R4RIN – MCQs, Mock Tests | Biochemistry Biochemistry MCQS PAPER SET 1

Agarose a porous matrix used in various molecular biology technique is made by repetitive units of

1. maltose
2. agarobiose
3. agar
4. none of these

✅ Correct Answer: 1

What radioactive molecule is used to end-label an oligonucleotide?

1. (alpha)-32P-ATP
2. (alpha)-32P-dUTP
3. (gamma)-32P-ATP
4. Any of these

✅ Correct Answer: 3

Which of the following radioactive element is generally involved in RIA?

1. Tritium
2. Carbon-14
3. Iodine-125
4. All of these

✅ Correct Answer: 4

What is approximatively the half life of 32-Phosphorus?

1. 14 days
2. 28 days
3. 42 days
4. 30 days

✅ Correct Answer: 1

Rocket Immunodiffusion is also known as

1. gel diffusion
2. electroimmunodiffusion
3. double-diffusion
4. none of these

✅ Correct Answer: 2

DNA- footprinting is a suitable technique for identifying which of the following?

1. Particular mRNA in mixture
2. Particular t-RNA in mixture
3. Introns within DNA
4. Protein binding site within DNA

✅ Correct Answer: 4

What would happen if serum is omitted from the ELISA, but all other steps remain same?

1. Anti-human Ig-conjugate would not bind and be washed away
2. The OD values would be nearly the same as the assay control
3. Both (a) and (b)
4. Anti-human Ig-conjugate would bind non-specifically to the ELISA plate

✅ Correct Answer: 3

RAST test (radio allergosorbent test) is often used to detect

1. antibodies associated with allergies (IgE)
2. antigen associated with allergies (IgE)
3. bacteriophages
4. . None of the above

✅ Correct Answer: 1

What would happen if the anti-human Ig-conjugate is not washed free of the well before the substrate is added?

1. The ELISA would not develop when the substrate was added
2. The ELISA would develop normally
3. All wells would show uniform over-development due to unbound and excess anti-human Ig enzyme conjugate
4. None of the above

✅ Correct Answer: 3

An antigen preparation and an antibody preparation are tested by immunodiffusion. Three bands are found, indicating that

1. there was more than one antigen
2. the antibody was impure
3. the temperature was too high
4. there was one antibody and one antigen

✅ Correct Answer: 1

Immunoelectrophoresis techniques are designed to separate the mixture components from each other by using electrophoresis

1. prior to reaction with antibody
2. prior to reaction with antigen
3. after reaction with antibody
4. after reaction with antigen

✅ Correct Answer: 1

Which of the following is a positively charged matrix for ion exchange chromatography?

1. CM cellulose
2. DEAE cellulose
3. Phosphocellulose
4. None of these

✅ Correct Answer: 2

Which of the following is an immunoelectrophoresis technique?

1. immunoelectrophoresis
2. Counterimmunoelectrophoresis
3. Coimmunoelectrophoresis
4. Both (a) and (b)

✅ Correct Answer: 4

Cholesterol is somewhat amphipathic due to

1. the single hydroxyl along with the hydrocarbon nature of the remainder of the molecule
2. . the long branched hydrocarbon along with the four hydrocarbon rings
3. the five-methyl groups along with the hydrocarbon chain
4. the three six-membered rings along with the single five-membered ring

✅ Correct Answer: 1

Bacteriorhodopsin

1. absorbs light and pumps protons
2. is an integral membrane protein
3. contains primarily alpha-helical residues
4. all of the above

✅ Correct Answer: 4

In active transport, the membrane structure that functions is

1. cholesterol
2. integral proteins
3. carbohydrates
4. hydrophobic molecules

✅ Correct Answer: 2

Cholesterol is essential for normal membrane functions because it

1. plugs up the cardiac arteries of older men
2. cannot be made by higher organisms
3. keeps membranes fluid.
4. spans the thickness of the bilayer

✅ Correct Answer: 3

The model that is now known to be correct for the structure of biological membrane is

1. Fluid mosaic model
2. Page's model
3. Lac Operon model
4. Lock and Key model

✅ Correct Answer: 1

n Fluid mosaic model, the biological membrane can be viewed as

1. two dimensional solutions of oriented lipids and globular proteins
2. three dimensional solutions of oriented lipids and globular proteins
3. two dimensional solutions of oriented lipids and carbohydrate
4. three dimensional solutions of oriented lipids and carbohydrate

✅ Correct Answer: 1

Membrane lipids are

1. hydrophilic
2. hydrophobic
3. ampiphillic
4. none of these

✅ Correct Answer: 1

Pinocytosis occurs in

1. all eukaryotic cells
2. all prokaryotic cells
3. mitochondria of all cells
4. none of these

✅ Correct Answer: 1

Exocytosis is the secretion of proteins

1. out of the cell across the plasma membrane into the extracellular space
2. out of the cell across the plasma membrane into the intracellular space
3. is the uptake of macromolecules from the extracellular space into the cell across the plasma membrane
4. is the uptake of macromolecules from the intracellular space into the cell across the plasma membrane

✅ Correct Answer: 1

The membrane proteins that catalyze active transport reactions differ from soluble enzymes as

1. they are permanently changed during the reaction
2. the substrates of the reaction are all outside the cell
3. they do not enhance the rates of reaction
4. the products of the reaction move in a specific direction

✅ Correct Answer: 4

The movement of molecules across a membrane by passive transport does not require

1. an input of metabolic energy
2. internal energy
3. vibrational energy
4. none of these

✅ Correct Answer: 1

Peptidoglycan is a complex consisting of

1. oligo-saccharide and protein
2. polysaccharide and protein
3. mono-saccharide and protein
4. aminoacid and carbohydrate

✅ Correct Answer: 1

The mesosomes may be the sites of

1. DNA replication and specialized enzymatic reactions
2. RNA replications and specialized enzymatic reactions
3. RNA replications and specialized cyclic reactions
4. None of the above

✅ Correct Answer: 1

Which of the following is correct?

1. Peroxisomes have a single boundary membrane
2. Peroxisomes contain enzymes that degrade fatty acids and amino acids
3. The byproduct of given reactions in (b) is toxic to cells
4. All of the above

✅ Correct Answer: 4

The smooth endoplasmic reticulum (SER) is the site of

1. phospholipid synthesis
2. amino acid synthesis
3. carbohydrate synthesis
4. protein synthesis

✅ Correct Answer: 1

Lysozymes are found in

1. plant cells
2. animal cells
3. microbial cells
4. all of these

✅ Correct Answer: 2

Biological membranes are like water beds because

1. they are always moving
2. they (normally) do not leak their contents
3. the membrane is thin compared to the enclosed volume
4. all of the above

✅ Correct Answer: 4

The plasma membrane is a selectively permeable barrier due to presence of specific transport

1. proteins
2. amino acids
3. carbohydrates
4. none of these

✅ Correct Answer: 1

Which type of molecule spans the membrane, from its inner to outer surface according to the Fluid mosaic model of cell membranes?

1. Cholesterol
2. Phospholipid
3. Protein
4. Carbohydrate

✅ Correct Answer: 3

Which of the following is correct?

1. Membranes form boundaries around the cell and distinct subcellular components
2. Membranes act as selectively permeable barrier
3. Membranes contain varying amount of lipid and protein and some contain small amount of carbohydrates
4. All of the above

✅ Correct Answer: 4

In membranes, lipids are

1. glycerophospholipids
2. sphingolipids
3. sterols
4. all of these

✅ Correct Answer: 4

Which of the following is not found in membranes?

1. Glycoproteins
2. Glycolipids
3. Nucleic acids
4. Phospholipids

✅ Correct Answer: 3

Because DNA is a highly charged polyanion, its stability to heat denaturation

1. does not depend on hydrophobic interactions
2. increases with increasing salt
3. is independent of G - C content
4. decreases with increasing salt

✅ Correct Answer: 2

The sugar in RNA is __________ , the sugar in DNA is __________

1. deoxyribose, ribose
2. ribose, deoxyribose
3. ribose, phosphate
4. ribose, uracil

✅ Correct Answer: 2

Nucleoside is a pyrimidine or purine base

1. covalently bonded to a sugar
2. ionically bonded to a sugar
3. hydrogen bonded to a sugar
4. none of the above

✅ Correct Answer: 1

In gel electrophoresis, what fragments will move most quickly through a gel?

1. Large fragments
2. Small fragments
3. Large genome
4. None of these

✅ Correct Answer: 2

Which pyrimidine base contains an amino group at carbon 4?

1. Cytosine
2. Thymine
3. Uracil
4. Adenine

✅ Correct Answer: 1

Nucleotide bases and aromatic amino acids absorb light respectively at

1. 280 and 260 nm
2. 260 and 280 nm
3. 270 and 280 nm
4. 260 and 270 nm

✅ Correct Answer: 2

The glycosidic bonds in DNA and RNA

1. connect the sugar to the base
2. can be hydrolyzed by OH- ion
3. stabilize Watson-Crick H-bonds
4. are free to rotate over about 180°

✅ Correct Answer: 1

Nucleic acids can be analyzed experimentally by their

1. molecular weight
2. absorption of visible light
3. absorption of uv light
4. none of these

✅ Correct Answer: 3

Thymidine

1. can participate in hydrophobic interactions due to its methyl group
2. is replaced by uracil in RNA
3. normally forms two hydrogen bonds with adenosine
4. all of the above

✅ Correct Answer: 4

A nucleotide consists of

1. a sugar, a base and a phosphate
2. a sugar and a phosphate
3. paired bases
4. a sugar, a base and three phosphates

✅ Correct Answer: 1

A five carbon sugar lacking a hydrogen at the number 2 carbon is found in

1. DNA
2. RNA
3. mRNA
4. rDNA

✅ Correct Answer: 1

The unfavourable free energy associated with not satisfying a hydrogen bond after formation of the double helix is approximately

1. 10 kJ/mol
2. 20 kJ/mol
3. 25 kJ/mol
4. 30 kJ/mol

✅ Correct Answer: 2

The most stabilizing force for nucleic acids is

1. hydrogen bonds
2. electrostatic bond
3. Van der Waals
4. conformational entropy

✅ Correct Answer: 3

A purine with an amine (NH2) group on the 6th carbon is

1. adenine
2. cytosine
3. thymine
4. guanine

✅ Correct Answer: 1

Which of the following is found on RNA but not DNA?

1. Uracil
2. Deoxyribose
3. Phosphate
4. Adenine

✅ Correct Answer: 1

Which of the following is a purine?

1. Cytosine
2. Adenine
3. Thymine
4. Uracil

✅ Correct Answer: 2

Which of the following techniques was carried out by Nirenberg and Matthaei in 1961 to determine the first codon?

1. In vitro synthesis of a polypeptide using UUUUU
2. Labeled peptide binding to a ribosome
3. Mixed co-polymer mRNA synthesis
4. none of the above

✅ Correct Answer: 1

Bacterial protein called catabolic activator protein (CAP) is an example of

1. negative control of gene expression
2. positive control of gene expression
3. second type of positive control of gene expression
4. none of the above

✅ Correct Answer: 3

How many different codons are possible?

1. 3
2. 20
3. 64
4. An infinite number

✅ Correct Answer: 3

The genetic code is

1. universal
2. universal except for rare exceptions in mitochondria and some protozoa
3. species-specific
4. kingdom-specific

✅ Correct Answer: 2

Which of the following has been used as an evidence that primitive life forms lacked both DNA and enzymes?

1. RNA can both code genetic information and act as a catalyst
2. DNA and enzymes are only present in the most advanced cells
3. Advanced cells lack RNA
4. All of the above

✅ Correct Answer: 1

Crick demonstrated that the genetic code involved three bases and suggested that the code was degenerated. What experimental technique Crick conducted to suggest genetic code degeneration?

1. Gel electrophoresis
2. Density gradient centrifugation
3. Frameshift mutagenesis
4. Restriction digests of the rII gene

✅ Correct Answer: 3

Codon that specify the amino acids often differs in the

1. first base
2. second base
3. third base
4. none of these

✅ Correct Answer: 3

In some organelles in eukaryotes, the genetic code for some codons

1. differs from that used in prokaryotes
2. are same
3. are partially same
4. none of the above

✅ Correct Answer: 1

The codons which do not specify an amino acid are called

1. initiation code
2. termination code
3. propagation code
4. none of these

✅ Correct Answer: 2

The genetic code is degenerated. Which of the following codons represents the principle of degeneracy?

1. UAA and UAC
2. AUG and AUA
3. CAU and CAC
4. UUA and UUC

✅ Correct Answer: 3

The sequence of one strand of DNA is: 5' ATTGCCA 3', what is the sequence of the other strand?

1. 5' TAACGGT 3'
2. 5' TGGCAAT 3'
3. 5' ATTGCCA 3'
4. . 5' UAAGCCU3'

✅ Correct Answer: 2

In prokaryotes, AUG encodes

1. methionine
2. N-formyl methionine
3. a stop codon
4. alanine

✅ Correct Answer: 2

How many amino acids will be encoded by 5' GAU GGU UGA UGU 3' sequence?

1. One
2. Two
3. Three
4. Four

✅ Correct Answer: 2

In protein synthesis in prokaryotes

1. the initiating amino acid is N- formyl methionine
2. the initiating amino acid is methionine
3. the initiating amino acid is phenyl alanine
4. none of the above

✅ Correct Answer: 1

AUG codes for methionine act as a

1. initiation code
2. elongation code
3. termination code
4. propagation code

✅ Correct Answer: 1

Translation begins

1. at the replication fork
2. on the lagging strand
3. at the start codon
4. in nucleus

✅ Correct Answer: 3

The complex of RNA polymerase, DNA template and new RNA transcript is called

1. transcription bubble
2. replication bubble
3. a translation bubble
4. none of these

✅ Correct Answer: 1

RNA polymerase in prokaryotes has a removable

1. alpha subunit
2. beta subunit
3. both (a) and (b)
4. sigma subunit

✅ Correct Answer: 4

Promoters for tRNAs are located

1. upstream from the start codon
2. downstream from the start codon
3. both (a) and (b)
4. none of these

✅ Correct Answer: 2