Cell Structure exercise (liveworksheets.com)
Cell Structure and Functions
When viewing a specimen through a light microscope, scientists use ________ to
distinguish the individual components of cells.
A.
B.
C.
D.
a beam of electrons
radioactive isotopes
special stains
high temperatures
The ________ is the basic unit of life.
A.
B.
C.
D.
organism
cell
tissue
organ
Prokaryotes depend on ________ to obtain some materials and to get rid of wastes.
A.
B.
C.
D.
ribosomes
flagella
cell division
diffusion
Every organ in our body performs a variety of different functions such
as digestion, assimilation, and absorption. Similarly, in the plants too, there are
different organs of the plant which performs specialized or specific functions. For
instance, the roots of the plants help in the absorption of minerals and water.
In our body and in the body of every living organism, every organ is composed of
smaller parts known as tissues. A tissue is a group of like cells that perform a specific
function. Let’s learn more about the cell structure and functions.
Cell Membrane
One of the most important parts of the cell is the cell membrane. The cell membrane
acts as a semi-permeable barrier. It allows only a few molecules across it and fences
the majority of organically produced chemicals inside the cell.
The primary components of the cell are – cell membrane, nucleus, and cytoplasm.
The nucleus and cytoplasm are enclosed within the cell membrane that is also known
as the plasma membrane. It works to separate cells from one another and also the cell
from the surrounding medium. The plasma membrane is porous and allows the
movements of materials or substances both inward and outward.
Cell membrane offers shape and rigidity to the cell. In the case of the plant cells,
besides the cell membrane, there is also an outer thick layer that is known as the cell
wall. This additional layer which surrounds the cell membrane is necessary for
offering the requisite protection to the plants.
The cells of the plants need protection against the variations in temperature, high
wind speed, atmospheric moisture, etc. The plants are exposed to variations since
they cannot move. You can easily observe the cells in the lead peel
of Rhoeo, Tradescantia or Elodea.
Cytoplasm
Another important part of the cell is the cytoplasm. It is a jelly-like substance that is
present between the nucleus and the cell membrane. There are a number of other
components or organelles of the cell that can be found in the cytoplasm. These
are mitochondria, Golgi bodies, ribosomes, etc.
Exercise 1. Put the definitions to the right order