This document summarizes the structures and functions of various cell organelles. It describes the plasma membrane as the outer boundary of the cell that regulates what enters and exits. It notes that the cytoplasm contains organelles and vesicles. Key organelles discussed include the nucleus that controls the cell, endoplasmic reticulum for protein and lipid storage, Golgi apparatus for sorting and secreting proteins, mitochondria as the powerhouse, lysosomes for digestion, and chloroplasts for photosynthesis in plant cells.

1. Cell Structures
and Functions
Presented by: Joevani S. Peñol

2. 1. Plasma Membrane
Outermost component of the
cell.
Encloses the cytoplasm and
forms the boundary between
material inside and materials
outside the cell.

3. Structure of the Plasma
Membrane
 The plasma membrane is a double layer
(bilayer) of proteins and phospholipids
and is fluid rather than solid.
 This can be interpreted by the fluid
mosaic model developed by Jonathan
Singer and Garth Nicolson in 1972.

5. Function of the Plasma
Membrane
 Regulate material moving into and out
of the cell.
 Separate the internal and external
part of the cell.
 Provide a large surface area on which
specific chemical reactions can
occur.

6. Functions of the Plasma
Membrane
 Separate cells from one another.
 Site for the receptors containing
specific cell identification markers
that differentiate one cell type from
the other.

7. 2. Cytoplasm
 Semifluid enclosed within plasma
membranes and are consist of
organelles, cytosol and other
structures.

8. Animal Cell

9. Function of the Cytoplasm
Dissolvessubstances and
houses organelles and vesicles.

10. 3. Nucleus
 Controlcenter of the cell.
 Contains nucleolus and DNA.

11. 4. Endoplasmic Reticulum
 an extensive membranous
network continuous with the
outer nuclear membrane.
 Contains series of channels and is
storage unit for enzymes and
other proteins.

12. Endoplasmic Reticulum

13. 2 Types of ER
Rough Endoplasmic Reticulum
Smooth Endoplasmic Reticulum

14. Rough Endoplasmic Reticulum
Attached to it is the ribosomes.

15. Microscopic view of Rough ER

16. Smooth Endoplasmic
Reticulum
 Sitefor lipid
production, detoxification of a
wide variety of organic
molecules and storage of
calcium ions in muscle cells.
 Don’t have ribosomes
attached on it.

17. Microscopic View of the
Smooth ER

18. 5. Golgi Apparatus
Collection of membranes
associated physically and
functionally with the ER in the
cytoplasm.
Named after Camillio Golgi,
1998.

19. Structure
 Composedof flattened stacks of
membrane bound cisternae

20. Function
 Sorts,packages, and secretes proteins
and lipids.

21. Golgi Apparatus/Golgi Bodies

22. 6. Mitochondrion
Double-membrane bound
organelles that are spherical to
elongate in shape.
Powerhouse of the cell.
Contains its own DNA.

24. 7. Lysosomes
Membrane bound spherical
organelles that contain
enzymes called acid
hydrolases, which are capable
of digesting organic molecules
under acidic conditions.

25. Microscopic view of the
Lysosome

27. 8. Centrioles
 Located within microtubule-organizing
center.
 Contains nine triplet microtubules
 Forms basal body of cilia and flagella.
 Function in mitotic spindle fiber
formation.

29. Microscopic view of the
Centriole

30. 9. Chloroplast
Found only in plant cells
Site of photosynthesis.
Contains its own DNA.

31. Chloroplast

32. 10. Ribosomes
Site of protein synthesis.

33. 11. Cilia/Flagella
Threadlike processes.
Move small particles past fixed
cells and are a major form of
locomotion in some cells.

34. Cilia and Flagella

35. 12. Vacuoles
Membrane surrounded, often
large sac in the cytoplasm.
Storage site of food and other
compounds, also pump water
out of a cell.

37. 13. Cytoskeleton
Interconnecting microfilament
and microtubules; flexible
cellular framework.
Assist in cell movement;
provides support; site for
binding of specific enzymes.

38. Cytoskeleton

39. 14. Peroxisomes
Small membrane bound
vesicles containing enzymes
that break down fatty acids,
amino acids, and hydrogen
peroxide (H2O2).

41. 15. Cell Wall
Rigid (up to many micrometers
in thickness) and gives plant
cells a very defined shape.
Composed of cellulose fiber,
polysaccharides, and proteins.

42. Function
1. Cell stability
2. Determines its shape,
3. Influences its development,
protects the cell against
pathogens
4. Counterbalances the osmotic
pressure.

43. Structure
Composed of primary and secondary cell
walls.

44. References
 http://www.phschool.com/science/biolo
gy_place/biocoach/cells/intro.html
 http://people.eku.edu/ritchisong/301note
s1.htm
 http://www.uic.edu/classes/bios/bios100/
summer2002/lect05.htm