1. Introduction to Molecular Cell Biology Unit of Life
Dr. Fridoon Jawad Ahmad
HEC Foreign Professor
King Edward Medical University
Visiting Professor LUMS-SSE

2. Overview

3. Life is not a random collection of some macromoleulces.
Life is not a random collection of some macromoleulces.
Life is a collection of macromoleulces that can perform unique functions because the are enclosed in structural acompartment that provides consistency (homeostasis).
All organisms are composed of cells the basic unit of life and all cells come from preexisting cells

4. Cells are small to maintain large surface area to volume ratio.
Cells are small to maintain large surface area to volume ratio.
Larger volume requires a grater exchange of materials from out side which is a function of surface area.

5. Prokaryotic Cells No membrane enclosed internal compartments.
No membrane enclosed internal compartments.
The plasma membrane regulates traffic is a barrier.
Nucleoid region contains DNA, most have cell wall.
Support & Cell shape
Protection From Phagocytes

6. Special Prokaryotic Cells
Cyanobacteria Chlorophyll containing have folds of plasma membrane, other have mesosomes (energy).
Some have actin like filaments and other have Flagella made-up of Flagellin.

7. Eukaryotic Animal Cell

8. Plasma Membrane
The PM is composed of a phospholipid bilayer, with the hydrophilic “heads” of the lipids facing the cell’s aqueous interior on one side of the membrane and the extracellular environment on the other

9. Plasma Membrane constant internal environment
constant internal environment
selectively permeable barrier
communicating with adjacent cells and receiving extracellular signals
binding and adhering to
adjacent cells

10. The Nucleus The nucleus is the site of DNA duplication.
The nucleus is the site of DNA duplication.
The nucleus is the site of genetic control of the cell’s activities.
A region within the nucleus, the nucleolus, begins the assembly of ribosomes from specific proteins and RNA.

11. The Nucleus
2 membranes

12. Chromatin and Chromosome

14. Ribosomes Free or attached to ER involved in protein synthesis.
Free or attached to ER involved in protein synthesis.
Present in Mitochondria & Chloroplasts.
Contain protein and RNA.

15. RER Segregates newly synthesized Proteins.
Segregates newly synthesized Proteins.
Chemically modifies proteins (Glycosylation adress)

16. Secreting and detoxifying cells have abundant SER
Glycogen hydrolysis.
Secreting and detoxifying cells have abundant SER
Cis, Medial & Tarns

17. Manufactures poly-saccharides for the plant wall.
Golgi Apparatus
The Golgi apparatus receives materials from the rough ER and modifies them.
Concentrates sorts and packages proteins and sends them to other destinations.
Manufactures poly-saccharides for the plant wall.

18. Lysosomes contain many digestive enzymes.
Lysosomes contain many digestive enzymes.
Lysosomes fuse with the phagosomes produced by phagocytosis (autophagy) to form secondary lysosomes, where engulfed materials are digested.
Undigested materials are secreted from the cell when the secondary lysosome fuses with the plasma membrane..

19. Breakdown fuel molecules to make ATP.
Mitochondria
Breakdown fuel molecules to make ATP.
Some protists have one, liver more than a thousan and egg a few hundred thousand MT.
Mitochondria and chloroplasts contain their own DNA and ribosomes for making some of their own proteins.

20. Endosymbiosis
The endosymbiosis theory of the evolutionary origin of mitochondria and chloroplasts states that these organelles originated when larger prokaryotes engulfed, but did not digest, smaller prokaryotes.
Mutual benefits permitted this symbiotic relationship to be maintained, allowing the smaller cells to evolve into the eukaryotic organelles observed today.
Photosynthesis
Detoxification of O2

21. Cytoskeleton
Microfilaments: Cell shape (change), cellular motion, contraction, cytoplasmic streaming & cytokinesis
Intermediate filaments: Rope like stabilize cell shape, resist tensile forces, cell adhesion & nuclear lamina.
Microtubules: Long hollow dynamic, move chromosomes & transport.

22. Cytoskeleton Actin (cortical) Stabilizes cell shape.
Generates movement local general.
Constriction ring in cell divission (Cytokinesis). Movement of cytoplasam (cytoplasmic strreaming).
IF stabilize cell structure (hold organelles).
Stabilize and maintain tissue rigidity (desmosomes).
Lamins in nucleus.
Resist tention.

23. IF in Desmosomes

24. movements
The movements of cilia and flagella result from the binding of the motor protein dynein to the microtubules.
Dynein and another motor protein, kinesin, also bind to microtubules to move organelles through the cell.

25. Celia are Made of Microtubules

26. ECM in Animals
Bone