KVPY Sample Paper KVPY Stream-SX Model Paper-16

  • question_answer
    Assuming that histone octamer forms a cylinder 9 nm in diameter and 5 nm in height and that the human gemone forms 32 million nucleosomes, what fraction (approximately) of the volume of nucleus (6 \[\mu \]m diameter) is occupied by histone octamers?

    A) \[1/21\]

    B) \[1/11\]

    C) \[10/21\]

    D) \[10/11\]

    Correct Answer: B

    Solution :

    Radius of histone octamer (r) =4.5 nm
    Height of histone octamer (h) = 5 nm
    Volume of one histone octamer = \[\pi {{\operatorname{r}}^{2}}h\]
    \[=\frac{22}{7}\times 4.5\times 4.5\times 5\]\[=318.214n{{m}^{3}}\]\[=318.214\times 1{{0}^{-27}}{{m}^{3}}\]
    Total volume of histone octamers present in human genome\[=318.214\times {{10}^{-27}}{{\operatorname{m}}^{3}}\times 32\times {{10}^{6}}\]
    \[=10182.85\times 1{{0}^{-21}}{{m}^{3}}\]
    Radius of nucleus \[=3\mu \operatorname{m}=3\times {{10}^{-6}}nm\]
    Volume of nucleus \[=\frac{4}{3}\pi {{\operatorname{r}}^{3}}\]\[=\frac{4}{3}\times \frac{22}{7}\times 3\times {{10}^{-6}}\times 3\times {{10}^{-6}}\times 3\times {{10}^{-6}}\]\[=113.14\times {{10}^{-18}}\]
    Fraction of the volume of nucleus occupied by histone octamers \[\frac{10182.85\times {{10}^{-21}}}{113.14\times {{10}^{-18}}}\]\[=0.09\approx 1/11\]


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