1. Introduction to Microorganisms Dr. Jackson

2. Objectives
Differentiate the five major types of microorganisms based on common characteristics such as size, structure, mode of reproduction, and method of obtaining nutrients.
Drill
Using the following pictures, what do you think are the following microorganisms?

3. The rod-shaped bacterium Haemophilus influenzae, one of the bacterial causes of pneumonia

4. Pilobolus, a mold, which is a type of fungus, with its sporangia oriented toward the light. When released, the sporangia will stick to grasses and be eaten by grazing animals

5. An amoeba, a protozoan, approaching food

6. The algae, Characiosiphon

7. T4 bacteriophage (virus that attack bacteria)

8. Bacteria (singular: Bacterium)
Simple, single-celled (unicellular) organisms
Genetic material is not enclosed in a nuclear membrane – prokaryotic

9. Bacteria (singular: Bacterium)
Appear in one of several shapes
Bacillus – rodlike
Coccus – spherical or ovoid
Spiral – corkscrew or curved
Can be star-shaped or squared
Individual bacteria may form pairs, chains, clusters, or other groupings

10. Bacteria (singular: Bacterium)
Enclosed in cell walls that are largely composed of a substance made up of sugars and amino acids called peptidoglycan

11. Bacteria (singular: Bacterium)
Reproduces asexually by dividing into two equal daughter cells in a process called binary fission

12. Bacteria (singular: Bacterium)
For nutrition
Most use organic chemicals, which can be derived from either dead or living organisms
Some manufacture their own food by photosynthesis
Some can derive nutrients from inorganic substances

13. Bacteria (singular: Bacterium)
Many can “swim” by using moving appendages called flagella

14. Let’s Review Are bacteria unicellular or multicellular?
Are bacteria prokaryotic or eukaryotic?
Name the three major basic shapes of bacteria.
What is the cell wall composed of in most bacteria?

15. Let’s Review (cont.)
What is the name of the process by which bacteria divide?
What structure allows bacteria to move?
Name two ways bacteria can get food.

16. Fungi (singular: fungus)
Eukaryotes – organisms whose cells have a nucleus containing DNA and surrounded by a nuclear membrane

17. Fungi (singular: fungus)
May be unicellular or multicellular
Large multicellular fungi, such as mushrooms, may look like plants, but cannot carry out photosynthesis and have cell walls composed of a substance called chitin
Unicellular form are yeasts, which are oval microorganisms larger than bacteria

18. Fungi (singular: fungus)
Most typical fungi are molds
Form visible masses called mycelia, which are composed of long filaments called hyphae that branch and intertwine
Cottony growths sometimes found on bread and fruit are mold mycelia

19. Fungi (singular: fungus)
Can reproduce sexually or asexually
Obtain nutrients by absorbing solutions or organic material from their environment (soil, seawater, water, or animal/plant host)

20. Let’s Review Name three types of fungi.
Are fungi prokaryotic or eukaryotic?
Are all fungi unicellular or multicellular?
Do fungi reproduce sexually or asexually?
How do fungi obtain nutrients?

21. Protozoa (singular: protozoan)
Unicellular and eukaryotic
Move by
Pseudopods (false feet) – extensions of their cytoplasm
Flagella – long tail
Cilia – numerous short hair-like appendages
Variety of shapes

22. Protozoa (singular: protozoan)
Live either as free entities or as parasites (organisms that derive nutrients from living hosts)
Absorb or ingest organic compounds from their environment
No cell wall
Reproduce sexually or asexually

23. Let’s Review Are protozoa unicellular or multicellular?
Are protozoa prokaryotic or eukaryotic?
Do protozoa have cell walls?
Do protozoa reproduce sexually or asexually?
How do protozoa obtain nourishment?

24. Algae (singular: alga)
Photosynthetic eukaryotes with a variety of shapes and both sexual and asexual forms
Can be unicellular or multicellular
Cell walls composed of cellulose

25. Algae (singular: alga)
Abundant in fresh and salt water, in soil, and in association with plants
Need light and air for food production and growth, but do not generally require organic compounds from the environment
Produce oxygen and carbohydrates, which are used by other organisms
Play an important role in the balance of nature

26. Let’s Review Are algae unicellular or multicellular?
Are algae prokaryotic or eukaryotic?
Do algae reproduce sexually or asexually?
By what process do algae obtain nutrients?
What do algae produce that can be used by other organisms?

27. Viruses So small, they can only be seen with an electron microscope
Acellular (not cellular)

28. Viruses
Structurally simple – a virus particle that contains a core is made up of
One type of nucleic acid, either DNA or RNA
A protein coat
A lipid membrane called an envelope
Reproduce only by using the cellular machinery of other organisms
All are parasites of other forms of life

29. Let’s Review Are viruses unicellular or multicellular?
What are the three parts of a virus?
How do viruses obtain nutrients?
Can viruses reproduce by themselves?