Cells and Organelles

Question 1

Define cell

Answer 1

Semi indepedent living unit within the body in which are sited the mechanisms for metabolism, growth and replication. Consists of an aqueous solution of organic molecules surrounded by a membrane.

Question 2

Define organelle

Answer 2

Subunit within a cell with a defined structure and performing specific integrated activities.
Some are bound by membranes.

Question 3

Define tissue

Answer 3

Organised assembly of cells and their extracellular products which carry out similar and coordinated activities within the body.

Question 4

Organ

Answer 4

Assembly of tissues coordinated to perform specific functions within the body.

Question 5

System

Answer 5

Assembly of organs with specific, related activities sharing regulatory influences. OR it may be a diffuse functional network of cells situated in many parts of the body, sharing specific activities.

Question 6

Define prokaryote

Answer 6

Single celled organism in which the chromosome is a circular strong lying free in the cell and has no membranous organelles

Question 7

Define eukaryote

Answer 7

One or more cells in which chromosomes are enclosed in a nucleus; typically has cytoplasmic membrane-bound organelles, DNA divided into a series of linear chromosomes and considerable difference occur between cells within the same organism.

Question 8

Define virus

Answer 8

An assemblage of nucleic acid (DNA or RNA) and proteins which is parasitic on prokaryotes/eukaryotes. Viruses invade cells, subvert their protein synthesis machinery to make more viruses instead of normal cell proteins, then escape to infect other cells.
Viruses are not cells or organisms as they can only reproduce via a host cell.