R4RIN – MCQs, Mock Tests | Biochemistry Biochemistry MCQS PAPER SET 5

 Which of the following species lack a 'classical' histone H1?

1. Saccharomyces cerevisiae
2. Strongylocentrotus purpuratus
3. Xenopus laevis
4. Arabidopsis thaliana

✅ Correct Answer: 1

Which of the following is correct?

1. Replication starts at a single origin
2. Replication is bidirectional
3. Replication is semi conservative
4. All of the above

✅ Correct Answer: 4

Which of the following are short nucleotides strands made by DNA polymerase working in the opposite direction of the replication fork?

1. Leading strands
2. Okazaki fragments
3. Primers
4. Lagging strand

✅ Correct Answer: 2

Which of these drugs bind to DNA and cuts it, producing hydroxyl radicals?

1. Bleomycin
2. Erythromycin
3. Tunicamycin
4. All of these

✅ Correct Answer: 1

Replication in E. coli is initiated by the generation of short RNA primers using

1. RNA polymerase
2. primase
3. reverse transcriptase
4. both (a) and (b)

✅ Correct Answer: 4

DNA replication results in

1. two completely new DNA molecules
2. two DNA molecules such that each one contains a strand of the original
3. one new DNA molecules 1 old molecule
4. one new molecule of RNA

✅ Correct Answer: 2

Which enzyme catalyzes the elongation of DNA molecules?

1. DNA polymerase
2. Helicase
3. DNA ligase
4. Primase

✅ Correct Answer: 1

What is the IUPAC code for an A, C, T ambiguity in a nucleic acid sequence?

1. B
2. H
3. S
4. None of these

✅ Correct Answer: 2

There is a single origin for DNA replication in bacteria. How many origins of replication are found in the much larger genomes of eukaryotes such as mammals?

1. One
2. About 100
3. Thousands and tens of thousands
4. none of these

✅ Correct Answer: 3

Automated DNA sequencing uses the chain termination method

1. but with an oligonucleotide primer labeled with a fluorescent dye
2. but with a polynucleotide primer labeled with a fluorescent dye
3. with no primer
4. either (b) or c

✅ Correct Answer: 1

Okazaki fragments occur on the __________ and are bonded together by _________

1. Leading strand, polymerase
2. mRNA, anticodons
3. Lagging strand, ligase
4. tRNA, polymerase

✅ Correct Answer: 3

The RNA primers used to initiate replication in E. coli

1. result in Okazaki fragments on leading strand
2. are removed by Pol I
3. are joined together by DNA ligase
4. are removed by helicase + ATP

✅ Correct Answer: 2

An enzyme that recognizes foreign DNA, and results in a cut in that DNA is called

1. transposase
2. helicase
3. reverse transcriptase
4. restriction endonuclease5

✅ Correct Answer: 4

Which of the following is an active site on its single polypeptide chain for DNA Polymerase I?

1. 5' → 3' polymerase
2. 3' → 5' exonuclease
3. 5' → 3' exonuclease
4. all of the above

✅ Correct Answer: 1

Which of the following is not a structural motif in DNA binding proteins?

1. bZIP
2. helix-turn-helix
3. TFIID
4. . zinc finger

✅ Correct Answer: 3

DNA with a G-C content of 50% will melt at approximately

1. 60°C
2. 70°C
3. 90°C
4. 100°C

✅ Correct Answer: 3

Who's X-ray work aided Watson and Crick in their discovery of the double helix?

1. W.H. Bragg
2. R. Franklin
3. L. Pauling
4. Leaderberg

✅ Correct Answer: 2

DNA replication in eukaryotes occurs only in

1. G1 phase
2. S phase
3. G2 phase
4. M phase

✅ Correct Answer: 2

Which polymerase is active in DNA repairing

1. Polymerase I
2. Polymerase II
3. Polymerase III
4. none of these

✅ Correct Answer: 2

For the DNA replication in eukaryotes, the cell cycle consists of

1. G1, G2 and M phases
2. S, G2 and M phases
3. G1,S, G2 and M phases
4. G2 and M phases

✅ Correct Answer: 3

Which of the following in DNA replication and transcription are common?

1. incorporation of deoxynucleotides
2. utilization the same enzyme
3. synthesis in the 5'-3' direction
4. none of the above

✅ Correct Answer: 3

An important difference between eukaryotic and prokaryotic DNA replication is

1. eukaryotic DNA polymerases are faster
2. more DNA polymerases are found in eukaryotes
3. multiple origins of replication in eukaryotes
4. RNA primers are not required in eukaryotes

✅ Correct Answer: 3

In DNA, nucleotides are covalently joined together by

1. 3', 5' phosphodiester bonds to form a repetitive sugar-phosphate chain
2. 2', 5' phosphodiester bonds to form a repetitive sugar-phosphate chain
3. 2', 3' phosphodiester bonds to form a repetitive sugar-phosphate chain
4. 3', 4' phosphodiester bonds to form a repetitive sugar-phosphate chain

✅ Correct Answer: 1

What is the name given to the points at which a DNA helix is unwound and new strands develop?

1. Replication origins
2. Replication forks
3. Leading strands
4. Okazaki fragments

✅ Correct Answer: 2

The DNA is negatively super coiled, complexes to histone,

1. HU
2. HSP-1
3. H-NS
4. All of these

✅ Correct Answer: 4

During conventional transformation experiments E. coli cells and plasmid DNA interacts in an environment of

1. high temperature and Ca++
2. low temperature and Ca++
3. high temperature and Mg++
4. low temperature and Mg++

✅ Correct Answer: 2

What is the exact name of the classical Watson-Crick double helix DNA?

1. A-DNA
2. B-DNA
3. Z-DNA
4. X-DNA

✅ Correct Answer: 2

The site on a bacterial chromosome that marks the initiation point for chromosome replication is called

1. Ori
2. a promoter
3. Pro
4. an initiation codon

✅ Correct Answer: 1

The B-DNA structure found in solution is a

1. left-handed double helix of antiparallel chains (10 bp/turn)
2. right-handed double helix of antiparallel chains (∼10 bp/turn)
3. left-handed zig-zag helix of antiparallel chains (10 bp/turn)
4. right-handed double helix of parallel chains (∼10 bp/turn)

✅ Correct Answer: 2

Which will require a higher temperature to denature?

1. DNA with a high G-C content
2. DNA with a high A-T content
3. RNA with a high G-C content
4. RNA with a high A-T content

✅ Correct Answer: 1

In an agarose gel, DNA is moving from

1. cathode to anode
2. left to right
3. anode to cathode
4. A to B

✅ Correct Answer: 1

TM refers to the temperature at which

1. membranes are 50% fluid
2. 50% of a DNA molecule is denatured
3. 50% of a protein molecules are denatured
4. all of the above

✅ Correct Answer: 4

DNA segments capable of moving from one place in the genome to another is known as

1. transposons
2. retrovirus
3. introns
4. moving elements

✅ Correct Answer: 1

What does ligase do during replication of DNA?

1. Synthesizes the lagging strand
2. Makes copies of mRNA from DNA
3. Joins nicks in DNA strands
4. Digests mRNA when it is no longer needed

✅ Correct Answer: 3

Proteins which help to open the double helix for DNA synthesis are

1. DNA helicases
2. single stranded binding proteins
3. ligase
4. DNA topoisomerase

✅ Correct Answer: 1

First evident that DNA is genetic material comes from the experiment of Griffith is

1. transduction
2. transformation
3. replication
4. translation

✅ Correct Answer: 2

An RNA primer is synthesized by

1. DNA helicases
2. ligase
3. DNA topoisomerase
4. primase

✅ Correct Answer: 4

Which of these restriction enzymes produce blunt ends?

1. SaII
2. EcoRV
3. XhoI
4. HindIII

✅ Correct Answer: 2

The RP13 gene of chromosome 17 codes for a protein __________ .

1. involved in glucose transport
2. that is a component of hair and nails
3. involved in eye development
4. involved in the determination of personality

✅ Correct Answer: 3

Isoschizomers recognize

1. same recognition sequence but different recognition site
2. same recognition site and recognition sequence
3. same recognition site and different recognition sequence
4. different recognition site and different recognition sequence

✅ Correct Answer: 2

Restriction enzymes are named for

1. the person who discovered
2. the bacterium they are derived from
3. the viral DNA that they attack
4. none of the above

✅ Correct Answer: 2

Which of these genes codes for a protein that plays a role in white blood cell function?

1. DCP1
2. MPO
3. GLUT4
4. RP13

✅ Correct Answer: 2

When populations are small, gene frequencies can change from generation to generation and some alleles may become fixed in a population. This is called __________ .

1. assortative mating
2. inbreeding
3. heterosis
4. genetic drift

✅ Correct Answer: 4

Which of the following is correct in terms of determination of location of genetic traits?

1. Known protein coding sequences are too far apart to allow linkage determination for most new genes
2. Restriction sites allow DNAs to be digested
3. Protein-coding genes are always associated with a restriction pattern
4. None of the above

✅ Correct Answer: 1

n gel electrophoresis, DNA molecules migrate from __________ to __________ ends of the gel.

1. negative ... positive
2. basic ... acidic
3. long ... short
4. positive to negative

✅ Correct Answer: 1

Restriction enzymes

1. protect bacteria from viral infection
2. cut DNA in a staggered fashion
3. cut DNAs producing a blunt end
4. all of the above

✅ Correct Answer: 4

First discovered, Type II restriction endonuclease was

1. Hinf I
2. Eco K
3. Hind II
4. EcoRI

✅ Correct Answer: 3

Which of the following techniques can be used to determine the defective gene and for developing cancer?

1. Western blot
2. Southern blot
3. Northern blot
4. Eastern blot

✅ Correct Answer: 2

The transfer of antibiotic-resistant genes from genetically engineered bacteria to disease-causing bacteria __________ .

1. would be of no concern if it occurred.
2. has occurred
3. can never occur
4. seems unlikely

✅ Correct Answer: 4

Both DNA gel electrophoresis and SDS-PAGE of proteins are similar because

1. in both cases molecules migrate to the anode
2. both techniques rely on a constant charge to mass ratio
3. both techniques utilize the sieving properties of gels
4. all of the above

✅ Correct Answer: 4

Some genetic diseases cannot be diagnosed by changes in restriction sites. Some of these can be detected by allele-specific oligonucleotide probes. These are

1. copies of the gene with an altered sequence so that a restriction site is inserted
2. mutagenized copies of a gene
3. short sequences that will hybridize only to a specific base sequence
4. PCR-amplified variable numbers of tandem repeats (VNTRs)

✅ Correct Answer: 3

In order to insert a foreign gene into a plasmid, both must __________

1. have identical DNA sequences
2. originate from the same type of cell
3. be cut by the same restriction enzyme
4. be of the same length

✅ Correct Answer: 3

Which of the following genetic diseases would be amenable to genetic engineering?

1. Down's syndrome
2. Muscular dystrophy
3. Cystic fibrosis
4. Cri du Chat

✅ Correct Answer: 3

X-rays cause

1. the formation of thymine dimers
2. ionization of water in the cell
3. heat
4. none of the above

✅ Correct Answer: 2

The order for the construction of a cDNA fragment from mRNA is to

1. bind oligo-dT, treat with reverse transcriptase, digest with RNase, add G residues to the 3' end, bind oligo-dC, treat with DNA polymerase
2. treat with reverse transcriptase, digest with RNase, add G residues to the 3' end, bind oligo-dC, treat with DNA polymerase and bind oligo-dT
3. digest with RNase, add G residues to the 3' end, treat with reverse transcriptase, add G residues to the 3' end and treat with DNA polymerase
4. bind oligo-dC, treat with reverse transcriptase, digest with RNase, add G residues to the 3' end, bind oligo-dT and treat with DNA polymerase

✅ Correct Answer: 1

The TP53 gene of chromosome 17 codes for a protein __________ .

1. that plays a role in the digestive process
2. involved in glucose transport
3. involved in the regulation of the cell cycle
4. that is like a white blood cell protein

✅ Correct Answer: 3

Why is golden rice pale yellow in color?

1. It is rich in chlorophyll a.
2. It is rich in beta-carotene.
3. It is rich in chlorophyll b.
4. It is rich in phycobilins.

✅ Correct Answer: 2

Which type of restriction enzymes do not usually require ATP?

1. Type I
2. Type II
3. Type III
4. Type IV

✅ Correct Answer: 2

An example of a restriction fragment length polymorphism is

1. an Eco RI cuts DNA at a different sequence than Hind III
2. different length fragments of DNA resulting from loss or gain of a restriction site
3. cystic fibrosis results from a three base deletion in most cases but in other cases, other mutations are involved
4. all of the above

✅ Correct Answer: 2

Knockout mice are created by

1. mutagenizing a mouse and selecting for mutant offspring
2. creating a chimera by fusing cells from two different cell lines
3. infecting the mouse with a retrovirus
4. transfecting embryonic stem cells with an altered gene sequence

✅ Correct Answer: 4

A plasmid

1. is a circular DNA molecule
2. always contains an origin of replication
3. usually contains one or more restriction sites
4. all of the above

✅ Correct Answer: 4

Under which of the following conditions would population gene frequencies remain the same?

1. Selection for homozygotes
2. Small population size
3. Active migration between groups
4. Random mating

✅ Correct Answer: 4

Plant transformation can be obtained by

1. combining plant and animal cells in culture
2. shooting DNA into plant cells with a gun
3. using the E. coli bacterium to infect plant roots
4. infecting plants with a tobacco mosaic virus

✅ Correct Answer: 2

An expression vector

1. always contains an origin of replication
2. usually contains a gene that confers antibiotic resistance to the bacterial host
3. always contains DNA segments for the regulation of mRNA production
4. all of the above

✅ Correct Answer: 4

he unpaired nucleotides produced by the action of restriction enzymes are referred to have

1. sticky ends
2. single strands
3. restriction fragments
4. ligases

✅ Correct Answer: 1

Which of the following is not true of small inbreeding populations?

1. They tend to loose genetic diversity
2. There is an increased incidence of recessive diseases
3. Alleles may become fixed
4. Mutation is increased

✅ Correct Answer: 4

Which of these genes codes for a protein that plays a role in growth?

1. DCP1
2. SCLC6A4
3. KRTHA1
4. GH1

✅ Correct Answer: 4

Which of the following pair will produce complementary sticky ends?

1. Eco RI & MspI
2. Msp I & HPA II
3. Sau 3A & Bam HI
4. Mbo I & Sau 3A

✅ Correct Answer: 3

A human cDNA library

1. contains DNA for specific human proteins
2. contains DNA for virtually all of the human proteins in vectors
3. cannot be used to obtain human genes because it would be radioactive
4. none of the above

✅ Correct Answer: 2

What enzyme forms covalent bonds between restriction fragments?.

1. DNA primase
2. DNA helicase
3. DNA polymerase
4. DNA ligase

✅ Correct Answer: 4