Test: Cell Structure & Functions- 1 - UPSC

A tissue is a group of cells, in close proximity, organized to perform one or more specific functions.

There are four basic tissue types defined by their morphology and function:
(i) Epithelial tissue
(ii) Connective tissue
(iii) Muscle tissue
(iv) Nervous tissue

Those organisms that are made up of only one cell are called unicellular organisms.
Example: Amoeba, Paramecium, Bacteria.

Amoeba have pseudopodia, which are projections of varying lengths protruding out of its body. Amoeba does not have a regular shape and uses pseudopodia for locomotion and digestion.

Cells are the functional and structural units of living organisms. They are capable of performing respiration, synthesis, and digestion of food to obtain energy.

The cell was first discovered and named by Robert Hooke in 1665.
However, Hooke actually saw was the dead cell walls of plant cells (cork) as they appeared under the microscope. Hooke's description of these cells was published in Micrographia.

Mitochondria are tiny organelles inside cells that are involved in releasing energy from food. This process is known as cellular respiration. Due to which they are referred to as the powerhouses of the cell.

(i) Ribosomes can be found floating within the cytoplasm
(ii) Nucleus is present in the cell.
(iii) Chloroplasts are present in the cytoplasm of plant cells.
(iv) Nuclear membrane surrounds the nucleus and cell membrane surrounds the cell.

Thus option B is correct.

The cell present in our body that can change its shape is Red Blood Cell and White Blood cell.
As they move through narrow blood vessels and they can change their shape to improve locomotion.

Nervous system contains millions of nerve cells, called neurons. Neurons are highly specialised to transmit messages from one part of your body to another. All neurons have a cell body and one or more fibres.

The nucleus contains thread-like structures called chromatins. Condensed forms of chromatin are known as chromosomes.
During cell division, these chromosomes carry genes and help in the transfer of characters from parents to offspring.