Which one of the following cellular parts is correctly described?

Options

(a) Centrioles – Sites for active RNA synthesis
(b) Lysosomes – Optimally active at a pH of about 8.5
(c) Thylakoids – Flattened membranous sacs forming the grana of chloroplasts
(d) Ribosomes – Those on chloroplasts are larger (80S) while those in the cytoplasm are smaller (70S)

Correct Answer:

Thylakoids – Flattened membranous sacs forming the grana of chloroplasts

Explanation:

Centrioles serve as basal bodies for cilia and flagella. They are concerned with spindle formation during cell division. Lysosomes are membrane-bound organelles containing many hydrolytic enzymes, which are optimally active at an acid pH (near pH 5). Thylakoids are membrane-bound organelles found within chloroplasts. The thylakoid membrane, forms many flattened, fluid-filled tubules that enclose a single convoluted compartment. These tubules tend to stack on top of each other to forma structure called a granum.