Zoology MCQs for NEET — Practice Questions with Answers

b) Insulin, a hormonal protein secreted by pancreas controls the metabolism of glucose.

(b) Vitamin B₁₂ or cyanocobalamin is C₆₃H₈₈O₁₄N₁₄PCo.

Adenosine is a nucleoside formed by the combination of an adenine purine base and a ribose sugar. Nucleosides are the building blocks of nucleotides, which are the monomers that make up nucleic acids like DNA and RNA.

(b) Glycine is optically inactive:

NH₂.CH₂.COOH is glycine

(d) When protein is subjected to physical change like change in temperature or chemical change like change in pH, the hydrogen bonds are disturbed. As a result, globules unfolds and helix get uncoiled and protein losses its biological activity. Hence, the denaturation of protein makes the protein inactive.

(c) The central dogma of molecular genetics states that

$\mathrm{DNA} \stackrel{\mathrm{Transcription}}{\to }\mathrm{RNA} \stackrel{\mathrm{Translation}}{\to } \mathrm{Protein}$

Thus, option (c) is correct.

In a protein molecule, different amino acids are linked together by peptide bonds. A peptide bond is a covalent bond formed between the carboxyl group of one amino acid and the amino group of another amino acid, releasing a water molecule.

(a) In DNA, two helically twisted strands connected together by steps. Each strand consists of altemating molecules of deoxyribose at 2'-position and phosphate groups.

On the other hand, in RNA, the pentose sugar has an identical structure with deoxyribose sugar except that there is an-OH group instead of -H on carbon atom 2'.

Hence, it is only called ribose.

Sucrose, also known as table sugar, is a non-reducing sugar. It is a disaccharide composed of one molecule of glucose and one molecule of fructose. Unlike reducing sugars like glucose and maltose, sucrose does not have a free aldehyde or ketone group, making it a non-reducing sugar.