The plasma membrane, cytoplasm, and nucleus are the three major parts of the cell. The plasma membrane is a double layer that selectively permits movement of molecules in and out of the cell and protects the cell. The cytoplasm contains organelles and structures that carry out the cell's functions. The nucleus is the control center and contains the cell's genetic material.

2. Three Major Parts of
the Cell:
1. Plasma Membrane
2. Cytoplasm
3. Nucleus

5. • Siomai-like
• Structure: Double layer of phospholipid molecules
• Proteins are embedded in it.
• Two Kinds of Protein: Integral and Peripheral Proteins
• Phosphate Head: Polar and Hydrophilic
• Lipid Tail: Nonpolar and Hydrophobic

6.  Structure: Fluid mosaic model
 “Fluid” – configuration of the phospholipid
molecules
 “Mosaic” – presence of proteins
 Lipid and other molecules move about in the
membrane.
 The plasma membrane is not smooth.

7.  Functions:
1. Selectively permeable
2. Protects the cell
3. Separates the cell from its environment
4. Gives shape to the cell
 “Plasma” – living
 Paramecium – pellicle

8.  First structural part to be observed
 Structure: Spherical in shape and located at the center of the cell
 It has three parts:
1. Nucleoplasm
2. Nucleolus
3. Nuclear Envelope /
Nuclear Membrane

9. 1. Nucleoplasm
- protein-rich protoplasm where nucleolus and chromatins
are suspended
- Chromatins become chromosomes when the cell is dividing.
2. Nucleolus
- Darker area, for synthesis and storage of RNA
3. Nuclear Membrane / Nuclear Envelope
- Double membrane separating the nucleus from cytoplasm
- Prokaryotic Cell and Eukaryotic Cell
- Not a solid barrier (has nuclear pores)

10.  Prokaryotes
- cells with no distinct nucleus
Ex.
Bacteria
 Eukaryotes
- cells with distinct nucleus
Ex.
Animal Cell

12. • Control Center of the Cell
• Contains most of the cell’s genetic material
(DNA)

13.  Two Types:
1. Cytoplasm – protoplasm lying around the nucleus
2. Karyoplasm / Nucleoplasm – protoplasm lying inside the
nucleus
* The structure enclosed within the cell membrane and
outside the nucleus is the cytoplasm.

15. • Material between the cell membrane and the nucleus
• Appears:
1. Clear
2. Viscous
3. Colloidal
Found in are different structures:
1. Endomembrane System
2. Organelles
3. Supramolecular Complex

16. Endoplasmic Reticulum (ER)
 Structure: Network of membranes; tiny canals
formed by two parallel membranes
 Two distinct regions:
1. Rough ER
2. Smooth ER

17. 1. Rough ER
 Appears rough because of the presence of ribosomes
 Many types of specialized cells secrete proteins
produced by the RER (Ex: White Blood Cell in a
human).
 Proteins destined for secretion are synthesized by
ribosomes attached to RER (Ex: Glycoproteins).

18. 2. Smooth ER
 Its enzymes synthesize fats, phospholipids,
steroids, and other lipids.
 Carbohydrate Metabolism – done by SER in
the liver
 Its enzymes detoxify drugs and other
poisons.

19. Serves as a channel for products produced in the cell

20. Golgi Apparatus
• Discovered by Camilo Golgi (nerve cell of an owl)
• Flattened membranous sac

21. Functions:
• Works together with the ER.
• Serves as the Package Counter of the Cell
After processing and packaging of substances in the golgi
apparatus, a clean up is needed. Cleaning is done by the
lysosome.

22. - Various structures like miniature organs that perform
specific functions

23. 1. Lysosomes
 Not commonly found in plant cells
 Membrane-bound organelles
 Contain hydrolytic enzymes
 These enzymes hydrolyze the cell when the lysosomial
membrane is damaged.
 What does hydrolytic enzyme do?
1. Breakdown of macromolecules (proteins, lipids,
carbohydrates)
2. Destroys bacteria and other microorganisms
3. Destroys old cells (Programmed cell destruction)
 “Suicide Bag of Cell”

24. Organelles
2. Mitochondrion
 May be single or few in some cells, but
most often a cell has hundreds or
thousands of mitochondria.
 Structure:
 Rod-shaped organelles
 Size ranges from being small to bigger
sauge-like structure.
 Has 2 membranes:
1. Outer membrane – smooth and separates
mitochondria from the cytoplasm
2. Inner membrane – with an enfolding
called Cristae (where important reactions
in the mitochondria take place)

25. Mitochondria
 Generates energy (Power House of the Cell)

26. 3. Cytoskeleton
 Network of fibers
floating through the
cytoplasm
 Functions:
a. Gives mechanical
support to the cell
b. Transport for some
proteins and
organelles
c. Associated with
motility

27. 3. Cytoskeleton
 Has 3 components:
a. Microtubules – for movement (Ex:
Cilia and Flagella)
- contain Tubulin
b. Microfilament – for muscle
contraction
- contains Actin
c. Intermediate Filaments –
reinforce the shape of the cell

28. 4. Vacuoles
 Mostly found in plant cells
 Fluid-filled sacs surrounded by a membrane
 Mature plant cells have a single large vacuole.
 Plant Stem – cell sap

29. 5. Plastids
 Found in most plant cells
 Contain color pigments
 Two Kinds:
 Chromoplast – colored plastids
Ex: Chloroplast – contains chlorophyll
 Leucoplast – colorless plastids; for storage of food
substances

30. Ribosomes
 Tiny dot-like structures
scattered throughout the
cytoplasm
 Site where proteins are
assembled
 “Protein Factories of the Cell”

32. Functions:
1. Protects the cell from mechanical injury
2. Gives rigidity to plant cell
 Cell wall is porous.
 Composed mainly of cellulose
 Also contains lignin