Cell The Unit of Life Test - 8

Histone proteins are the basic packer and arranger of chromatin.

Animal cells have centrioles which are absent in almost all plant cells.

Several ribosomes may attach to a single mRNA and form a chain called polyribosomes or polysome. The ribosomes of a polysome translate the mRNA into proteins.

The middle lamella is a layer mainly of calcium pectate which holds or glues the different neighbouring cells together.

The cell wall and middle lamellae may be traversed by plasmodesmata which connect the cytoplasm of neighbouring cells by forming mitotic plates.

The German doctor Rudolf Virchow proposed in 1855 that all cells result from the division of previously existing cells, and this idea became a key piece of modern cell theory.

The cytoskeleton in a cell is involved in functions like mechanical support, motility, maintenance of the shape of the cell.

Mitochondria are the sites of aerobic respiration. They produce cellular energy in the form of ATP

Lysosomes are single membrane structures containing enzymes for digestion of all types of macromolecules.

In plant cells, the chloroplasts are responsible for trapping light energy essential for photosynthesis. The grana, in the plastid, is the site of light reactions.