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NEET-XII-Biology

Percentage Booster year:2024 Set:28

 
  • #1
    Explain the composition of triglyceride.
    Ans : Triglyceride is a glyceride, which is formed from a single molecule of glycerol, esterified with three fatty acids. It is mainly present in vegetable oils and animal fat.



    Structure of triglyceride

    The general chemical formula of triglyceride is , where R1, R2, and R3 are fatty acids. These three fatty acids can be same or different.
  • #2
    Can you describe what happens when milk is converted into curd or yoghurt from your understanding of proteins.
    Ans : Proteins are macromolecules formed by the polymerization of amino acids. Structurally, proteins are divided into four levels.

    (a) Primary structure - It is the linear sequence of amino acids in a polypeptide chain.

    (b) Secondary structure - The polypeptide chain is coiled to form a three-dimensional structure.

    (c) Tertiary structure - The helical polypeptide chain is further coiled and folded to form a complex structure.

    (d) Quaternary structure - More than one polypeptide chains assemble to form the quaternary structure.

    Milk has many globular proteins. When milk is converted into curd or yoghurt, these complex proteins get denatured, thus converting globular proteins into fibrous proteins. Therefore, by the process of denaturation, the secondary and tertiary structures of proteins are destroyed.
  • #3
    Asymptote in a logistic growth curve is obtained when :
    (1) K < N
    (2) The value of 'r' approaches zero
    (3) K = N
    (4) K > N
    digAnsr:   3
    Ans : (3)
    Sol.
    K = N
    When K (Carrying capacity) equals to N (Population Density) the logistic growth acquire steady or
    asymptote stage
  • #4
    The association of histone H1 with a nucleosome indicates :
    (1) The DNA double helix is exposed
    (2) Transcription is occurring
    (3) DNA replication is occurring
    (4) The DNA is condensed into a Chromatin Fibre
    digAnsr:   4
    Ans : (4)
    Sol.
    During DNA condensation into a chromatin fibre the DNA wraps around histone octamer and H1 Histone
    works as clip to prevent unwraping of DNA
  • #5
    Homozygous purelines in cattle can be obtained by :
    (1) mating of individuals of different species
    (2) mating of related individuals of same breed
    (3) mating of unrelated individuals of same breed
    (4) mating of individuals of different breed
    digAnsr:   2
    Ans : (2)
  • #6
    Mycorrhizae are the example of :
    (1) Mutualism
    (2) Fungistasis
    (3) Amensalism
    (4) Antibiosis
    digAnsr:   1
    Ans : (1)
    Sol. Mycorrhiza is mutualistic interaction between algae & fungi
  • #7
    A baby boy aged two years is admitted to play
    school and passes through a dental check-up. The dentist
    observed that the boy had twenty teeth. Which teeth were absent ?
    (1) Molars
    (2) Incisors
    (3) Canines
    (4) Pre-molars
    digAnsr:   4
    Ans : (4)
    Sol. Premolar teeth are absent in child who bears only milk teeth.