase?
A. Peptide bond formation
B. Attachment of the tRNA to the A site
C. Proper tRNA-amino acid pairing
D. Translation initiation
C. Proper tRNA-amino acid pairing
92
91.Which of the following is a start codon?
A. UAA
B. AUG
C. UGA
D. AAU
B. AUG
93
92.A multinational biotechnology outfit formed by a graduate of JFSM is studying a new antibiotic that alters the 50S ribosomal subunit structure. When this antibiotic is added to an in-vitro protein synthesis system that is translating the mRNA sequence AUGUUUUUUUAG, only methionine is formed. What step in protein synthesis was probably affected?
A. Initiation
B. Elongation
C. Termination
D. Folding
B. Elongation
94
93.Which of the following is a post-translational modification?
A. Lysine Hydroxylation
B. 5’ cap insertion
C. Poly-A Tail formation
D. Rho factor attachment
A. Lysine Hydroxylation
95
94.The genetic code is said to be degenerate because:
a. Only one codon can specify for an amino acid
b. Only one tRNA can specify for an amino acid
c. One amino acid can specify for only one codon
d. One amino acid can be specified by more than one codon
d. One amino acid can be specified by more than one codon
96
95.The genetic code is unambiguous because:
a. Only one codon can specify for an amino acid
b. Only one amino acid is indicated for one codon
c. One amino acid can specify for only one codon
d. One amino acid can be specified by more than one codon
b. Only one amino acid is indicated for one codon
97
96.The amino acid that has 6 codons:
a. Glysine
b. Histidine
c. Leucine
d. Proline
c. Leucine
98
97.Which of the following antibiotics inhibits protein synthesis?
A. erythromycin
B. rifampicin
C. quinolone
D. all of the above
A. erythromycin
99
98.Which of the following inhibits protein synthesis in both prokaryotes and eukaryotes?
A. diphtheria toxin
B. puromycin
C. ricin
D. cycloheximide
B. puromycin
100
99.Which of the following is the first codon read during translation?
A. UAG
B. AUG
C. GAG
D. AAG
B. AUG
101
100.Each amino acid is joined to the correct tRNA by this enzyme ______________:
A. Aminoacyl-tRNA synthetase
B. RNA polymerase
C. DNA polymerase
D. Ribosomal oxygenase
A. Aminoacyl-tRNA synthetase
