1. Molecular Biology Department of Medical Laboratory Technology
(MLMB-201)
Department of Medical Laboratory Technology
Faculty of Allied Medical Science
Lecturer:
Dr. Mohamed Salah El-Din

2. Intended Learning Outcomes (ILO’s):
Molecular biology course provides an overview of the molecular basis to cell structure and function.
This course focuses on the structure, biosynthesis and function of DNA and RNA on the molecular level and how these interact among themselves and with proteins. Molecular biology techniques are essential for modern biological and medical research. This course will give you an introduction to DNA and RNA standard techniques.
Student will have basic knowledge of:
Cell organization.
DNA structure and function.
DNA Extraction.
RNA structure and function.
RNA Extraction.
Gene expression and protein biosynthesis.
Agarose gel electrophoresis for DNA/RNA; and SDS-PAGE for protein.
Polymerase Chain Reaction (PCR) – Theory, Types, Application.
Gene library and screening
DNA sequencing

3. A Cell organization A1 Prokaryotes A2 Eukaryotes
A3 Cellular fractionation

4. Cells
Fundamental working units of every living system.
Every organism is composed of one of two
radically different types of cells:
prokaryotic cells or
eukaryotic cells.
Prokaryotes and Eukaryotes are descended from the same primitive cell.
All extant prokaryotic and eukaryotic cells are the result of a total of 3.5 billion years of evolution.

5. Cells 70% water 7% small molecules 23% macromolecules salts Lipids
Chemical composition-by weight
70% water
7% small molecules
salts
Lipids
amino acids
nucleotides
23% macromolecules
Proteins
Polysaccharides
lipids
biochemical (metabolic) pathways
translation of mRNA into proteins

6. Life begins with Cell
A cell is a smallest structural unit of an organism that is capable of independent functioning
All cells have some common features

7. All Cells have common Cycles
Born, eat, replicate, and die

8. Prokaryotes and Eukaryotes
According to the most recent evidence, there are three main branches to the tree of life.
Prokaryotes include Archaea (“ancient ones”) and bacteria.
Eukaryotes are kingdom Eukarya and includes plants, animals, fungi and certain algae.

9. Prokaryotes and Eukaryotes, continued
Single cell
Single or multi cell
No nucleus
Nucleus
No organelles
Organelles
One piece of circular DNA
Chromosomes
No mRNA post transcriptional modification
Exons/Introns splicing

10. A1 Prokaryotes
Prokaryotes
Cell structure
Bacterial cell walls

11. Prokaryotes
Prokaryotes are the most abundant organisms on earth. (bacteria and blue-green algae)
A prokaryotic cell dose not contain a membrane-bound nucleus.
Size from 0.1 to 10 μm

12. Three basic shapes Spherical(cocci) Rodlike(bacilli)
Helically coiled( spirilla)
They fall into two groups:the eubacteria and the archaebacteria.

13. The eubacteria Gram-positive Gram-negative
Cyanobacteria (cyano-bacteria)
in soil,water and living in or on larger organisms

14. The archaebacteria Sulfur bacteria Methanogens（methane）
They grow in unusual environments:
salt brines,hot acid springs,in the ocean depths

15. Cell structure
Each prokaryotic cell is surrounded by a plasma membrane.
The cell has no subcellular organelles,only infoldings of the plasma membrane called mesosomes.
The deoxyribonucleic aid (DNA) is condensed within the cytosol to form the nucleoid.
Some prokaryotes have tall-like flagella.

16. Cell structure

17. Bacterial cell walls
The peptidoglycan (protein and oligosacca-ride) cell wall protects the prokaryotic cell from mechanical and osmotic pressure.
A Gram-positive bacterium has a thick cell wall surrounding the plasma membrane,whereas Gram-negative bacteria have a thinner cell wall and outer membrane,between which is the periplasmic space.

18. Gram negative cell walls

19. A2 Eukaryotes Chloroplasts Lysosomes Eukaryotes Plasma membrane
Peroxisomes
Cytosol
Cytoskeleton
Plant cell wall
Plant cell vacuole
Eukaryotes
Plasma membrane
Nucleus
Endoplasmic reticulum
Golgi apparatus
Mitochondria

20. Plant cell

21. Animal cell

22. Plasma membrane

23. Cell nucleus

24. Golgi

25. Mitochondria structure

26. Chloroplast

27. Plant cell wall

28. vacuole

29. The cell structure 1

30. A3 Cellular farctionation
Subcellular fractionation
Differential velocity centrifugation
Equilibrium density-gradient centrifugation
Rate-zonal centrifugation
Marker enzymes
Flow cytometry

31. Differential velocity centrifugation

33. Some Terminology Genome: an organism’s genetic material
Gene: a discrete units of hereditary information located on the chromosomes and consisting of DNA.
Genotype: The genetic makeup of an organism
Phenotype: the physical expressed traits of an organism
Nucleic acid: Biological molecules(RNA and DNA) that allow organisms to reproduce;

34. The genome is an organism’s complete set of DNA.
More Terminology
The genome is an organism’s complete set of DNA.
a bacteria contains about 600,000 DNA base pairs
human and mouse genomes have some 3 billion.
human genome has 24 distinct chromosomes.
Each chromosome contains many genes.
Gene
basic physical and functional units of heredity.
specific sequences of DNA bases that encode instructions on how to make proteins.
Proteins
Make up the cellular structure
large, complex molecules made up of smaller subunits called amino acids.

35. All Life depends on 3 critical molecules
DNAs
Hold information on how cell works
RNAs
Act to transfer short pieces of information to different parts of cell
Provide templates to synthesize into protein
Proteins
Form enzymes that send signals to other cells and regulate gene activity
Form body’s major components (e.g. hair, skin, etc.)

36. Assignment:
As a part of the semester activity, one student is selected every week to prepare a short seminar about his/her point of interest in one of the lecture topics. That to be discussed and evaluated during the next lecture.