Which of the following is the correct structure of L-fructose?

Related Formula

Nucleotides bond phosphodiester linkage:

Core Logic

Two nucleotides are joined together by phosphodiester linkage between 5'$5'$ and 3'$3'$ carbon atoms of the pentose sugar.

Pattern Recognition

Proteins arrow$\rightarrow$ Peptide, Carbohydrates arrow$\rightarrow$ Glycosidic, Proteins/Cysteine arrow$\rightarrow$ Disulphide, Nucleic Acids arrow$\rightarrow$ Phosphodiester linkage.

Chapter Mix

Class 12 Chemistry: Biomolecules

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