Cell Biology Test - 8

Discoidal shaped nucleus is found in the cells of squamous epithelium. Spherical nucleus is found in isodiametrical cells. Ellipsoid nucleus is found in fusiform cells.

Sphaerosome is an organelle which synthesises and stores lipids, besides smooth endoplasmic reticulum. These are the smallest, single membrane bound, spherical organelles of the cell.

The main function of the nucleoplasm is to serve as a suspension substance for the organelles inside the nucleus. It also helps maintain the shape and structure of the nucleus, and plays an important role in the transportation of materials that are vital to cell metabolism and function.

The nucleolus does not contain euchromatin. This is the light stained region of chromatin.

Intermediate filaments (IFs) are tough and durable protein fibers in the cytoplasm of higher eukaryotic cells. In most animal cells, IFs form a 'basket' around the nucleus and extended out in gentle curving array to the cell periphery. They are constructed like woven ropes and provide tensile strength for the cell.

Leeuwenhoek was the first to observe, describe and sketch a free living cell.

The shape of Spirillum bacteria is coiled like a cork-screw. Many spirilla are rigid and capable of movement. A special group of spirilla known as spirochetes are long, slender, and flexible.

This is the correct option as this is a property of Gram-negative bacteria. The wall is two layered.Outer membrane is present.The lipid content of the wall in Gram-negative bacteria is 20-30%. The lipid content of the wall is quite low in Gram-positive bacteria.The wall of a Gram-negative bacterium is wavy and comes in contact with plasmalemma only at a few places.Four rings of swellings occur in the basal body of Gram-negative bacteria. Basal body of the flagellum has two rings of swellings in Gram-positive bacteria.

This is the correct option as statement 'a' is false. Chromatophores are internal membrane systems of photosynthetic forms which possess photosynthetic pigments.

Golgi apparatus is responsible for the formation of lysosomes. A major function is the modifying, sorting and packaging of proteins for secretion. It is also involved in the transport of lipids around the cell.