Problem 86 - Objective Biology for NEET

Question

Phosphorus is a structural element in (a) Fat (b) Starch (c) Nucleotide (d) Carbohydrate

Step-by-Step Solution

Answer

Phosphorus is a structural element in nucleotides.

Step 1: Understanding fat structure

Investigate the structure of fats. Fats are primarily composed of glycerol and fatty acids, which don't contain phosphorus. So option (a) is incorrect.

Step 2: Analysing starch structure

Investigate the structure of starch. Starch is a polysaccharide composed of glucose units, and does not contain phosphorus. So option (b) is incorrect.

Step 3: Investigating nucleotide structure

Investigate the structure of nucleotides. Nucleotides are the building blocks of DNA and RNA, and each nucleotide is made up of a nucleobase, a five-carbon sugar (ribose or deoxyribose) and at least one phosphate group. So, phosphorus is present in nucleotides. Option (c) is correct.

Step 4: Checking Carbohydrate structure

Investigate the structure of carbohydrates. Carbohydrates are formed by carbon, hydrogen, and oxygen, but they don’t contain phosphorus. So option (d) is incorrect.

Key Concepts

Nucleotide Structure

Nucleotides are the fundamental building blocks of genetic material, such as DNA and RNA. They are structured with three key components: a nucleobase, a five-carbon sugar, and a phosphate group.
A nucleobase could be either a purine (adenine or guanine) or a pyrimidine (cytosine, thymine, or uracil). These bases are crucial for encoding genetic information.
The five-carbon sugar, which may be ribose or deoxyribose, helps form the sugar-phosphate backbone of the nucleotide chain.

• In DNA, the sugar is deoxyribose.
• In RNA, the sugar is ribose.

Finally, the phosphate group is responsible for linking nucleotides together, creating long chains.
This phosphate linkage is what gives nucleic acids their acidic properties.
Thus, phosphorus within the phosphate group plays a pivotal role in the structure of nucleotides.

Phosphate Group

The phosphate group is a vital component of nucleotides, contributing essential properties to DNA and RNA. Each nucleotide comprises at least one phosphate group attached to the five-carbon sugar.
This presence of phosphorus forms a bridge between nucleotides, providing structural stability and continuity in chains of nucleic acids.
The phosphate group bears a negative charge, which helps in the pairing of DNA and RNA strands through hydrogen bonding.
Through this bonding, phosphates influence the three-dimensional structure of the entire nucleic acid molecule.

• Phosphates enable the storage and transmission of genetic information.
• They also allow DNA to replicate during cell division.

Understanding the phosphate group is key to recognizing how nucleotides act as units of genetic material.

DNA and RNA

DNA and RNA are complex chains of nucleotides that play crucial roles in genetics and the bodily functions of all living organisms.
Both these molecules are essential for storing and conveying genetic information necessary for life.
DNA, or deoxyribonucleic acid, contains the blueprint of biological information, guiding the development and functioning of organisms.
RNA, or ribonucleic acid, is primarily involved in translating these blueprints to synthesize proteins.

• DNA is typically double-stranded, forming the iconic double helix shape.
• RNA is usually single-stranded, playing varied roles in cells.

Each nucleotide in DNA and RNA features a phosphate group, a nucleobase, and a sugar. The sugar and phosphate form the backbone of the strand, while the bases pair with complimentary bases, enabling the genetic coding mechanism.
This comprehensive composition allows DNA and RNA to execute their roles efficiently in genetic inheritance and protein synthesis.