The document describes various parts of cells and how substances move across cell membranes. It discusses the structures and functions of mitochondria, lysosomes, peroxisomes, centrioles, microtubules and other organelles. It also explains the three main ways that substances traverse the cell membrane: passive diffusion, active transport, and endocytosis/exocytosis. Specific transport mechanisms like osmosis, carrier-mediated transport, and receptor-mediated endocytosis are also outlined.

1. CELL PARTS AND
FUNCTIONS

2. Cell Parts and Functions

3. Cell Parts and Functions
Mitochondria – the powerhouse of the
cell. It converts the potential energy
of food molecules into ATP.
Microfilaments – also called actin
filaments that are found just beneath
the cell membrane providing support
and maintaining cell shape.
Lysosome- the suicidal bag of the cell
for it contains hydrolytic enzymes that
can break down large macromolecules
and also engulfs another organelle
specially the damaged ones.

4. Cell Parts and Functions
Peroxisome- contains enzymes that
can help detoxify alcohol and other
harmful substances and convert
poisonous peroxides to water. It also
plays an important role in the
hydrolysis of fatty acids into simple
units that can be utilized by the
mitochondria for the process of
cellular respiration.
Centrioles – associated with the
formation and anchoring of the
spindle fibers during cell division of
animal cell

5. Cell Parts and Functions
Microtubules – plays an important role
in intracellular transport, formation of
mitotic spindle fiber needed for the
cell division, and formation of cell wall
in plant cells.
Smooth Endoplasmic Reticulum –
performs functions like lipid synthesis,
carbohydrate metabolism, and help in
the detoxification of drug and poison.

6. Cell Parts and Functions
Golgi apparatus – performs unique
functions of manufacturing,
processing, and packaging
macromolecules like protein and other
products and secretions before they
are sent to their respective
destinations.
Cilia – structures for locomotion of
cell
Ribosomes- these are where proteins
are manufactured. They are the
protein factories of the cell.

7. Cell Parts and Functions
Rough Endoplasmic Reticulum-
provides surface for ribosomes where
synthesis of many secretory proteins
takes place.
Chromatin- to package DNA into a
smaller volume to fit in the cell, to
strengthen the DNA to allow mitosis,
to prevent DNA damage, and to
control gene expression. It contains
the gene as well.

8. Cell Parts and Functions
Nucleus- contains the genetic material
that directs the production of protein
and other many cellular processes. It
is the central command of the cell
center of the cell. Its main function is
to control gene expression and initiate
DNA replication.
Nuclear Envelope- protects the
nucleus.

9. Cell Parts and Functions
Nucleolus- it is where components of
ribosomes and Rrna are synthesized.
These components pass through the
nuclear membrane into the cytoplasm
where they are combined to form
ribosomes.
Nuclear Pores – allows the passage of
small water-soluble molecules in and
out of the nucleus.

10. Cell Parts and Functions
Cytoplasm/ Plasma Membrane- the
region found outside the nucleus
surrounded by cell membrane. This
contains semifluid translucent
substance called cytosol. Important
cellular processes such as cell division
take place in the cytoplasm.
Suspended in the cytoplasm are
membrane-bound organelles each
performing specific functions all
directed for the survival of the cell
and the cell and the individual as a
whole.

11. Cell Parts and Functions
Cell Membrane – a dynamic membrane
separating the interior of the cell from
the outside environment. Aside from
enclosing the cell, it gives form and
shape to the cell. It is semi-
permeable.

12. Plant Cell

13. TRANSPORT ACROSS
MEMBRANES

14. 2 Major Kinds of Cell Transport
1. Passive Transport – it is the
movement of molecules without the
expenditure of energy.
2. Active Transport - it is the movement
of molecules where energy is exerted
by the cell.

15. 3 Ways of Traversing the Cell Membrane
A substance may traverse the cell
membrane in three principal ways:
1. By Diffusion and Osmosis
2. By Carrie-Mediated Transport
System
3. By Endocytosis
I.DIFFUSION
 The movement of particles from an
area of a higher concentration to an
area of lower concentration of the
particles or molecules, thus tending

16. 3 Ways of Traversing the Cell Membrane
to equalize the concentration
throughout the area of diffusion.
Simple Diffusion – the particle is
transported through the membrane
without the aid of permease and
without expenditure of energy by the
cell.

17. 3 Ways of Traversing the Cell Membrane
II. OSMOSIS
It is the movement of water molecules
or solvents through a semi-permeable
membrane from a lower osmotic
pressure to greater osmotic pressure
Osmotic Pressure – the physical
pressure that exactly balances the
osmosis of water due to the
concentration difference between a
solution and pure water.

18. 3 Ways of Traversing the Cell Membrane
“ OSMOSIS IN ANIMAL AND PLANT CELL
AND THE TYPES OF SOLUTION”
Turgor Pressure – the pressure that
tends to force water molecules out of
the cell.
Diffusion Pressure – the force or
pressure that causes water molecules
to diffuse into the cell.

19. 3 Ways of Traversing the Cell Membrane
THREE TYPES OF SOLUTION DURING
OSMOSIS
1. Isotonic Solution – a solution whose
osmotic pressure is equal top at of the
cell, no change will occur thus a
balance is maintained (equilibrium).
2. Hypertonic Solution- a solution
whose osmotic pressure is greater
than that of the cell.
- It will cause water to leave the cell,
thus the cell will shrink or crenate.

20. 3 Ways of Traversing the Cell Membrane
3. Hypotonic Solution – a solution
whose osmotic pressure is lower than
that of the cell
- It will cause water to enter the cell,
thus the cell will swell or hemolyze or
even burst in animal cell.

21. 3 Ways of Traversing the Cell Membrane
“ Diffusion Through Channels”
The diffusion of ions could be allowed
at all times or they may need signals
to open or close
* Chemically- Gated Ion Channels
- When a signalling molecule binds to
specific binding site on the
transmembrane protein
* Voltage- Gated Ion Channels
- When the ionic charge across a plasma
membrane changes

22. 3 Ways of Traversing the Cell Membrane
III. CARRIER-MEDIATED TRANSPORT
Carriers or Transporters- these are
special transmembrane proteins that
enable solute molecules to cross the
phospholipid bilayer
- They are usually quite specific,
recognizing and transporting only a
limited group of chemical substances or
perhaps even a single substance.

23. 3 Ways of Traversing the Cell Membrane
“FACILITATED DIFFUSION”
A transporter assists a molecule to
diffuse through the membrane that it
cannot otherwise penetrate
- Sponsors movement only in a
“downhill” movement, along a
concentration gradient where no
metabolic energy is required
- Example is the transport of GLUCOSE
(blood sugar) in cells

24. 3 Ways of Traversing the Cell Membrane
III. ENDOCYTOSIS
The ingestion of material by cells,
they are pathways for specifically
internalizing solid particles, small
molecules and ions, and
macromolecules, requires energy.
Examples are the following:
1. Phagocytosis- “cell eating”
- A common method among protozoa,
lower metazoan and white blood cells

25. 3 Ways of Traversing the Cell Membrane
- Digestion via lysosomal enzymes once
a phagosome detaches
2. Pinocytosis- small areas of the
surface membrane are invaginated in
cells to form tiny vesicles (aveolae)
- For the intake of vitamins,and similar
mechanisms may be important in
translocating substances from one
side of the cell to the other and
internalizing signal molecules
- Examples are hormones

26. 3 Ways of Traversing the Cell Membrane
3. Receptor-Mediated Endocytosis
Bring large molecules within the cell
A ligand (particular molecule) binds to
the plasma membrane.
Invaginations covered with the
protein clathrin are created (clathrin-
coated pits)
Invaginations uncoats, the receptor
and the ligand separates
Lysosome attacks the remaining
vesicle, the endosome

27. 3 Ways of Traversing the Cell Membrane
Contents are digested and absorbed in
the cytoplasm
EXOCYTOSIS
Extruding contents to the surrounding
medium
Removal of undigestible residues of
substances brought in by endocytosis,
to secrete substances such as
hormones and to transport a
substance completely across a cellular

28. 3 Ways of Traversing the Cell Membrane
barrier ( TRANSCYTOSIS)
Actin and actin- binding proteins are
essential cytoskeletal components in
the process of endocytosis and
exocytosis.