1. There are 4 Concepts of Cell Theory (Definition)
The Living Units
There are 4 Concepts of Cell Theory (Definition)
Basic Structure and functional units of life
All activities for life occur in cells
Human body contains 3 trillions of cells
Biochemical activities of a cell are dictated by their organelles

2. Video

3. Structure of the Basic Cell

4. Characteristics of a Cell
Plasma membrane
Is a double layer of phospholipids, cholesterol and proteins and encloses the cell as outer layer : Selective permeability
Cytoplasm: is a clear substance that consists of all of the contents outside of the nucleus of a cell
The cytosol or intracellular fluid (ICF) or cytoplasmic matrix is the liquid found inside cells.
Organelles or a cell organs. Specialized part of a cell having some specific function;
Different in Size shape and function
All Cells are composed primarily of Carbon, Hydrogen and Nitrogen and Oxygen
All Cells have the same basic parts and some common functions
Typical cell has: plasma membrane , cytoplasm , cytosol, organelles and nucleus
Nucleus: contains the majority of the cell's genetic material in the form of multiple linear DNA molecules organized into structures called chromosomes.

5. The Structure of The Cell

6. CELLS VARY GREATLY IN SIZE , SHAPE AND FUNCTIONS
ALL CELLS ARE COMPOSED OF PRIMARILY CARBON , HYDROGEN, NITROGEN AND OXYGEN
All cells have same basic parts and some common functions
A generalized human cell contains the plasma membrane , the cytoplasm, and the nucleus

7. The Structure of The Cell
The Plasma Membrane :
The Cytoplasm
Nucleus
Organnes

8. The Structure of The Cell
The Plasma Membrane:
Is made up of double layer of phospholipids, cholesterol and proteins
Inwards facing and outward facing – have different amount of lipids they contain
Glycolipids, lipid rafts in outer layer cell signal
Plasma membrane is selectively permeable barriers
Passive process
Diffusion
Osmosis
filtration
Active process
Use energy to transport (ATP)
Use solute pumps

9. The Cytoplasm
The cellular membrane between the cell membrane and the nucleus .
Most cell activities occur here
The major elements of the cytoplasm
Cystosol: located in the cytoplasm inside the plasma membrane and contains water fluid
Cytoplasmic Organelles: small organs found in the Cystosol:
E.g. Nucleus , Mitochondria, ribosomes, Endoplasmic Reticulum,
Golgi Apparatus , lysosomes, and cytoskeleton

10. Nucleus
Almost all Cells have Nucleus : These are spherical bodies found inside the cytoplasm
Most cells have only one nucleus, but some like the skeletal muscles have more than one
Cells without nucleus : matured erythrocytes RBCs
A Nucleus is the largest organelle in the cell the controlling center of the cell
Nucleus contains the body’s genetic material which directs all metabolic activities of the body (46 Chromosomes) made up of Deoxyribonucleic acid DNA a fine network of thread called chromatins

11. Mitochondria ( Power house )
Shaped like sausage they are found in the cytoplasm
They are responsible for the energy of the cell:
They are responsible for aerobic respiration which produces chemical energy i.e. ATP

12. The Structure of The Cell
Endoplastic Reticulum ER
Golgi Apparatus
ER: series of canals in the cytoplasm- 2 types
Smooth
Rough
Smooth -ER synthesizes Fatty acids & Steroids and detoxify some drugs
Rough ER –synthesizes enzymes and hormones outside the cell
Are flat membranous sacs
Package proteins from ER to form secretory granules
Packages Digestive Enzymes into lysosomes

13. The Structure of The Cell
Lysosomes
Cytoskeleton
Spherical organelles contain Digestive Enzymes and other enzymes for breaking down RNA & DNA to be recycled to excluded as waste
Some lysosomes are in White Blood Cells WBCs where they breakdown foreign materials (Microbes)
These are tiny strands of protein include:
Microfilaments small fibers fro structural support
Microtubules helps in cell divisions and cell extensions & chromosomes to divide

14. The Structure of The Cell
Centrosome
Made up of small centrioles
For organization of microtubules within the cell
For cell division
Cell Extensions
These are projections from plasma membranes help in cell movement, Example:
CILIA: small hair like projections ( found in respiratory track)
FLAGELLA: long whip like projections

15. CELL CYCLE Cell cycle is the process that makes the life of each cell.
The life of a cell therefore is a series of changes a cell goes through from the time it is formed to the time it reproduces:
There are two Processes :
Interphase
Cell Division

16. CELL GRPWTH & REPRODUCTION
INTERPHASE
Is the first three steps where the cell:
Grows
Matures
Carries out its life function
The stage just before cell division

17. INTERPHASE INTERPHASE
Interphase occurs when the cell is not undergoing mitosis.
It engages in metabolic activity.
DNA duplicates
during this phase the cell prepares for mitosis.
Chromosomes are not visible in the nucleus
yet and only chromatin is present.
Cells spend the majority of their cycle in interphase.

18. CELL GROWTH

19. CELL DIVISION Most body complete body Cell division by mitosis
Mitosis involves a process that results in two new genetically identical cells.
Other cell division are:
MEIOSIS
CYTOKINESIS
Meiosis: Involves formation of gametes ( sex cells) ova and spermatozoa