Practice free Zoology NEET multiple-choice questions online with instant answers and detailed explanations. No login required.
Which of the following biomolecules does have a phosphodiester bond?
Phosphodiester bond is in responsible for linking nucleotides in nucleic acid (DNA and RNA).
The chitinous exoskeleton of arthopods is formed by the polymerisation of
The chitinous exoskeleton of arthropods is formed by the polymerisation of N-acetyl glucosamine, which is a derivative of glucose. It is also a characteristic component of the cell wall of fungi, the radulae of molluscs and the beaks and internal shells of cephalopods, including squid and octopuses.
Which one of the following statements is correct, with reference to enzymes?
(b) Holoenzyme It is a conjugate complete catalytically active enzyme together with its coenzyme.
Apoenzyme The protein part of catabolically active enzyme is called apoenzyme.
Coenzyme Some enzymes require additional organic or metallo-organic molecules for their activity. These molecules are called coenzyme. So, holoenzyme is apoenzyme together with coenzyme hence option (b) is correct.
Which of the following are not polymeric?
(d) Among the given options except lipids all are polymers. These are formed by the polymerisation of monomers. The basic unit of lipid are fatty acids and glycerol molecules that do not form repetitive chains. Instead they form triglycerides from three fatty acids and one glycerol molecule.
Protein monomers are amino acids and they bond together in repetitive chain just as, carbohydrate monomers are monosaccharides.
A non-proteinaceous enzyme is
(b) Ribozyme is a form of ribosomal RNA (23 SrRNA) which acts as a catalyst in splicing of RNA during protein synthesis. It is the only non-protein enzyme known so far, rest all the enzymes are proteinaceous. Hence, option (b) is correct.
Which of the following biomolecules is common to respiration-mediated breakdown of fats, carbohydrates and proteins?
(d) Carbohydrates, fats and proteins all can be used as a substrate in cellular respiration. All of them first get converted to acetyl Co-A to enter into Kreb's cycle of aerobic cellular respiration. Thus, it is the common factor of respiration entering Kreb's cycle after breakdown of carbohydrates, fats and proteins
Which of the following is the least likely to be involved in stabilising the three-dimensional folding of most proteins?
(d) Ester bonds are the least likely to be involved in stabilising the 3D-folding of most proteins. A long protein chain gets folded upon itself like a hollow woolen ball, giving rise to a tertiary structure (3D) structure. This structure is stabilised by several type of bonds, i.e. hydrogen bonds, ionic bonds, Vander waal's interactions, covalent bonds and hydrophobic bonds. Ester bond is formed between sugar and phosphate in a nucleotide and is not involved in stability of a polypeptide chain. Thus, option (d) is correct.
Which one of the following statements is wrong?
(c) Glycine is the simplest amino acid in which functional group 'R' is replaced by hydrogen atom (H).
A typical fat molecule is made up of
(a) A typical fat molecule is triglyceride formed by esterification of one glycerol and three fatty acid molecules. The three fatty acids can be of same type or different depending on type of the fat molecules.
Which one of the following statement is incorrect ?
(d) In the presence of a competitive inhibitor, Vmax remains unchanged while Km increases.
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