(1) Lamellar model
(3) Fluid mosaic model
"Protein icebergs in a sea of lipid" means
(1) Unit membrane concept
(3) Fluid mosaic model
Answers
Explanation:
Cell: The Unit of Life
10.2
1. Introduction
There is a huge diversity in all the organisms on the earth as studied in previous unit. Four million organisms
are present on earth including all the phylum and divisions. All these organisms have biological diversity in
terms of size, shape, structure and even functions.
Yet there are similarity among them in few of the basic functions. All living organisms are made up of a
common basic unit. After various research and study in this concept, scientist concluded that the basic
unit is the cell. The cell is a unit which makes, performs and activates several functions and activities of the
organism. Thus, they are termed as the basic functional and structural unit of the cell.
The cell is separated from the surrounding environment through a membrane. The cell has several functions,
abilities and organelles in it. This function and ability changes as the position or the organism changes.
Also the cell number changes per organism which is why some organisms are unicellular and some
multicellular. In unicellular organisms the cell performs all the functions and work of the organisms while in
multicellular one it is well developed and divided among the organisms body.
Objectives of the chapter
At the end of this chapter you will be able to:
y Elaborate a cell and its uniqueness.
y Differentiate a cell as prokaryote or eukaryote.
y Explain different cell organelles.
2. A Cell – What is it all about?
A cell is a structure made up of several small units called organelles,
chemicals, molecules and liquids. These all constituents are present in
it and work in a way to complete a particular function. The cell shape,
size and the constituents vary as per its position and function.
Cell defines an organism’s existence and its functions. Hence it is
called structural and functional unit of all the living organisms.
Lowey and Sikewitz defined a cell as “the unit of biological activity
container and nucleus that has the ability to reproduce or divide in a
medium free from other living organisms.
Cytology ⇒ The science dedicated to the Study of Cell Structure.
Cell biology ⇒ The Study of all the structures and functions along with the reproduction of
the cell.
Figure 10.1: Diagram of a cell