It tackles about the different organelles of a cell and their functions.

3. BASIC BODY STRUCTURE AND
ORGANIZATION

4. PARTS OF THE CELL
THE CELL CAN BE SUBDIVIDED INTO THREE PARTS:
1. PLASMA (CELL) MEMBRANE
2. CYTOPLASM
 CYTOSOL
 ORGANELLES
3. NUCLEUS
CHROMOSOMES
GENES

5. PARTS OF THE CELLS (PRIMARY
COMPONENTS)

6. PRIMARY COMPONENTS
Cell membrane — a phospholipid
bilayer which also contains cholesterol
and proteins; its functions are to provide
support and to control entrance and exit
of all materials.
We will discuss the structure of the cell
membrane and the mechanisms by
which chemicals can penetrate or be
absorbed into or out of the cell

7. PRIMARY COMPONENTS
•Cytoplasm — a watery
solution of minerals,
organic molecules, and
gases found between
the cell
membrane and nucleus.

8. CYTOSOL
• The aqueous component
of the cytoplasm of a
cell, within which various
organelles and particles
are suspended.

9. ORGANELLES
• Organelles are tiny
structures that perform
very specific functions
within cells. The term is a
reference to organs,
likening the way these
structures operate in cells
to the way organs function
in the body.

10. PRIMARY COMPONENTS
CYTOSKELETON - A system of
filaments or fibers that is present in
the cytoplasm of eukaryotic cells . The
cytoskeleton organizes
other constituents of the cell, maintains
the cell’s shape, and is responsible for
the locomotion of the cell itself and the
movement of the
various organelles within it.

11. THREE TYPES OF CYTOSKELETON
1. MICROTUBULES
• Microtubules appear like small, hollow, round tubes with a diameter of about
24 nanometers. They are made up of a protein, tubulin.
• Thirteen tubulins link to form a single tube.
• Microtubules are very dynamic structures, which reveal that they can change
quickly.
• They keep growing or shrinking steadily. These help in transporting cellular
materials and dividing chromosomes during cell division.

12. 2. MICROFILAMENTS
• Microfilaments are thread-like protein
fibres, 3-6 nm in diameter.
• They are particularly found in muscle
cells.
• They consist of the protein actin,
responsible for muscle contraction.
• These are also responsible for cellular
movements including cytokinesis,
contraction, and gliding.

13. 3. INTERMEDIATE
FILAMENTS
• The intermediate filaments are
about 10 nm in diameter and
provide tensile strength to the
cell.
• They facilitate the formation of
keratins and neurofilaments.

14. CYTOSKELETON FUNCTIONS
The important cytoskeleton functions are mentioned below:
1. It provides shape and support to the cell.
2. It helps in the formation of vacuoles.
3. It holds different cell organelles in place.
4. It assists in cell signalling.
5. It supports intracellular movements like the migration of cell
organelles, transportation of vesicles in and out of the cell, etc.

15. PRIMARY COMPONENTS
Centrioles — there are
two centrioles,
aligned at right angles,
each composed
of 9 microtubule triplets;
they organize
specific fibers of
chromosomes during
cell division, which
move the chromosomes.

16. PRIMARY COMPONENTS
Cilia and flagella are cell organelles that are structurally similar
but are differentiated based on their function and/or length. Cilia
are short and there are usually many (hundreds) cilia per cell.
On the other hand, flagella are longer and there are fewer
flagella per cell (usually one to eight).
Flagella are used to move an entire cell. Cilia are used to
move entire cells or substances along the outer surface of
the cell.

17. PRIMARY COMPONENTS
Ribosomes use
information provided
by the nuclear DNA to
manufacture proteins.
Cells differ in the type
of protein they
manufacture.

18. • The endoplasmic reticulum (ER) is a system of
channels that is continuous with the nuclear
membrane (or “envelope”) covering the nucleus and
composed of the same lipid bilayer material.
• The ER can be thought of as a series of winding
thoroughfares similar to the waterway canals in
venice.
• The ER provides passages throughout much of the
cell that function in transporting, synthesizing, and
storing materials.

19. •Endoplasmic reticulum can exist in
two forms: rough ER and smooth ER.
•Rough ER (rer) is so called because
its membrane is dotted with
embedded granules—organelles
called ribosomes, giving the rer a
bumpy appearance.

20. PRIMARY COMPONENTS
Golgi apparatus —
stacks of flattened
membranes containing
chambers; they
synthesize, store, alter,
and package secretory
products.

21. PRIMARY COMPONENTS
Lysosomes — vesicles that
contain strong
digestive enzymes; lysosomes
are responsible for the
intracellular removal of
damaged organelles or
pathogens.

22. PRIMARY COMPONENTS
Mitochondria —
oval organelles bound by
a double membrane with
inner folds enclosing
important
metabolic enzymes; they
produce nearly all (95%)
of the ATP and energy
required by the cell.

23. AGING AND CELLS
AS WE AGE:
• Our cells gradually deteriorate in their ability to function
normally and in their ability to respond to environmental
stresses.
• The numbers of our body cells decreases.
• We lose the integrity of the extracellular components of
our tissues.