Test: Polysaccharides and Nucleic Acid (May 27) - NEET MCQ

The complementary base pairs of guanine with cytosine and adenine with thymine connect to one another using hydrogen bonds. In addition to holding the DNA strands together, the hydrogen bonding between the complementary bases also sequester the bases in the interior of the double helix. Since, the option of Guanine and Cytosine is not provided. Hence, the correct option is Option C. 

Cellulose is made up of Glucose like starch . Cellulose is composed of a long chain of at least 500 glucose molecules. Cellulose is these a polysaccharide chains are arranged in parallel arrays to form cellulose microfibrills.

• Definition: Glycogen is a polysaccharide that serves as a form of energy storage in animals and fungi.



• Composition: It is composed of repeating units of glucose molecules linked together in a branched structure.



• Role: Glycogen is stored in the liver and muscles and serves as a readily available source of energy when blood glucose levels are low.



• Synthesis: Glycogen synthesis is known as glycogenesis and involves the addition of glucose molecules to the existing glycogen molecule through the action of enzymes.



• Breakdown: When energy is needed, glycogen is broken down into glucose through a process called glycogenolysis.



• Regulation: The synthesis and breakdown of glycogen are tightly regulated by hormones such as insulin and glucagon to maintain blood glucose levels within a normal range.

In a DNA molecule, the two strands are not parallel, but intertwined with each other. Each strand looks like a helix. The two strands form a "double helix" structure, which was first discovered by James D. Watson and Francis Crick in 1953. In this structure, also known as the B form, the helix makes a turn every 3.4 nm, and the distance between two neighbouring base pairs is 0.34 nm. Hence, there are about 10 pairs per turn. The intertwined strands make two grooves of different widths, referred to as the major groove and the minor groove, which may facilitate binding with specific proteins.
So, the correct answer is '3.4 nm'

The antiparallel strands of a DNA molecule that one strand turns anti-clockwise, the phosphate group of two DNA strands, at their ends, share the same position, the phosphate groups at the start of two DNA strands are in the opposite position and one strand turns clockwise.

According to Chargaff’s rule, the amount of adenine is always equal to that of thymine and the amount of guanine is always equal to that of cytosine.

A = T(120), G = C(120)

The total number of nucleotides would be 120 × 4 = 480.

Bacterial cell walls are made of peptidoglycan (also called murein), which is made from polysaccharide chains cross-linked by unusual peptides containing D-amino acids. Bacterial cell walls are different from the cell walls of plants and fungi which are made of cellulose and chitin, respectively.

• Glycogen Composition: Glycogen is a polysaccharide that is composed of repeated units of glucose.


• Homopolymer: A homopolymer is a polymer that is composed of only one type of monomer unit. In the case of glycogen, it is made up of glucose units.


• Glucose Units: Glucose is a simple sugar that serves as the building block for glycogen. When multiple glucose units are linked together through glycosidic bonds, they form the glycogen molecule.


• Function of Glycogen: Glycogen serves as a storage form of glucose in animals and humans. It is stored primarily in the liver and muscles and can be broken down into glucose when energy is needed.


• Difference from Starch: Glycogen is structurally similar to starch, which is another polysaccharide made of glucose units. However, glycogen is more highly branched, allowing for quick access to the stored glucose when needed for energy.

Cellulose is an important structural component of the primary cell wall of green plants, many forms of algae and the oomycetes.  Cellulose is the most abundant organic polymer on Earth. The cellulose content of cotton fiber is 90%, that of wood is 40–50%, and that of dried hemp is approximately 57%.

ATP was first discovered by the German chemist Karl Lohmann. Its structure is established some years later. In 1948 Alexander Todd (UK) synthesises ATP chemically. Vladimir Engelhart (Russia) notes in 1935 that muscle contractions require ATP.