Science M.C.Q. [I MARKS]

The cells having well defined nucleus containing nuclear material, enclosed by a nuclear membrane are called eukaryotic cells.
e.g. Cheek cells. Blue-green algae are prokaryotic cells that do not have a nuclear membrane.

Epithelial tissue forms the outer protective covering all over the body and also lines body cavities.

An amoeba cell and white blood cell present in human blood can change their shape.

Cell wall is a characteristics of plant cell only and absent in animal cell. It is an outer, rigid, protective and supportive covering of plant cells. The cell wall lies outside of the plasma membrane. Epidermal cell and mesophyll cell are examples of plant cells. Thus, they have cell wall.

A microscope is an optical instrument used to observe objects that are invisible to the naked eye. It is used to view and study cell structure. The science of viewing small objects using a microscope is called microscopy.

A unicellular organism consists of a single cell that is capable of performing all the functions. The other statements in true form are:
Cells cannot be seen easily with naked eyes.
Insect’s egg is a single cell.
The shape and size of cell are different in multicellular organisms.

The iris of the eye, uterus and bronchi contain smooth muscles.

Connective tissue give support to the body, and defends with pathogens and stores food in the body.

Nucleus is called the 'control room' or 'brain' of the cell because it controls all the functions of the cell.

Organisms which do not have true nucleus are called prokaryotes. Bacteria and blue green algae are examples of prokaryotes.

Cell staining is the technique of colouring different cellular organelles. It is used to visualise cells and cellular components better under a microscope. By using different stains, one can preferentially stain specific cell components, such as a nucleus, cell wall, or the entire cell.

Cytoplasm is the transparent jelly like fluid which fills the cell between nucleus and cell membrane. Most of the chemical reactions which keep the cell alive takes place here.Protoplasm is the living substance of the cell. It includes the cytoplasm and nucleus. Chromoplasts are coloured plastids present in plant cell.Chromosomes are thread-like structures present in nucleus.

Golgi body helps in the secretion of substances like enzymes, it helps in the proper metabolic functioning of the cell.

Most of the cells are microscopic in size and are not visible to the unaided eye. They need to be enlarged or magnified by a microscope. Some cells are big enough to be seen with the unaided eye. Example of that is a hen’s egg which is considered as a single cell. It can be seen by the naked eye.

Red blood cell does not have a nucleus.

The non-living part of a tomato cell is its cell wall. Cell wall is the outer most covering of a plant cell. It is a non-living and rigid.

The correct combination of terms with reference to an animal cell is cell membrane, mitochondria, ribosome and chromosome. An animal cell does not have a cell wall, plastid and chloroplast, but these are present in plant cells.