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The correct answer is (a) AUG

The BEST I can explain: The START CODON indicates the start of protein translation after the 5’-untranslated region (UTR) and the ribosome binds to the start codon in the mRNA. AUG is the sole start codon and codes for the amino acid Methionine. UAA, UAG and UGA are the THREE stop codons that INDICATE the termination of protein translation.

The CORRECT CHOICE is (c) Increase in product to a certain level

The BEST I can EXPLAIN: Feedback inhibition refers to the inhibition of enzyme activity when a certain end product is increased beyond a certain level. Due to accumulation of the product, the enzyme does form the enzyme-substrate complex in order to form the product, which is already in excess.

Right choice is (b) SALIVARY gland of larvae of fruit fly

The explanation: Polytene chromosomes are a type of giant chromosomes which are many TIMES longer in length than NORMAL chromosomes. Polytene chromosomes are found in the salivary gland of a larval fruit fly and show SEVERAL DISTINCT darkly stained bands.

Correct ANSWER is (a) True

For EXPLANATION I would SAY: Cellular metabolism is essentially a non-equilibrium metabolism; that is the ratio of REACTANTS to products is maintained in a non-equilibrium state. This makes most of the reactions irreversible.

Right option is (a) superior phenotype of a hybrid

For explanation: Hybrid vigour is the phenomenon of INCREASED vigour in the hybrids as compared to both of its parents. This phenomenon came to light in the 20th century in CORN F1 hybrids. The resulting hybrid plant had a higher GROWTH rate, was PHENOTYPICALLY superior and had increased yield as compared to both the parents.

The correct option is (b) 9

The best explanation: The nucleosome is COMPOSED of 8 histone PROTEINS known as Histone Octamer and a separate H1 protein. The histone proteins present are two H2A, two H2B, two H3 and two H4 proteins ALONG with a single H1 protein. The DNA strand WOUNDS around the DNA Octamer to produce a nucleosome unit.

Correct choice is (c) Dehydrogenase

Explanation: Dehydrogenase is the enzyme that CATALYZES the REMOVAL of a PROTON tor hydrogen from a reactant to NAD+. NADH is the reduced form of NAD+, which is a cofactor in the electron transport chain.

Right option is (b) False

Easy explanation: Unlike the CELLS of SKELETAL muscles, which CONVERT pyruvate to lactate in case of low OXYGEN supply; the yeast cells convert pyruvate to ethanol.

The correct ANSWER is (a) Tipranavir

To elaborate: In noncompetitive inhibition, the substrate and inhibitor do not COMPETE for the active site of the enzyme and the inhibitor generally act at other site to bind to the enzyme. The level of inhibition depends on concentration of the inhibitor. Tipranavir is non-COMPETITIVE inhibitor of the protease produced by HIV when HIV infects a white blood CELL. RITONAVIR is a competitive inhibitor of the protease and resembles the its peptide substate.

The correct OPTION is (b) False

Explanation: The processes having NEGATIVE Gibbs FREE energy (-ΔG) are TERMED as exergonic; are thermodynamically favored and are spontaneous in nature. Processes having +ΔG are endergonic, thermodynamically unfavorable and non-spontaneous.

Right ANSWER is (C) YELLOW signal

The BEST EXPLANATION: In FISH, the green signal indicates presence of the BCR gene and the red signal indicate the presence of the ABL gene. The red-green fusion (yellow) signal confirms a BCR/ABL translocation.

The correct option is (a) Carbohydrates

To explain: ENZYMES are the catalysts RESPONSIBLE for virtually everything that TAKES place inside a cell. Without these catalysts the cellular METABOLISM and bioenergetics would be imperceptible.

The correct option is (b) Human ABO BLOOD group SYSTEM

The best I can explain: When two different alleles are crosses and neither of them is dominant and recessive and both get EXPRESSED in the phenotype offspring, then such a genetic scenario is known as codominance. In the ABO Blood group system of humans, a person with A protein has blood type A and a person with B protein has blood type B. If a person with blood type A mates with person with blood type B, then the dominant A and B GENES will be co-expressed in the offspring and he will have blood type ‘AB’.

Correct answer is (c) PHOSPHORYLATION

Explanation: Glycolysis BEGINS with the addition of a sugar molecule to a phosphate group. Phosphorylation ACTIVATES the sugar molecule to take part in later steps of the process and ALSO reduce the CONCENTRATION of glucose in the cytoplasm, promoting continued diffusion from blood to the cell.

Right answer is (b) inhibit

Explanation: Feedback inhibition acts as a check POINT. If the formation of PRODUCTS is too much, the product itself acts as the inhibitor of the enzyme thus causing the reaction to STOP. Feedback inhibition loop is found in most of the cell’s anabolic and catabolic PROCESSES.

The CORRECT answer is (B) lactate

Explanation: In case of repeated contraction, the oxygen levels DROP down and MAKE it difficult to keep up with the cell’s metabolic demands. Under these conditions, skeletal muscle cells regenerate NAD⁺ by converting pyruvate to lactate.

Right answer is (a) Molybdenum

The EXPLANATION: The process of FORMATION of ammonia from HYDROGEN and nitrogen is KNOWN as the HABER’s process. The enzyme that catalyzes the Haber’s reaction needs Molybdenum (Mo) as a cofactor.

Right choice is (a) Reversible inhibitors

To elaborate: Irreversible inhibitors are those that bind very TIGHTLY to an enzyme, often by forming a covalent bond to one of its AMINO acid residues. Reversible inhibitors bind loosely to an enzyme and thus are readily displaced. Competitive inhibitors are reversible inhibitors of enzyme that COMPETE with a SUBSTRATE for access to the ACTIVE site of the enzyme.

The correct choice is (a) Rate will INCREASE

The explanation is: The rate of an enzymatic reaction will increase with temperature but only UPTO a certain limit. Too MUCH HEAT energy causes the enzyme to denature. This rate varies among different enzymes.

Right ANSWER is (d) enzyme

For explanation: Chymotrypsin is an enzyme that DIGESTS food proteins WITHIN the SMALL INTESTINE. The active site of this enzyme contains partial positive and partial negative charges.

Correct option is (d) Hypertrichosis

The explanation: GENES that are Y linked are CALLED Holandric genes. Conditions such as Hypertrichosis(which is excessive growth of HAIR) and COLOUR BLINDNESS(inability to see and perceive colour) are Y linked disorders, that is they are only inherited by males.

The CORRECT ANSWER is (C) Kinase

The explanation is: Kinase is the enzyme that transfers phosphate group from one protein to another. Phosphorylase catalyzes ADDITION of phosphate group from an inorganic phosphate to an acceptor. Phosphatase enzyme cleaves a phosphate in presence of water.

The correct answer is (d) Exergonic

To elaborate: Hydrolysis of ATP is the most important CHEMICAL reaction in a living CELL. It is highly favorable and exergonic with a standard FREE energy (ΔG⁰’) between reactants and products equal to -7.3 kcal/mol.

Right option is (b) semi-conservative

For explanation I WOULD say: In DNA replication , the two daughter STRANDS unwind and are used as template for the formation of a new DNA STRAND. As a result, one strand in conserved and a new strand is produced by taking the conserved strand as a template. Thus, DNA replication is a semi-conservative process.

Correct OPTION is (a) Ribosomal A site

Easy explanation: During translation, the aminoacyl tRNA CARRYING the desired amino acid approaches the A site on the RIBOSOME. It then further moves to the P site and becomes peptidyl tRNA, which initiates the formation of a peptide bond between the amino acid and the growing peptide CHAIN. The peptidyl tRNA leaves through the E site of ribosome.

Correct CHOICE is (C) 36

The EXPLANATION: In one cycle of glycolysis, 6 ATP is obtained. Each MOLECULE of glucose gives 2 pyruvate which corresponds to 6 ATP. There is also formation of 2 acetyl-CoA molecules which is about 24 ATP. Thus each molecule of Glucose give 36 ATP. ( Note that about 34 ATP molecules are consumed in glycolysis thus the net yield is 2 ATP).

Right CHOICE is (b) Have multiple subunits

For explanation: ALLOSTERIC enzymes are enzymes that change conformation upon binding of an effector and AFFECTS the binding affinity at a different binding site. Allosteric enzymes are the exception to Michaelis-Menten KINETICS and usually has multiple coupled subunits or DOMAINS.

Correct CHOICE is (a) GLUCONEOGENESIS

The best I can explain: The ANABOLIC PATHWAY that LEADS to the formation of glucose is referred to as gluconeogenesis. A cell can synthesize glucose at the same it is utilizing glucose as the source of chemical energy.

The correct answer is (a) enzymes, ribozymes

The best I can EXPLAIN: RNA CATALYSTS are called ribozymes whereas protein catalysts are called enzymes. Most of the catalysts are enzymes MADE of PROTEINS.

Right answer is (b) exothermic

Explanation: Energy can neither be created nor be DESTROYED. It is only transduced from one form into another. Heat is also a form of energy; REACTIONS in which heat is lost to the surroundings are termed as exothermic reactions and those in which heat is gained from the system are termed as ENDOTHERMIC reactions.

The CORRECT choice is (a) constant, increases

The best explanation: According to the FIRST and SECOND laws of THERMODYNAMICS, the energy of the universe remains constant however the entropy increases OWING to the randomness.

The correct choice is (b) TRANSCRIPTION

Easiest explanation: Lampbrush chromosomes are a type of giant chromosomes FOUND in the growing oocytes of amphibians. Twin loops arise on either SIDE of the chromosome in meiotic prophase. This is due to the ACTIVE transcription of many genes.

Correct answer is (d) All of the mentioned

The explanation is: Adenosine triphosphate or ATP is the main source of energy in cells. It RELEASES energy by breaking into Adenosine diphosphate (ADP) and inorganic phosphate. It PLAYS a role in solute transport across cell membranes through ATPase channels. It is the precursor of Adenine, which helps in the FORMATION of DNA.

Right choice is (d) REDUCING power

Explanation: A CELL’s reservoir of NADPH is a measure of its reducing power and the usable ENERGY. NADPH is a COMPOUND similar to NADH but with an additional phosphate group.

The correct answer is (b) False

Explanation: Allosteric site is SPATIALLY DIFFERENT from enzyme’s active site. It is the site where a COMPOUND can bind and LEAD to inhibition or activation of an enzyme.

The correct option is (b) cofactors

The EXPLANATION is: The non-protein CONSTITUENTS of conjugated proteins (that act as ENZYMES) are called cofactors. These cofactors can be inorganic metals or organic COENZYMES.

The correct choice is (a) LACTATE

The best I can explain: In aerobic respiration, the PYRUVATE is converted to two-carbon COMPOUND acetyl CoA which enters the Kreb’s cycle to release carbon dioxide and energy. In ANAEROBIC respiration, DUE to absence of oxygen, the pyruvate is converted to lactate. In yeast fermentation, pyruvate is converted to alcohol and carbon dioxide.

The correct choice is (c) Enzymes decrease the activation energy of the reaction

The best I can explain: Chemical REACTIONS need CERTAIN covalent bond breakage WITHIN the REACTANTS. For this, the reactants must contain SUFFICIENT kinetic energy called the activation energy. Enzymes act as catalysts that speed up the reaction by lowering the activation energy required for breaking the covalent bonds.