Biomolecules Constituents of Life Miscellaneous

Biomolecules Constituents of Life Miscellaneous

Easy Questions

Biomolecules : Constituents of Life

Biomolecules Constituents of Life Miscellaneous
  1. Which one of the following aminoacids in proteins does NOT undergo phosphorylation? ​​








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    Proline is unique in that it is the only amino acid where the side chain is connected to the protein backbone twice, forming a five-membered nitrogen-containing ring. Proline is unable to occupy many of the main chain conformations easily adopted by all other amino acids. Proline can often be found in very tight turns in protein structures (i.e. where the polypeptide chain must change direction). It can also function to introduce kinks into alpha helices, since it is unable to adopt a normal helical conformation. Proline plays important roles in molecular recognition, particularly in intracellular signalling. The Proline side chain is very non-reactive and it does not undergo phosphorylation. ​

    Correct Option: C

    Proline is unique in that it is the only amino acid where the side chain is connected to the protein backbone twice, forming a five-membered nitrogen-containing ring. Proline is unable to occupy many of the main chain conformations easily adopted by all other amino acids. Proline can often be found in very tight turns in protein structures (i.e. where the polypeptide chain must change direction). It can also function to introduce kinks into alpha helices, since it is unable to adopt a normal helical conformation. Proline plays important roles in molecular recognition, particularly in intracellular signalling. The Proline side chain is very non-reactive and it does not undergo phosphorylation. ​

  1. Which of the following statements with respect to the orientation of the nitrogenous bases to the pentose sugars, and the puckering of the sugar, is correct?








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    ​Nitrogenous bases are always arranged in "anti" positions to their corresponding pentose sugar moieties. In B-form of DNA, sugar puckering occurs predominantly in the C2 position of the pentose sugar. The sugar pucker determines the shape of the a-helix, whether the helix will exist in the A-form or in the B-form. So, in C2-endo puckering occurs in B-form of DNA. ​

    Correct Option: B

    ​Nitrogenous bases are always arranged in "anti" positions to their corresponding pentose sugar moieties. In B-form of DNA, sugar puckering occurs predominantly in the C2 position of the pentose sugar. The sugar pucker determines the shape of the a-helix, whether the helix will exist in the A-form or in the B-form. So, in C2-endo puckering occurs in B-form of DNA. ​

  1. ​If a plant is shifted to cold temperature, which of the following changes would take place in its membrane? ​​








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    When a plant body is shifted from a warm climate to a cold climate, the number of long chain unsaturated fatty acids present in the plant would increase to preserve and store body heat as well as reserved energy. So, ratio of unsaturated to saturated fatty acids would increase considerably in that plant. ​

    Correct Option: A

    When a plant body is shifted from a warm climate to a cold climate, the number of long chain unsaturated fatty acids present in the plant would increase to preserve and store body heat as well as reserved energy. So, ratio of unsaturated to saturated fatty acids would increase considerably in that plant. ​

  1. Amino acid residue which is most likely to be found in the interior of water-soluble globular proteins is ​








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    Globular proteins have no systematic structures. There may be single chains, two or more chains which interact in the usual ways or there may be portions of the chains with helical structures, pleated structures, or completely random structures. Common globular proteins include egg albumin, hemoglobin, myoglobin, insulin, serum globulins in blood, and many enzymes. Water-soluble globular proteins have hydrophobic amino acids present in the interior of the protein structure forming hydrophobic bonds. So, valine is the amino acid residue most likely to be present on the interior.

    Correct Option: C

    Globular proteins have no systematic structures. There may be single chains, two or more chains which interact in the usual ways or there may be portions of the chains with helical structures, pleated structures, or completely random structures. Common globular proteins include egg albumin, hemoglobin, myoglobin, insulin, serum globulins in blood, and many enzymes. Water-soluble globular proteins have hydrophobic amino acids present in the interior of the protein structure forming hydrophobic bonds. So, valine is the amino acid residue most likely to be present on the interior.

  1. The 4-amino or 4-keto group of pyrimidine bases is located in the ​​








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    ​The pyrimidine bases, Thymine and Cytosine in case of DNA have a 4-amino or a 4-keto group present with the amide ring. These 4-amino or 4-keto groups are present in the major groove of the DNA molecule.

    Correct Option: A

    ​The pyrimidine bases, Thymine and Cytosine in case of DNA have a 4-amino or a 4-keto group present with the amide ring. These 4-amino or 4-keto groups are present in the major groove of the DNA molecule.