Given below are two statements : Statement I : D-glucose pentaacetate reacts with 2, 4-dinitrophenylhydrazine. Statement II : Starch, on heating with concentrated sulfuric acid at 100°C$100^{\circ}\mathrm{C}$ and 2-3 atmosphere pressure produces glucose. In the light of the above statements, choose the correct answer from the options given below

Core Logic

Proteins are natural biopolymers. The fundamental building blocks (monomers) of all naturally occurring proteins are α$\alpha$-amino acids. In these molecules, both the amino group (-NH₂$-NH_2$) and the carboxyl group (-COOH$-COOH$) are attached to the exact same carbon atom, designated as the α$\alpha$-carbon.

Because they are polymers of α$\alpha$-amino acids linked by peptide bonds, the hydrolysis of proteins (acidic, basic, or enzymatic) will cleave these peptide bonds to yield the constituent α$\alpha$-amino acids.

Chapter Mix

Class 12 Chemistry: Biomolecules

Core Logic

A. RNA is regarded as the reserve of genetic information. (False - DNA is the reserve of genetic information). B. DNA molecule self-duplicates during cell division. (True - through replication). C. DNA synthesizes proteins in the cell. (False - RNA molecules synthesize proteins via translation, DNA only provides the code). D. The message for the synthesis of particular proteins is present in DNA. (True - the genetic code lies in the base sequence of DNA). E. Identical DNA strands are transferred to daughter cells. (True - through accurate replication and cell division, genetic continuity is maintained).

Step 1: Final Conclusion

The true statements are B, D, and E. Total number of correct statements is 3.

Chapter Mix

Class 12 Chemistry: Biomolecules

Core Logic

Fehling's reagent is reduced by reducing sugars to give a reddish-brown precipitate of Cu₂O$Cu_2O$. Reducing sugars must have a free aldehyde/ketone group or a hemiacetal linkage that can open to form an aldehyde. Sucrose is a non-reducing sugar because its anomeric carbons (C1 of glucose and C2 of fructose) are tied up in a glycosidic linkage, leaving no free hemiacetal group.

Step 1: Analyzing the options

Lactose, glucose, and maltose are all reducing sugars and will give a positive Fehling's test. Sucrose does not.

Pattern Recognition

Sucrose = non-reducing sugar. Maltose, Lactose = reducing sugars. Monosaccharides (glucose, fructose) = always reducing.

Chapter Mix

Class 12 Chemistry: Biomolecules

Core Logic

Vitamins are broadly classified into two groups based on solubility:

• Fat-soluble vitamins: Vitamins A, D, E, and K. These are stored in the liver and adipose (fat-storing) tissues.
• Water-soluble vitamins: B group vitamins and Vitamin C. These are readily excreted in urine and cannot be stored in the body (with the exception of Vitamin B₁₂$B_{12}$, which can be stored in the liver).

Step 1: Final List

The vitamins that can be stored in the body from the given list are A, D, E, K, and B₁₂$B_{12}$. Total number = 5$5$.

Chapter Mix

Class 12 Chemistry: Biomolecules

Core Logic

Matching the reactions of glucose: (A) Glucose does not react with NaHCO₃$NaHCO_3$, so there is no reaction. (A arrow$\rightarrow$ II) (B) Oxidation of glucose with strong oxidizing agents like HNO₃$HNO_3$ yields a dicarboxylic acid called saccharic acid. (B arrow$\rightarrow$ IV) (C) Prolonged heating of glucose with HI$HI$ forms n-hexane, indicating a straight chain of six carbon atoms. (C arrow$\rightarrow$ III) (D) Oxidation with mild agents like bromine water converts glucose to gluconic acid. (D arrow$\rightarrow$ I)

Chapter Mix

Class 12 Chemistry: Biomolecules