Although a prokaryotic cell has no defined nucleus, yet DNA is not scattered throughout the cell. Explain.
The DNA (negatively charged) is scattered in the cytoplasm means that it is naked and is not covered by any membrane. The prokaryotes use an arrangement that helps to pack genetic material tightly into a specific region known as nucleoid because prokaryote does not have a well-defined nucleus. So DNA is not scattered but present in the form of a membrane-less structure called nucleoid.
This nucleoid floats in the cytoplasm and can be found anywhere in the cytoplasm. Also, the DNA in form of single chromosomes is attached to mesosome at a point.
Explain the mechanism of ‘sex determination’ in birds. How does it differ from that of human beings?
Write the difference between genetic biodiversity and species biodiversity that exists at all the levels of biological organisation.
“India has greater ecosystem diversity than Norway.” Do you agree with the statement? Give reasons in support of your answer.
With the help of an algebraic equation, how did Hardy-Weinberg explain that in a given population the frequency of occurrence of alleles of a gene is supposed to remain the same through generations?
How has the use of Agrobacterium as vectors helped in controlling Meloidogyne incognita infestation in tobacco plants? Explain in the correct sequence.
Organic farmers prefer the biological control of diseases and pests of the use of chemicals for the same purpose. Justify.
Select and write analogous structures from the list given below:
(i) Wings of butterfly and birds
(ii) Vertebrate hearts
(ii) Tendrils of bougainvillaea and Cucurbita
(iv) Tubers of sweet potato and potato
