Cell The Unit Of Life

Lampbrush chromosomes were first observed by Flemming (1882), but were first described by Ruckert (1892). These chromosomes occur in the diplotene stage of meiotic prophase-I during oogenesis in amphibian oocytes. The chromosomes are highly elongated special kind of synapsed midprophase or diplotene chromosome bivalents (i.e. two pairs of sister chromatids held together by" chiasmata). These chromosomes are larger than even polytene chromosomes. In lampbrush chromosome, the strands of chromosome ( consisting of two double strands of DNA) are dotted with about 5000 chromomeres (dark staining irregular structures).Twin loops emerge from chromomeres. These loops are identical on both pairs of sister chromatids.

Chloroplasts are greenish plastids which possess photosynthetic pigments, chlorophyis (5-10%) and carotenoids viz. carotenes and xanthophylls (1-2%) and take part in the synthesis of food from inorganic raw materials in the presence of radiation energy. They do not have anthocyanin.

Apoptosis is programmed cell death which is mediated through selective activation of endogenous endonucleases, which result in cleavage of chromatin at regularly spaced sites

The enzyme called peptidyl transferase, an integral part of the large ribosomal subunit, transfers the fMet from its tRNA in the P site to the aminoacyl-tRNA in the A site. This forms a two amino acid unit called dipeptide linked to the tRNA in the A site.

Answer (b) Cell wall