1. The Cell

2. Cell Theory
The cell is the basic structural and functional unit of life
The organism activity depends on individual and collective activity of cells
Biochemical activities of cells are dictated by sub-cellular structure
For the Continuity of life the cellular basis is required

3. Cell Structure

4. Plasma Membrane
Separates intracellular fluids from extracellular fluids
Plays a dynamic role in cellular activity
Double Layered (bi-layer) of lipids with imbedded, dispersed proteins
Bi-layer consists of phospholipids, cholesterol, and glyco-lipids
Glycolipids are lipids with bound carbohydrate
Phospholipids have hydrophobic and hydrophilic bipoles

6. The phospholipid bi-layer is a
selectively permeable lipid bilayer found in all cells.
It contains a wide variety of biological molecules, primarily proteins and lipids
Theses structures are involved in a vast array of cellular processes such as
cell adhesion
ion channel conductance
cell signaling.
The plasma membrane also serves as the attachment point for both the intracellular cytoskeleton and, if present, the cell wall.

9. Stephen Taylor http://sciencevideos.wordpress.com

10. Stephen Taylor http://sciencevideos.wordpress.com

11. Fluid Mosaic Model

12. Functions of Membrane Proteins

13. Functions of Membrane Proteins

14. Membrane Junctions Adherance junctions:
Tight junction – impermeable junction that encircles the cell
Desmosome – anchoring junction scattered along the sides of cells
Hemi-desmosomes: anchoring the basal cell aspect to the basement membrane
Gap junction – a nexus that allows chemical substances to pass between cells

15. Adhering junctions

16. Membrane Junctions

17. Tight junctions

18. Membrane Junctions

19. Intercellular Junctions
Hemi-desmosome
Intercellular Junctions

20. Gap Junctions

21. Gap Junctions

22. Nucleus: The Cell's Brain
The nucleus is the most prominent organelle and can occupy up to 10% of the space inside a cell.
It contains the equivalent of the cell's gray matter—its genetic material, or DNA.
In the form of genes, each with a host of helper molecules, DNA determines the cell's identity, masterminds its activities, and is the official cookbook for the body's proteins.
The nucleus is surrounded by two pliable membranes, together known as the nuclear envelope.
Normally, the nuclear envelope is pockmarked with octagonal pits about an inch across (at this scale) and hemmed in by raised sides.
These nuclear pores allow chemical messages to exit and enter the nucleus.

23. Cell Nucleus
The nucleus is surrounded by two pliable membranes, together known as the nuclear envelope.
Normally, the nuclear envelope is pockmarked with octagonal pits about an inch across (at this scale) and hemmed in by raised sides.
These nuclear pores allow chemical messages to exit and enter the nucleus.
If you exclude the nucleus, the rest of the cell's innards are known as the cytoplasm.

24. Golgi Apparatus Stacked and flattened membranous sacs
Functions in modification, concentration, and packaging of proteins
Transport vessels from the ER fuse with the cis face of the Golgi apparatus
Proteins then pass through the Golgi apparatus to the trans face
Secretory vesicles leave the trans face of the Golgi stack and move to designated parts of the cell

25. Role of the Golgi Apparatus

26. Endomembrane System System of organelles that function to:
Produce, store, and export biological molecules
Degrade potentially harmful substances

27. System includes:
Nuclear envelope, smooth and rough ER, lysosomes, vacuoles, transport vesicles, Golgi apparatus, and the plasma membrane

28. Lysosomes Spherical membranous bags containing digestive enzymes
Digest ingested bacteria, viruses, and toxins
Degrade nonfunctional organelles
Breakdown glycogen and release thyroid hormone
Breakdown un-useful tissue
Breakdown bone to release Ca2+

29. Endoplasmic Reticulum (ER)
Interconnected tubes and parallel membranes enclosing cisternae
Continuous with the nuclear membrane
Two varieties – rough ER and smooth ER

30. Endoplasmic Reticulum (ER)
Gough ER
External surface studded with ribosomes
Manufactures all secreted proteins
Responsible for the synthesis of integral membrane proteins and phospholipids for cell membranes

31. Smooth ER Tubules arranged in a looping network
Catalyzes the following reactions in various organs of the body
In the liver – lipid and cholesterol metabolism, breakdown of glycogen and, along with the kidneys, detoxification of drugs
In the testes – synthesis of steroid- based hormones
In the intestinal cells – absorption, synthesis, and transport of fats
In skeletal and cardiac muscle – storage and release of calcium

32. Stephen Taylor http://sciencevideos.wordpress.com