Translation begins
1.at the replication fork
2.on the lagging strand
3.at the start codon
4. in nucleus
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
In membranes, lipids are
1.glycerophospholipids
2.sphingolipids
3.sterols
4.all of these
In prokaryotes, AUG encodes
1.methionine
2.N-formyl methionine
3. a stop codon
4.alanine
Which of the following is found on RNA but not DNA?
1.Uracil
2.Deoxyribose
3.Phosphate
4.Adenine
A five carbon sugar lacking a hydrogen at the number 2 carbon is found in
1.DNA
2.RNA
3.mRNA
4.rDNA
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
A purine with an amine (NH2) group on the 6th carbon is
1.adenine
2.cytosine
3.thymine
4.guanine
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
AUG codes for methionine act as a
1.initiation code
2.elongation code
3.termination code
4.propagation code
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
Bacteriorhodopsin
1.absorbs light and pumps protons
2.is an integral membrane protein
3.contains primarily alpha-helical residues
4.all of the above
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
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
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
Codon that specify the amino acids often differs in the
1.first base
2.second base
3. third base
4. none of these
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
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
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
How many amino acids will be encoded by 5' GAU GGU UGA UGU 3' sequence?
1.One
2.Two
3.Three
4.Four
How many different codons are possible?
1.3
2.20
3.64
4.An infinite number
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
In active transport, the membrane structure that functions is
1.cholesterol
2. integral proteins
3.carbohydrates
4.hydrophobic molecules
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
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
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
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
Lysozymes are found in
1.plant cells
2.animal cells
3. microbial cells
4.all of these
Membrane lipids are
1.hydrophilic
2.hydrophobic
3.ampiphillic
4.none of these
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
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
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
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
Peptidoglycan is a complex consisting of
1. oligo-saccharide and protein
2.polysaccharide and protein
3. mono-saccharide and protein
4.aminoacid and carbohydrate
Pinocytosis occurs in
1.all eukaryotic cells
2.all prokaryotic cells
3.mitochondria of all cells
4.none of these
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
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
RNA polymerase in prokaryotes has a removable
1.alpha subunit
2.beta subunit
3.both (a) and (b)
4. sigma subunit
Rocket Immunodiffusion is also known as
1.gel diffusion
2.electroimmunodiffusion
3.double-diffusion
4.none of these
The codons which do not specify an amino acid are called
1.initiation code
2. termination code
3.propagation code
4.none of these
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
The genetic code is
1.universal
2. universal except for rare exceptions in mitochondria and some protozoa
3.species-specific
4.kingdom-specific
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
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°
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
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
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
The most stabilizing force for nucleic acids is
1.hydrogen bonds
2.electrostatic bond
3.Van der Waals
4.conformational entropy
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
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
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'
The smooth endoplasmic reticulum (SER) is the site of
1. phospholipid synthesis
2.amino acid synthesis
3. carbohydrate synthesis
4.protein synthesis
The sugar in RNA is __________ , the sugar in DNA is __________
1.deoxyribose, ribose
2.ribose, deoxyribose
3. ribose, phosphate
4.ribose, uracil
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
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
What is approximatively the half life of 32-Phosphorus?
1.14 days
2.28 days
3.42 days
4.30 days
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
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
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
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
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
Which of the following is a purine?
1.Cytosine
2.Adenine
3.Thymine
4.Uracil
Which of the following is an immunoelectrophoresis technique?
1.immunoelectrophoresis
2.Counterimmunoelectrophoresis
3.Coimmunoelectrophoresis
4.Both (a) and (b)
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
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
Which of the following is not found in membranes?
1.Glycoproteins
2.Glycolipids
3.Nucleic acids
4.Phospholipids
Which of the following radioactive element is generally involved in RIA?
1.Tritium
2.Carbon-14
3. Iodine-125
4. All of these
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
Which pyrimidine base contains an amino group at carbon 4?
1.Cytosine
2.Thymine
3.Uracil
4.Adenine
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