Cell The Unit Of Life

Answer (b) Basic proteins

Answer (a) Active process

To maintain their internal acidic pH, lysosomes must actively concentrate ions (protons). This is accomplished by a proton pump in the lysosomal membrane, which actively transports protons into the lysosome from the cytosol. This pumping requires expenditure of energy in the form of ATP hydrolysis, since it maintains approximately a hundred-fold higher concentration inside the lysosome.

Protein synthesis occurs in cytoplasm where the ribosomes are located. According to the sequence on DNA mRNA is synthesised in nucleus. After formation, mRNA leaves nucleus and produces protein on binding with ribosomes according to the cell?s needs.

A chloroplast is a vesicle bounded by an envelope of two unit membranes and filled with a fluid ; matrix called stroma. The lamellae, after separation from the inner membrane, usually take the form of closed, flattened, ovoid sacs, the thylakoids, which lie closely packed in piles, the grana. The thylakoid membrane contains photosynthetic pigments namely, chlorophyll a, chlorophyll b, carotenoids (carotene, xanthophylls) and plastoquinone. The thylakoid membranes also contain : coupling factors that bring about ATP synthesis.