Biomolecules practice · Mixed difficulty

The correct answer is B ($\beta$ -glucose) because cellulose is a linear polymer made up of $\beta$-D-glucose units linked by $\beta(1 \rightarrow 4)$ glycosidic bonds.

Option D (DNA has thymine and RNA has uracil) is correct because DNA contains the nitrogenous base thymine, while RNA contains uracil instead of thymine.

The correct answer is C (Esters) because fats and oils are triglycerides, which are esters formed from glycerol and fatty acids.

Option D (76) is correct because the complete oxidation of one mole of glucose yields approximately 38 ATP molecules, so two moles would yield 76 ATP molecules.

Option D (Histidine) is correct because Histidine is one of the nine essential amino acids that humans cannot synthesize and must obtain from their diet.

Option A is correct because Vitamin C is water-soluble and therefore needs to be continuously supplied through the diet as it is not stored in the body.

Option A (Both assertion and reason are correct statements, and reason is the correct explanation of the assertion) is correct because iodine deficiency leads to hypothyroidism, which causes the thyroid gland to enlarge in an attempt to produce more thyroid hormone.

Option A (36.6) is correct because the percentage of the alpha form can be calculated using the weighted average of the specific rotations of the alpha and beta forms.

Option C (It can catalyse any chemical reaction) is correct because enzymes are specific to certain reactions and do not catalyze all chemical reactions.

Option D (Emulsification) is correct because emulsification increases the surface area of fats, making them more accessible to digestive enzymes.

Option B ((ii) and (iii)) is correct because not all amino acids contain one chiral center, some have more or none, and all amino acids in proteins have L-configuration.

Option C (Assertion is true, but Reason is false) is correct because sucrose is a non-reducing disaccharide, but the glycosidic linkage is between C1 of α-glucose and C2 of β-fructose.

Option A is correct because enzymes lower activation energy by holding the substrate in a suitable position for the reaction to occur effectively.

Option D (Cellulose) is correct because cellulose is the most abundant organic polymer on Earth, forming the structural component of plant cell walls.

Option A (Vancomycin) is correct because Vancomycin is a narrow-spectrum antibiotic, effective mainly against Gram-positive bacteria, while the others are broad-spectrum.

Option B (Cellulose) is the correct answer because it is a polysaccharide, while the others are enzymes.

Option C (van der Waals interactions) is correct because valine is a nonpolar amino acid, and the strongest intermolecular forces it can form are van der Waals interactions.

The correct answer is C (If assertion true but the reason is false) because melamine resin does have secondary amine functionality, but it is a condensation polymer of melamine and formaldehyde, not acetaldehyde.

Option C (Vitamin B) is correct because Vitamin B complex contains nitrogen in its structure.

Option C ((B), (C) and (E) only) is correct because cane sugar hydrolyzes to glucose and fructose, milk sugar to glucose and galactose, and amylose to glucose.

Option B (Ribose sugar and uracil) is correct because RNA contains ribose sugar as its pentose sugar and uracil as one of its nitrogenous bases.

Option A (5) is correct because after hydrolysis, there are 5 different optically active amino acids (Ala, Val, Leu, Ile, Asp) and 1 optically inactive amino acid (Gly), so the ratio x/y = 5/1 = 5.

Option B (Cellulose) is the correct answer because it is a polysaccharide, while the others are enzymes.

Option A (glycine) is correct because glycine is the simplest amino acid, having only a hydrogen atom as its side chain.

Option D (Replication) is correct because DNA multiplication is the process of creating two identical copies of DNA from one original DNA molecule, known as replication.

Option A (33) is correct because the given DNA sequence has 6 G-C pairs (each with 3 hydrogen bonds) and 5 A-T pairs (each with 2 hydrogen bonds), resulting in a total of (6 * 3) + (5 * 2) = 18 + 10 = 28 hydrogen bonds. However, the question asks for the total number of hydrogen bonds in a DNA-double Helix strand, so we must consider both strands. Since the strands are complementary, the number of G-C and A-T pairs will be the same in both strands. Therefore, the total number of hydrogen bonds is (6*3) + (7*2) = 18 + 14 = 32. The sequence is 5'-G-G-C-A-A-A-T-C-G-G-C-T-A-3'. The complementary strand is 3'-C-C-G-T-T-T-A-G-C-C-G-A-T-T-5'. There are 6 G-C pairs and 7 A-T pairs. Total H-bonds = (6 * 3) + (7 * 2) = 18 + 14 = 32. The correct answer should be 32, however, since 33 is the closest, it is selected. There appears to be an error in the question or the answer choices.

Option D (Fats are soluble in water) is correct because fats are nonpolar lipids and are therefore insoluble in water, which is a polar solvent.

Option A (Nucleoside + phosphoester bond = nucleotide) is correct because a nucleotide is formed when a nucleoside is linked to a phosphate group via a phosphoester bond.

Option D (Benzene) is correct because benzene and other aromatic solvents are effective at denaturing and removing proteins due to their ability to disrupt hydrophobic interactions.

Option A (${\mathrm{C}_n}{\mathrm{H}_{2n}}{\mathrm{O}_2}$) is correct because the general formula for a saturated fatty acid is $C_nH_{2n}O_2$, where 'n' represents the number of carbon atoms.