This document provides an overview of cells. It begins by defining a cell as the fundamental unit of life and describes how Robert Hooke first observed cells in cork through a microscope in 1665. It then discusses the main instruments used for studying cells - light microscopes and electron microscopes. The document outlines the key differences between plant and animal cells and describes some of the main cell organelles like the cell wall, nucleus, chloroplasts, and mitochondria. It provides comparisons between different types of cells and cell components.

1. THE FUNDAMENTAL
UNIT OF LIFE: CELL
• By Sujal Kumar CLASS 9A

2. CONTENTS OF THIS PRESENTATION:
Here’s what you will find in this presentation;
 What is a cell?
 Discovery of cell?
 Instruments for studying cells?
 Types of cells and their gradual evolution?
 Differences between or distinguish between?
 Some amazing fact about cell!

3. WHAT IS A CELL?
• A cell is the structural and fundamental unit of
life.
• The study of cells from its basic structure to the
functions of every cell organelle is called CELL
BIOLOGY.

4. • DISCOVERY OF CELL?
 While studying a thin slice of cork, ROBERT
HOOKE saw that the cork resembled the
structure of honeycomb consisting of many little
compartments.
Cork is a substance which is obtained from bank
of tree.
This was in the year 1665 when Hooke made this
chance discovery through a self designed
microscope, ROBERT HOOKE called these
bokes-cells.
Robert Hooke discovery was important, because
it indicated for the first time that living
organisms consisted of a number of smaller
structures or units.

5. INSTRUMENTS FOR STUDYING CELL’S?
 Light microscope
1. It uses glass lenses.
2. It uses a beam of light to illuminate
the object.
3. Internal vacuum is not required.
Electron microscope
1) It uses electromagnets.
2) It uses a beam of electrons instead of
light.
3) Internal vacuum I essential.

6. SOME PICTURE OF LIGHT AND
ELECTRON MICROSCOPE.
• LIGHT MICROSCPE o ELECTRON MICROSCOPE

7. How many types of cell are there?
 There are two types of cell:
1. Plant cell
2. Animal cell

8. WHAT IS ANIMAL CELL?
An animal cell are type of
eukaryotic cell that lacks a
cell wall and has a true,
membrane-bound nucleus
along with other cellular
organelles.

9. WHAT IS PLANT
CELL?
 Plant cell are the basic unit
of life in organisms of the
kingdom plantae.
 They are eukaryotic cells,
which have a true nucleus
along with specialized
structure called organelles
that carry out different
functions.
 Plant cells have special
organelles called
chloroplast, which create
sugars via photosynthesis.

10. 2.) EUKARYOTIC CELL
Size of a cell is generally large (5-100
mm).
Nucleas is present (Nuclear material is
surrounded by a nuclear membrane).
It contains more than one chromosome.
Nucleolus is present.
Membrane bound cell organelles such as
mitochondrion plastids, endoplasmic
reticulum, Golgi apparatus lusosomes,
peroxisomes, etc., are present.
Cell division occurs by mitotic or meiotic
cell division.

11. Let us study some more
type of cells.
1. Prokaryotic cell
 Size of cell is generally small (1-10 mm).
 Nucleus is absent (Nuclear region or
nucleoid is not surrounded by a nuclear
membrane).
 It contains single chromosome.
 Nucleolus is absent.
 Membrane bound cell organelles are
absent.
 Cell division takes place by fission of
budding (no mitosis).

12. 1.)DIFFERENCE BETWEEN NUCLEUS AND NUCLEOID
NUCLEUS
o It is larger in size.
o It has a covering of double membrane envelop.
o Nucleolus is present in it.
o Its DNA content is equal to two several DNA
molecules.
o Its DNA is associated with histone proteins to from
chromatin.
NUCLEOID
• It is comparatively smaller in size.
• A covering membrane is absent. It lies
free in the cytoplasm.
• Nucleolus is absent in it.
• Its DNA content is equal to a single DNA
molecule.
• In it histones are absent. DNA of a
nucleoid is often naked.

13. 2.) Differences between organs and organelles
ORGANS
 They are found in multicellular
organisms.
 They may be external or internal to
the body of an organisms.
 An organs are formed of tissues,
tissues comprise cells and cell are
formed of organelles.
 Organs coordinate to from organs
systems, while organs systems from
the body of an organisms.
ORGANELLES
 They are found in all eukaryotic
cells.
 They are very small sized, either
microscopic or submicroscopic.
 They are mostly internal.
 An organelle is made up of
micromolecules and
macromolecules.
 Organelles coordinate to protect
the cell.

14.  CELL ORGANELLES AND INCLUSIONS
A. Living parts of a cell
1. Plasma membrane
2. Cytoplasm
 Endoplasmic reticulum (ER)
a. Smooth ER
b. Rough ER
 Mitochondria
 Golgi apparatus
 Ribosomes
 lysosomes
 Centrioles (animals only)
 Plastids (plants only)
3. Nucleus
B. Non-living parts of a cell
1. Cell wall (plant only)
2. Vacuoles
3. Granules (cell inclusions)

15. 3. DIFFERENCES BETWEEN DIFFUSION AND OSMOSIS?
DIFFUSION
 Diffusion can occur in any medium.
 The diffusing molecules may be solids,
liquids, gasws.
 Semipermeable membrane is not required.
 It is dependent upon the free energy for
the molecules of diffusing substances only;
presence of other substances in the system
is of no importance.
 An equiblibrium in the free energy of
diffusion molecules is achieved in the
system.
OSMOSIS
 It occurs only in liquid medium.
 It involves movement of solid molecules.
 Semipermeable membrane is required.
 Though it is the diffusion of solvent
molecules only yet influenced by the
presence of other substances (solutes) in
the system.
 Equilibrium in the free energy of solvent
molecules is never achieved.

16. 4.) DIFFERENCES BETWEEN ACTIVETRANSPORT
AND DIFFUSION?
ACTIVE TRANSPORT
 It is a rapid process.
 It can moves materials through a
biological (cellular) membrane against
the concentration gradient.
 It takes place in one direction only.
 It needs carrier (or transport) proteins to
occurs.
 It uses energy of ATP.
It brings about selective uptake of
materials.
It leads to accumulation of materials in
the cell.
DIFFUSION
o It is a slow process.
o It can move materials across a bio
membrane down the concentration
gradient.
o It takes place in both direction.
o It occurs without the help of carrier
proteins.
o It does not use energy.
o It allows all transmissible molecules to
pass through membrane.
o it does not accumulate materials in the
cell.

17. 5.) DIFFERENCES BETWEEN ENDOCYTOSIS AND
PHAGOCYTOSIS?
ENDOCYTOSIS
i. It is the intake fluid, droplets and
macromolecules.
ii. Plasma membrane invaginates to
take up the material.
iii. It is nutritive process.
iv. Endocytosis vesicles are only 0.1
um wide.
PHAGOCYTOSIS
i. It is the intake of extracellular
particles.
ii. Plasma membrane grows around
the particle as pseudopodia.
iii. It is a nutritive and a defensive
process.
iv. Phagocytosis vesicles are 1 to 2
um or more wide.

18. CELLWALL

19. NUCLEOLUS

20. Chemical
1) Oxygen
2) Carbon
3) Hydrogen
4) Nitrogen
5) Trace elements (Ca/ P, Cl, S,
K, Na, Mg, I, FE)
PERCENTAGE
64.00
18.00
10.00
0.3.00
0.5.00

21. Rough Endoplasmic Reticulum
1) It contains flattened sacs called
cisternae.
2) Ribosomes are attached to the outer
surface of its membrane.
3) It is specialized to synthesize proteins.
4) It is abundant in exocrine pancreatic cells
and antibodies secreting plasma cells.
Smooth Endoplasmic Reticulum
1) It is mainly formed of vesicles and
tubules.
2) It does not contain ribosomes.
3) It is specialized to synthesize lipids and
steroids.
4) It is abundant in liver and the testicular
cells (e.g., Leydig cells) synthesizing
steroid hormones.

22. 10.) DIFFERENCES BETWEEN CHLOROPLASTS
AND CHROMOPLASTS?
CHLOROPLASTS
 They are green plastids.
 They contain chlorophylls and
carotenoids.
 Lamellae are present.
 Chloroplasts are sites of
photosynthesis.
CHROMOPLASTS
 They are non-green colour plastids.
 Chlorophylls are absent. Only
carotenoids.
 Lamellae are absent.
 They add colour to the organs (e.g.,
flowers, fruits) for attracting animals to
perform pollination and fruits dispersal.

23. 11.) DIFFERENCES BETWEEN MITOCHONDRIA AND
CHLOROPLASTS?
MITOCHONDRIA
 They occurs in the cells of aerobic organisms
(plants and animals) with the exception of
mammalian RBCs.
 They are colourless.
 The shape is rod-like or sausage-shaped.
 Inner membrane of each mitochondrion is
thrown into folds called cristae.
 They liberate energy.
 They perform oxidation of food.
 They consumes oxygen and liberate carbon-
dioxide
CHLOROPLASTS
 They occurs in the cells of green
photosynthetic parts (e.g., leaves) of plants.
 They are green in colour.
 They are generally dics-like in outline.
 Their inner membrane forms flattened sacs
called thylakoids or lamrllae.
 Thry trap solar energy and convert it into
chemical energy.
 They synthesize food by photosynthesis.
 They consume carbon-dioxide and liberate
oxygen.

26. Thank you