The document discusses cells and their components. It defines cells as the basic unit of structure and function of living things. It describes several key organelles and their functions, including the nucleus, mitochondria, chloroplasts, endoplasmic reticulum, Golgi complex, lysosomes, vacuoles, and plasma membrane. It also distinguishes between prokaryotic and eukaryotic cells, noting that prokaryotes are smaller and lack a nucleus while eukaryotes have membrane-bound organelles and nuclei.

5. Contents
 Cell
 Cell theory
 Cell organelles and their functions
 Types of cell

6. Cell
Cell: A cell is a basic unit of structure and
function of life. In other words, cells make
up living things and carry out activities
that keep a living thing alive. We can find
cells almost anywhere on earth e.g.:- In
the air, inside us, plants etc.

7. Continue…..
 What makes a cell?
 A cell is a living thing.
 Cells are able to make more cells like
themselves.
 New cells can only come from existing
cells (cells that are already existing).

8. Microscope used by
Robert Hooke

9. The cell theory
 All organisms are made of one or more
cells
 The cell is the basic unit of all living things
 All cells come from pre-existing cells

10. Cell organelles and their
functions
Mitochondria
 It has double membrane organelle
central cavity is filled with matrix
 inner membrane folds known as cristae
Functions-
 generation of ATP
 “powerhouse of cell”
 Mitochondria self-replicate
increases with need for ATP

11.  Nucleus- The nucleus is the control center of the cell. It is
the largest organelle in the cell and it contains the DNA of
the cell. The DNA of all cells is made up of chromosomes.

 DNA (Deoxyribonucleic Acid) contains all the information
for cells to live, perform their functions and reproduce.
 Inside the nucleus is another organelle called the
nucleolus. The nucleolus is responsible for making ribosome.
 The circles on the surface of the nucleus are the nuclear
pores. These are where ribosome, and other materials
move in and out of the cell.

12.  Plastids- they are of three kinds-
1.chloroplast-helps to make food for the
plant by photosynthesis.
2.chromoplast-gives color to the some
parts of plants like
flowers
3.leucoplasts-store food

13.  Ribosome- Organelles that help in the synthesis of proteins.
Ribosome are made up of two parts, called subunits.
They get their names from their size. One unit is larger than
the other so they are called large and small subunits.
Both these subunits are necessary for protein synthesis in the
cell. When the two units are docked together with a special
information unit called messenger RNA, they make
proteins.
Some ribosome are found in the cytoplasm, but most are
attached to the endoplasmic reticulum. While attached to
the ER, ribosome make proteins that the cell needs and
also ones to be exported from the cell for work elsewhere in
the body.

14.  Endoplasmic reticulum (ER)- It is a network of
membranes throughout the cytoplasm of the
cell. There are two types of ER.
 When ribosome are attached it is called
rough ER and smooth ER when there are no
ribosome attached.
 The rough endoplasmic reticulum is where
most protein synthesis occurs in the cell. The
function of the smooth endoplasmic reticulum
is to synthesize lipids in the cell. The smooth ER
is also helps in the detoxification of harmful
substances in the cell.

16.  Golgi complex- It is organelle in
the cell that is responsible for
sorting and correctly shipping
the proteins produced in the
ER.
 Just like our postal packages
which should have a correct
shipping address, the proteins
produced in the ER, should be
correctly sent to their
respective address.
 In the cell, shipping and sorting
done by the Golgi complex. It is
a very important step in protein
synthesis.
 If the Golgi complex makes a
mistake in shipping the proteins
to the right address, certain
functions in the cell may stop.

17. • Lysosomes-
• They are Membranous
vesicles and formed in
Golgi complex
• They are filled with digestive
enzymes and pump in H+
ions until internal pH
reaches 5.0
• Functions -
• digest foreign substances
• autophagy (recycles own
organelles)
• Autolysis(Lysosomal
digestion of the cell after
death)

18.  Steps in lysomal formation
(1) The ER and Golgi apparatus make a lysosome
(2) (2) The lysosome fuses with a digestive vacuole
(3) Activated acid
(3) hydrolases digest the contents

19.  Cilia are thread-like projections of certain cells
that beat in a regular fashion to create currents
that sweep materials.

20. • Vacuoles-These are fluid-filled structures
used to store different substances and
help in osmo-regulation. In animal cells
there are often many small vacuoles.
Plants have large vacuoles.

21. Vesicles- This term literally means "small
vessel". This organelle helps store and
transport products produced by the cell.
The vesicles are the transport and delivery
vehicles like our mail and Federal Express
trucks. Some vesicles deliver materials to
parts of the cell and others transport
materials outside the cell in a process
called exocytosis.

22.  Plasma membrane: The plasma
membrane surrounds the cell. It regulates
the movement of substances in or out of
the cell. It is made up of a lipid and
protein bi-layer. Think of the membrane as
a gatekeeper, it only allows some
materials to pass through, but keeps
others out.
 Cytoplasm: This is a gel-like fluid, that
takes up most of the space inside a cell.
Cytoplasm kind of looks like jelly.

27. Types of cell:-
 Prokaryotic cells-
E.g.:-Bacteria
 Eukaryotic cells-
Unicellular
E.g.:-Protists
Multi-cellular
E.g.:-Fungi, Plants, Animals

28.  Prokaryotes – the meaning of their name
is pro-primitive karyon-nucleus.
 They are small in size and they don’t have
a properly arranged nucleus.
 They have single chromosome.
 Nucleolus is also absent.
 Generally they are pathogens.
 They have circular or coiled DNA

30.  Eukaryotes – the meaning of their name is
eu- developed karyon-nucleus.
 It has membrane bound nucleus.
 It contains many organelles.
 It has linear DNA.
 Membrane bound organelles are present.
 They have more than 1 chromosome

32. Feature Prokaryote Eukaryote
Size
Small about 0.5
micrometers
Up to 40 micrometers
Genetic
material
Circular DNA (in
cytoplasm)
DNA in form of linear
chromosomes ( in nucleus)
Organelles
Few present, none
membrane bound
Many organelles:
•Double membranes e.g.:
nucleus, mitochondria &
chloroplasts
•Single membrane e.g.:
GA, ER & lysosomes
Cell walls
Rigid formed from
glycoproteins (mainly
murein)
•Fungi: rigid, formed from
polysaccharide, chitin.
•Plant: rigid, formed from
polysaccharides. E.g.:
cellulose.
•Animals no cell wall
Ribosome’
s
70s 80s
Differences