This describes the parts and functions of a cell.

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