Given below are two statements: Statement I: textD-(+)-glucose + textD-(+)-fructose xrightarrow-mathrmH_2mathrmO textsucrose qquad textsucrose xrightarrowtextHydrolysis textD-(+)-glucose + textD-(+)-fructose$\text{D-(+)-glucose} + \text{D-(+)-fructose} \xrightarrow{-\mathrm{H}_2\mathrm{O}} \text{sucrose} \qquad \text{sucrose} \xrightarrow{\text{Hydrolysis}} \text{D-(+)-glucose} + \text{D-(+)-fructose}$ Statement II: Invert sugar is formed during sucrose hydrolysis. In the light of given statements, choose the correct answer from the options given below:

### Core Logic To assign D or L configurations to ketohexoses like fructose, locate the configuration at the highest-numbered asymmetric carbon atom (carbon-5). * In D-fructose, the -textOH$-\text{OH}$ group on C-5 is situated on the \right side in the Fischer projection. * In L-fructose, the configuration of every stereocenter is inverted compared to D-fructose, meaning the -textOH$-\text{OH}$ group on C-5 is situated on the \left hand side.

### Pattern Recognition Shortcut: L-sugar means the stereocenter farthest from the carbonyl group (C5 for hexoses) has its -textOH$-\text{OH}$ pointing \left. Ensure it is the perfect non-superimposable mirror image of standard D-fructose. ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 12 Chemistry: Biomolecules

### Related Formula textDipeptide X xrightarrowtextHydrolysis textAmino Acid y + textAmino Acid z$$\text{Dipeptide } X \xrightarrow{\text{Hydrolysis}} \text{Amino Acid } y + \text{Amino Acid } z$$ ### Core Logic - Since **y** reacts with nitrous acid (HNO_2$HNO_2$) to give lactic acid (CH_3-CH(OH)-COOH$CH_3-CH(OH)-COOH$), **y** must be alanine (CH_3-CH(NH_2)-COOH$CH_3-CH(NH_2)-COOH$). - When glycine (NH_2-CH_2-COOH$NH_2-CH_2-COOH$) is heated, two molecules undergo intermolecular cyclization to produce a six-membered diketopiperazine ring as shown in the problem diagram. Therefore, **z** is glycine. Hence, combining residue **y** (alanine) and **z** (glycine), the dipeptide X is **alanine-glycine**. ### Step 1: Stepwise Degradation Overview Reaction scheme: 1. Alanine-Glycine linkage rightarrow$\rightarrow$ Alanine + Glycine 2. textAlanine + HNO_2 rightarrow textLactic acid + N_2uparrow + H_2O$\text{Alanine} + HNO_2 \rightarrow \text{Lactic acid} + N_2\uparrow + H_2O$ 3. 2 times textGlycine xrightarrowDelta textCyclic diketopiperazine + 2H_2O$2 \times \text{Glycine} \xrightarrow{\Delta} \text{Cyclic diketopiperazine} + 2H_2O$ ### Pattern Recognition Lactic acid generation from alpha-amino acids via nitrous acid deamination is a definitive chemical fingerprint for alanine. The unsubstituted cyclic diketopiperazine product confirms glycine as the second component. ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 12 Chemistry: Biomolecules

### Core Logic A dipeptide sequence is parsed strictly from the **N-terminus** to the **C-terminus**. Therefore, in Gly-Ala: * **Glycine (Gly)** must supply its carbonyl end for coupling. * **Alanine (Ala)** must provide its free amine end. To drive peptide bond formation via the explicit elimination of HCl$HCl$, the carboxyl group of glycine must be pre-activated as an acyl chloride variant: mathrmNH_2-CH_2-COCl$\mathrm{NH_2-CH_2-COCl}$. This reacts smoothly with the unsubstituted amine terminus of alanine, mathrmNH_2-CH(CH_3)-COOH$\mathrm{NH_2-CH(CH_3)-COOH}$, liberating HCl$HCl$ to form the amide bridge linkage: mathrmNH_2-CH_2-CONH-CH(CH_3)-COOH$\mathrm{NH_2-CH_2-CONH-CH(CH_3)-COOH}$. ### Pattern Recognition peptide naming structure sequence convention dictates: textFirst name = textN-terminus acyl donor$\text{First name} = \text{N-terminus acyl donor}$, textSecond name = textC-terminus amine acceptor$\text{Second name} = \text{C-terminus amine acceptor}$. ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 12 Chemistry: Biomolecules

### Related Formula textG-C base pairing implies 3 text Hydrogen bonds$$\text{G-C base pairing} \implies 3 \text{ Hydrogen bonds}$$ textA-T base pairing implies 2 text Hydrogen bonds$$\text{A-T base pairing} \implies 2 \text{ Hydrogen bonds}$$ ### Core Logic Let's audit the nucleotide base distribution across the given single strand structure: 5' - G - G - C - A - A - A - T - C - G - G - C - T - A - 3'$$5' - G - G - C - A - A - A - T - C - G - G - C - T - A - 3'$$ * **Count the Guanine (G) and Cytosine (C) bases:** Bases present: G_1, G_2, C_3, C_8, G_9, G_10, C_11$G_1, G_2, C_3, C_8, G_9, G_{10}, C_{11}$ implies$\implies$ Total of 7 bases. Each G-C interaction forms 3 hydrogen bonds: textBonds_G-C = 7 times 3 = 21$$\text{Bonds}_{G-C} = 7 \times 3 = 21$$ * **Count the Adenine (A) and Thymine (T) bases:** Bases present: A_4, A_5, A_6, T_7, T_12, A_13$A_4, A_5, A_6, T_7, T_{12}, A_{13}$ implies$\implies$ Total of 6 bases. Each A-T interaction forms 2 hydrogen bonds: textBonds_A-T = 6 times 2 = 12$$\text{Bonds}_{A-T} = 6 \times 2 = 12$$ Summing them up yields the total hydrogen bonds in the helix: textTotal Htext-bonds = 21 + 12 = 33$$\text{Total } H\text{-bonds} = 21 + 12 = 33$$ ### Pattern Recognition Quick check optimization: Total Bonds = 3 times (\#G + \#C) + 2 times (\#A + \#T)$3 \times (\#G + \#C) + 2 \times (\#A + \#T)$. ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 12 Chemistry: Biomolecules

### Related Formula textProtein xrightarrowtextHydrolysis textPeptides xrightarrowtextHydrolysis alphatext-amino acids$$\text{Protein} \xrightarrow{\text{Hydrolysis}} \text{Peptides} \xrightarrow{\text{Hydrolysis}} \alpha\text{-amino acids}$$ ### Core Logic Statement (I) is incorrect because the complete hydrolysis of both oligopeptides and proteins yields alpha$\alpha$-amino acids, not beta$\beta$-amino acids. Statement (II) is incorrect because fibrous proteins are inherently water-insoluble structural materials. Denaturation typically disrupts the tertiary and secondary structures of water-soluble globular proteins, making them insoluble. ### Step 1: Final Conclusion Since both Statement I and Statement II are false, option (3) is the correct choice. ### Pattern Recognition All naturally occurring proteins are polymers of alpha$\alpha$-amino acids, so any statement mentioning beta$\beta$-amino acids as direct translation products can be confidently ruled out. Fibrous proteins (like keratin or collagen) are structural and always insoluble, unlike globular proteins. ### Evaluation Rubric / Model Answer null ### Chapter Mix Class 12 Chemistry: Biomolecules