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1. M.Prasad Naidu
MSc Medical Biochemistry, Ph.D,.

2. Importance:
Division of labor
Increased Surface Area
Regulation

3. Prokaryotes
Simplest
No organelles
No nucleus
No membrane bound organelles
DNA uncomplexed by histones

4. Prokaryotes

5. Prokaryotes
Prokaryotes can live in the coldest, hottest, most
acidic and most highly pressurized environments.
They can live in places such as beneath the earth in
bare rock, under glaciers, floating around in clouds
and miles down on the sea floor at temperatures
greater than 100 C.

6. Bacteria

7. Bacteria
Bacteria live mostly on the surfaces of objects where
they grow as colonies.
 Bacteria are important in making soil, feeding cows,
controlling insects, making medicines, making
bioplastics, making plants grow, degrading pollutants
such as oil and plastics as well as in causing disease.

8. Bacteria
Most bacterial species are un-named and unidentified
Tens of thousands of species have been isolated
There are more than 15,000 known species of bacteria
living in the sea
Most famous is E.coli (Escherichia coli)

9. E. coli

10. E.coli
well studied
cell envelope
plasma membrane constitutes #2
pili (for adherence to cells)
flagella (for propulsion through aqueous
environment)
chemistry similar to ours

11. E.coli
Some strains frequently cause diarrhea in
travelers, and it is the most common cause of
urinary tract infections
One strain, designated O157:H7, is particularly
virulent and has been responsible for several
dangerous outbreaks in people eating
contaminated food (usually undercooked
hamburger).
Several important drugs (insulin, for example) are
now manufactured in E. coli

12. Eukaryotes
More complex
More DNA
Has to be folded
histones (positively charged proteins)

14. Plasma membrane
compartmentalization
huge number of proteins
transporters (nutrient carriers)
receptors (signal transduction)
 lipids and protein
semi-permeable (polar and charged ions
cannot cross freely)

15. Nucleus
double membrane
contains DNA
genetic material
chromatin vs. chromosomes
nucleolus has RNA
histones: proteins that are positively charged that wind
up DNA

16. Endoplasmic Reticulum
Rough ER:
ribosomes
protein synthesis occurs here for those proteins that
will be routed out of cell
Smooth ER
lipid synthesis
metabolism of drugs and toxic substances

17. Golgi
Cellular post office
Proteins synthesized in the ER are packaged with
extras such as
SO4
2-
, carbohydrates, lipid moieties
Then, the proteins are directed to either the cell
membrane to outside the cell or within the cell.
In other words, the proteins are flagged for their next
destination

18. Mitochondria
ATP production
has its own DNA
uses nutrients to make energy
In plants, chloroplasts makes sugar from sunlight
Endosymbiotic theory

19. Lysosomes (Animal Cells)
Recycling centers can breakdown proteins
in plant cells these are vacuoles

20. Peroxisomes
Breakdown H2O2

21. Cytoskeleton
internal organization, assists the plasma membrane
in retaining cell shape, and allows the cell to move
microtubules
rods from tubulin
arrangement
motion
Actin: protein filament for cell rigidity
Myosin: moves along actin using ATP

22. http://www.ucmp.berkeley.edu/alllife/virus.html

23. Viruses
Contains nucleic acid surrounded by protective
shell or capsid
Uses host cells enzymes and ribosomes for
replication
Lysogenic phase: viruses may remain dormant
inside host cells for long periods. There is no
obvious change in their host cells
Can enter the lytic phase: new viruses are
produced, assemble, and burst out of the host cell.
The cell is killed and other cells are infected

24. Famous Viruses
Smallpox, common cold,
chickenpox, influenza, shingles,
herpes, polio, rabies
Ebola
AIDS

25. Bacteriophages
Viruses that infect bacteria
Commonly used in molecular biology
DNA isolated from tissue---> Packaged into
bacteriophage DNA---> Bacteria culture grown
and infected with bacteriophage---> DNA of
interest is replicated and studied either on DNA
level or protein level