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Right CHOICE is (c) polymerase

Easy explanation: Taq polymerase, derived from the thermophilic BACTERIA Thermus aquaticus is active at 72°. The enzyme is responsible for synthesizing the complementary DNA strand by ADDING NUCLEOTIDES to the 3’ end of the primers.

The CORRECT answer is (b) isopycnic

The explanation: Equilibrium centrifugation (also termed isopycnic centrifugation) SEPARATES the nucleic acid molecules based on their buoyant density. The gradient is ESTABLISHED by using CESIUM chloride or cesium sulfate.

Correct option is (a) Tandem MS

To elaborate: Tandem MS (also termed MS/MS) is a two-step procedure that gives AMINO acid SEQUENCE of a polypeptide and hence a COMPLETE unmistakable identification of an UNIDENTIFIED protein.

The correct option is (C) m/z ratio

The best explanation: In MASS SPECTROMETRY, proteins get separated based on their mass-to-charge (m/z) ratios. Smaller ions travel faster and STRIKE the detector while the larger, heavier ions move slower.

The correct choice is (a) True

Easiest EXPLANATION: ISOELECTRIC point is the PH value at which the negative charges and the positive charges are equal in a PROTEIN, and the protein is neutral. Usually, the isoelectric point of proteins is below 7.

Correct option is (c) HEAVY metal soutions

The explanation is: The tissue is stained by floating on drops of uranyl acetate and LEAD citrate (heavy metal solutions). These solutions when bound to the specimen, PROVIDE the density required to scatter the electron BEAM.

The CORRECT option is (a) tungsten wire

The explanation is: The cathode of a transmission ELECTRON microscope (TEM) is located on top of the COLUMN, it contains a tungsten wire filament that is heated to provide the source of electrons.

The correct OPTION is (a) toluene

Best EXPLANATION: After fixation the tissue is dehydrated (USING ALCOHOLS) and embedded in paraffin wax for mechanical support during SECTIONING. Slides containing adherent paraffin wax are immersed in the toluene which dissolves the wax.

Right CHOICE is (d) sucrose

The best I can explain: For polyacrylamide gel electrophoresis (PAGE), the PROTEIN samples are PREPARED in a solution of sucrose or glycerol to PROVIDE density. This prevents the mixing of protein samples with the running buffer.

Right answer is (d) number of protons

Easiest EXPLANATION: The identity and CHEMICAL PROPERTIES of a compound can be DETERMINED by the number of POSITIVELY charged protons it contains. For example, hydrogen has a single proton and helium has two.

The correct ANSWER is (a) True

The best I can explain: For sample preparation of SEM, the BASIC requirement is PRODUCING specimen that has the same shape and surface properties as that of the living cell and at the same TIME is devoid of any fluid for viewing under the vacuum.

Correct ANSWER is (B) DNA can be TAKEN up from medium

To explain: According to the experiments performed by Avery, Macleod, and McCarty; it came to be known that BACTERIAL cells can take up the DNA present in the medium. This FORMED the basis of cloning plasmids in the bacterial cells.

The correct choice is (b) cellulose

Easiest explanation: Ion-exchange CHROMATOGRAPHY uses ionic bonding of proteins to an INERT matrix MATERIAL such as cellulose. Two types of cellulose RESINS commonly used are diethyl-aminoethyl (DEAE) cellulose and carboxymethyl (CM) cellulose.

Right answer is (B) Cell-free systems

Best explanation: Organelles that are isolated from the CELLS can be SUSPENDED into a medium that mimics the in-vivo CONDITIONS of the cell. This is known as a cell free system. This can be used to study interactions between organelles.

Correct option is (d) CALCIUM

Easy explanation: EDTA (ethylenediamine tetracetate) is a chelating AGENT that binds to calcium ions and prevents CELLULAR adhesion. A chelating agent REACTS with metal ions to form a water-soluble complex.

Correct CHOICE is (d) 50X

The explanation is: The more the MAGNIFICATION of the ocular, the more retinal SURFACE it covers. However, beyond a CERTAIN magnification, the image is not clear (termed empty magnification) EVEN if it occupies a greater retinal surface.

The correct option is (a) nucleotide length

Easiest explanation: In rate-zonal sedimentation (ALSO TERMED velocity-sedimentation), the nucleic acids (deoxyribonucleic acids and ribonucleic acids) are SEPARATED based on the lengths of their nucleotide SEQUENCE.

Correct ANSWER is (c) in solution

The best explanation: Electrospray IONIZATION is an alternate procedure to Matrix-assisted laser desorption ionization, which is WELL suited for proteins in solution (the ONES fractionated using LIQUID chromatography).

Correct option is (C) affinity chromatography

Best explanation: The proteins participating in interactions such as ligand-ligand, enzyme-substrate etc. can be PURIFIED using the affinity chromatography. In this technique, an interacting molecule is covalently attached to the INERT MATRIX.

Right answer is (d) effective SIZE

To explain: Gel-filtration chromatography separates the proteins BASED on their effective size (hydrodynamic radius). The COLUMN material consists of cross-linked polysaccharides like AGAROSE and dextrans.

Right choice is (b) False

The best EXPLANATION: Both Transmission Electron Microscope (TEM) and Scanning Electron Microscope (SEM) use electrons to GENERATE images but they differ by the mode of image generation. TEM uses electrons that pass through the sample WHEREAS SEM uses electrons that are REFLECTED or knocked off from the sample.

Right answer is (a) oil immersion

Easy explanation: For a LENS to be used in oil immersion, the maximum possible NUMERICAL APERTURE is 1.5. The maximum useful magnification of a microscope is 500 to 1000 TIMES that of the numerical aperture of the objective lens being used.

The correct option is (a) True

To explain: The NUMERICAL aperture is the measure of light gathering capacity of a lens. It is constant for each lens and is represented by the following equation – n*SIN*α. The refractive index of medium PRESENT is denoted by ‘n’.

Correct choice is (a) callus culture

For EXPLANATION I would say: Under favorable CONDITIONS and CHEMICALLY defined media, the PROTOPLASTS can grow into an undifferentiated cell mass, known as the callus culture. Protoplasts are the cells whose plasma membranes have been removed.

The correct answer is (a) isolated PARTICLES

The best I can EXPLAIN: SHADOW casting is a technique of viewing isolated particles. The particles are made to CAST shadows after their placement in sealed chambers. The CHAMBER contains a filament of carbon and a heavy metal.

Right choice is (c) tri-nucleotide

Easy EXPLANATION: The endonuclease HaeIII and Sau3A, are tetranucleotide sequences USED in the CONSTRUCTION of GENOMIC DNA libraries. After digestion of the nucleotides, the fragments are SEPARATED by gel electrophoresis.

The correct answer is (c) oligonucleotides

The explanation: MOLECULAR BEACONS are SHORT REPORTER oligonucleotides that have a fluorochrome and a quencher molecule attached to opposite ends. The molecular beacons hybridize in the MIDDLE of the sequence to be amplified.

The CORRECT answer is (a) 95°, 60°, 72°

Easiest explanation: Three different TEMPERATURES are reached during the polymerase CHAIN REACTION to facilitate the denaturation and hybridization of the DNA strands. First the temperature is elevated to 95°C, then lowered to 60°C and then again increased to 72°C.

Correct answer is (a) True

For explanation: BACTERIOPHAGES are viruses that infect bacterial cells. BACTERIOPHAGE lambda genome is linear and double-stranded and of the size of 50 kb in length.it is an IMPORTANT cloning vector.

Correct choice is (a) ligase

Best explanation: DNA ligase is used to join two DIFFERENT types of DNA molecules, thus giving rise to a RECOMBINANT molecule that can be CLONED inside a suitable HOST to facilitate the gene expression.

The correct option is (b) Isopycnic centrifugation

Easy explanation: Isopycnic or equilibrium centrifugation can be used to separate nucleic ACIDS having different base COMPOSITION and EVEN different isotopes of NITROGEN such as ^15N and ^14N.

The correct answer is (a) True

For explanation I would say: Charge DENSITY is the charge per unit MASS of the protein MOLECULE. The RATE of movement of a protein through the gel matrix depends on its charge density, the more the charge density, the faster the protein will reach the electrode.

Correct option is (c) differential CENTRIFUGATION

The explanation is: For studying a particular ORGANELLE, it is first IMPORTANT to isolate it in a BULK quantity. Differential centrifugation is the technique of separation of different organelles of the cell based on their relative DENSITIES.

The correct answer is (a) True

Explanation: POLYMERASE CHAIN reaction (PCR) can generate large amounts of DNA, even from minuscule samples by amplifying the DNA material present in a SINGLE CELL. PCRs are also used in crime investigations.

The correct OPTION is (a) strength of IONIC BUFFER

For explanation: In ion-exchange chromatography, the proteins bind reversibly to the INERT resin through ionic BONDS. To displace and eventually elute the bound proteins the ionic strength of buffer can be increased.

Correct answer is (a) True

For explanation: Trypsin is a PROTEOLYTIC enzyme and is used for dissociating the TISSUE into single cells. During the primary CULTURE, tissue samples are taken generally from the embryos rather than the adult organism because of easy dissociation.

The correct option is (b) immobilizes

The explanation is: A fixative is used for the preparation of a section – a thin slice of the ORIGINAL ORGANELLE retaining all the organelles. A fixative is used for the preparation of the sections; by PENETRATING the CELL membranes fixatives immobilize the MACROMOLECULAR components.

The correct answer is (c) green

Explanation: The wavelength of 500 to 565 falls in the green COLOR range. 527 nm is used in transmission ELECTRON MICROSCOPY to IMPROVE resolution.

Correct choice is (c) agarose

For explanation: Agarose gels are used for the separation of large nucleic acids using the technique of gel electrophoresis. Agarose gels have a greater porosity and MAKE it easy for the larger proteins to MIGRATE under the INFLUENCE of an electric FIELD.