1. Introduction to Microbiology
July 22, th Grade

2. Microbiology
the study of microscopic organisms, either unicellular, multicellular (cell colony), or acellular
Includes the disciplines virology, mycology, parasitology, bacteriology, and so on

3. Microbes Some are pathogenic Some are beneficial
Oldest form of life on earth
Simple life forms, reproduce rapidly
Found everywhere!!
Some are pathogenic
Some are beneficial

4. Major categories of microbes
Bacteria
Viruses
Parasites
fungi
And algae

5. Bacteria Morphology There are three basic shapes for bacteria
Cocci – round
Bacilli – rod shaped
Spirochetes – spiral

6. Bacteria Metabolic needs of bacteria 3 different types
Obligate aerobes
Need oxygen to survive
Aerobic respiration
Obligate anaerobes
Cannot survive in the presence of oxygen
Use fermentation
Facultative anaerobes
Can use both aerobic respiration and fermentation

7. Bacteria Cell Structure
Nucleoid
Where the DNA is generally found
DNA is in the form of a plasmid
Is not bound by a membrane, but is a visually distinct region in the cell
Cytoplasm
Everything enclosed by the plasma membrane
About 80% is water
Contains nucleic acids, enzymes, amino acids, carbohydrates, lipids, inorganic ions
Liquid component is called the cytosol

8. Quick Question What are the three shapes of bacteria?
Cocci, bacilli, spirochetes

9. Quick Question What method to obligate aerobes use?
Aerobic respiration
What about anaerobes?
Fermentation
Facultative anearobes?
Both

10. Bacteria Cell structure
Ribosomes
Look like little granules in the cytoplasm
Smaller than the ribosomes in Eukaryotic cells
But have a similar function: translating messenger RNA into proteins
Plasma Membrane
Lipid bilayer much like the plasma membrane of other cells
Has proteins that move within the layer that transport ions, nutrients, and waste
Cell Wall
Composed of peptidoglycan
Maintains overall shape of bacterial cell
Mycoplasma
Bacteria that have no cell wall = no defined shape

11. Bacteria Cell Structure
Pili
Hollow, hair-like structures made of protein
Allow bacteria to attach to other cells
Sex Pilus
A special kind of pilus
Allows the transfer of material from one bacterial cell to another
Flagella
Long appendages that rotate by means of a “motor” located just under the plasma membrane
For motility
Bacteria may have one or many flagella in different positions on the cell
flagellum video

12. Gram Staining
The layer of peptidoglycan protects the bacterial cell and is often associated with pathogenic bacteria because it serves as a barrier against phagocytosis by white blood cells

13. Quick Question Why does gram staining work?
Because of the layer of peptidoglycan
This layer differs between various bacteria…so you can test by staining.
Thick (significant) layer = gram positive (purple)
Holds the stain
Thin (insignificant) layer = gram negative (pink)
Can’t hold the stain…retains counterstain

14. Virus
Is a submicroscopic particle that can infect the cells of a biological organism
Are not plants, animals, or bacteria…but are parasites of the living kingdoms
Not considered to be living organisms

15. Virus The ultimate parasite Rely on their host for survival
Have genetic material (DNA or RNA) but lack ribosomes needed to translate it into proteins
Cannot generate or store energy in the form of ATP
Have to derive their energy and all other metabolic functions from the host cell
They basically take control of the host cell and use it for its needs
They also rob the host cell for the basic building materials
Amino acids, nucleotides, lipids

16. Viral Genetic Material
All viruses have DNA or RNA, but not both
It can be single or double stranded
This genetic material is then transcribed into proteins using the host cell’s machinery

17. Virus Structure
Can be complex (bacteriophage), helical, round, enveloped, or polyhedral in shape

18. Virus Capsid Is the protein shell that encloses the virus
Has three functions:
Protects the virus from digestion by enzymes
Contains special sites on its surface that allow the cell to attach to a host cell
Provides proteins that enable the virus to penetrate the host cell membrane

19. Virus
Viral envelope
Many viruses have a glycoprotein envelope surrounding the capsid
Is composed of a phospholipid bilayer, complete with interspersed proteins

20. Major viruses and their diseases
varicella zoster virus (chickenpox)
Influenza virus (flu)
Dengue virus (dengue fever)
Rabies virus (Rabies)
West Nile Virus
Herpes Zoster (shingles)

21. Quick Question Viruses are living organisms FALSE
Viruses have RNA but no DNA
Viruses have capsids that protect them and help them attach to host cells
TRUE

22. Parasite
Is any organism that uses a host to live in for food, shelter, protection, reproduction
Major types
Protozoa
Single celled organisms
Helminths
Worms

23. Parasite Protozoa Single celled eukaryotes Are motile
Are heterotrophic
Belong to kingdom protista
Can be free- living or parasitic
Paramecium
Amoeba
Euglena

24. Parasite Medically important protozoa:
Plasmodium malariae
Malaria parasite
From mosquitos
Interestingly…traits for sickle cell anemia give resistance to Malaria
Heterozygotes for the sickle cell gene are resistant to the disease.
Cells sickle and are removed from circulation faster, so the virus has less chance to replicate inside the host.

25. Parasite Medically important protozoa Trypanasoma Cruzi
Trypanasomiasis: which is transmitted to animals and people by insects and is found only in the Americas

26. Parasite Helminths (worms)
A worm or worm-like animal, that can be parasitic
Include roundworm, tapeworm, flukes
Have intermediate hosts for larval development and definitive host for adult form

27. Parasite Medically important Helminths Tapeworm, flatworm Roundworm
Flukes

28. Quick Question Can a virus be a parasite? NO viruses are not living
Parasites ARE living
Can a parasitic worm infect your eyeball?
Obviously.
Are protozoa prokaryotic?
Nope. Eukaryotic
Single-celled eukaryotes

29. Fungi
Multi-cellular fungi have networks of long hollow tubes called hyphae
The hyphae often aggregate in a dense network known as mycelium
The mycelium cluster into a complex structure, known as the fruit
Mushroom is often the name given to the fruit
Yes…mushrooms are fungi.
Fungus is used everyday in foods such as mushrooms, yeast for bread, beer, and drugs

30. Fungi structure

31. Fungi Medically important Fungi Candida albicans
Oral and genital infections
It actually grows as a yeast, but can switch to a multicellular form which infects humans
Called fungal dimorphism
Environmental cues

32. Quick Question What is the order of increasing fungal structure?
Hyphae
Mycelium
Fruit (aka mushroom)

33. Algae
Chiefly aquatic, eukaryotic plant like organisms without true stems, roots, or leaves
Most are autotrophic, photosynthetic, and contain chlorophyll
Produce most of the oxygen in the world available to humans (about 70%)

34. a video about algae oil for fuel