Microbiology Review

Biology IIBiology II

The Inner Life of the Cell

• See and Hear Video See and Hear Video showing modeled showing modeled

behavior of cellular life…behavior of cellular life…

Microbiology

The study of single celled The study of single celled organisms smaller than organisms smaller than 11mmmm in size with most in size with most being too small to be seen being too small to be seen with the naked eyewith the naked eye..

History of Human Knowledge

•Used in foods for thousands of Used in foods for thousands of yearsyears

•First described 1684 by First described 1684 by

van Leeuwenhoekvan Leeuwenhoek

•Germ Theory of Disease Germ Theory of Disease developed by developed by KochKoch in the late in the late 1800’s1800’s

What Makes a Cell?

• Smallest entity capable of independent Smallest entity capable of independent life.life.

• Separated from the environment by a Separated from the environment by a cell envelope.cell envelope.• Always a cell membrane.Always a cell membrane.• Sometimes includes a cell wall (in plants).Sometimes includes a cell wall (in plants).

• Contain internal structures.Contain internal structures.

Who are These Guys?

• AlgaeAlgae• ProtozoaProtozoa• FungiFungi• ArcheabacteriaArcheabacteria• VirusesViruses• Prions and ViroidsPrions and Viroids• BacteriaBacteria

Algae • Eukaryotes that may be unicellular, Eukaryotes that may be unicellular,

colonial or filamentous.colonial or filamentous.

Algae• Aquatic or terrestrial. Aquatic or terrestrial. • Mostly plant-like characteristics.Mostly plant-like characteristics.• Photosynthetic.Photosynthetic.• Great variety of types, but all Great variety of types, but all

contain chlorophyll.contain chlorophyll.• Some animal-like characteristics Some animal-like characteristics

like phagocitosis of other like phagocitosis of other organisms.organisms.

Algae

Netrium (algae)

Algae

Cladophora Algae

Protozoa• Single celled eukaryotes, but may Single celled eukaryotes, but may

form colonial aggregates.form colonial aggregates.• Aquatic with animal-like Aquatic with animal-like

characteristics.characteristics.

Paramecium

Amoeba

Protozoa• Ingest organic matter for nutrients.Ingest organic matter for nutrients.• Vary greatly in size from 0.003mm Vary greatly in size from 0.003mm

to 5mm.to 5mm.• Many are human parasites.Many are human parasites.• Most are motile.Most are motile.

key innovation: phagocytosis

Protozoan Feeding

Raptorial Feeding: direct interception of prey

Volvox

Paramecium

Stentor

Amoeba

Vorticella Colony

Fungi• Very diverse group of eukaryotes. Very diverse group of eukaryotes. • Not all are microbes (mushrooms).Not all are microbes (mushrooms).• Yeasts are unicellular and spherical.Yeasts are unicellular and spherical.• Molds are filamentous with branching.Molds are filamentous with branching.

Fungi

•Non-photosynthetic.Non-photosynthetic.•Require the uptake of organic Require the uptake of organic

matter for nutrients.matter for nutrients.•Saprophytic (feeds on dead Saprophytic (feeds on dead

matter) or parasitic (infects the matter) or parasitic (infects the living).living).

•Propagate by spores.Propagate by spores.

http://upload.wikimedia.org/wikipedia/commons/c/ca/Fuzzy_Fungi_%28Schizophyllum_commune%29.jpg

Archeabacteria• Single celled Single celled

prokaryotes. prokaryotes. • Extremophiles.Extremophiles.• 4 broad groups.4 broad groups.

• Halophiles (like salty Halophiles (like salty environments)environments)

• Methanogens Methanogens (like (like swampy environments)swampy environments)

• Sulfur dependentSulfur dependent• Thermophiles (like it Thermophiles (like it

very hot)very hot)

Archeabacteria

Viruses• Consist of nucleic acid and Consist of nucleic acid and

protein.protein.

Viruses

• Obligate intracellular parasites Obligate intracellular parasites (can only live within other cells)(can only live within other cells)

• Are they really alive?Are they really alive?

• In general, are smaller than most In general, are smaller than most prokaryotes.prokaryotes.

Prions and Viroids

• PrionsPrions are proteins that cause diseases are proteins that cause diseases like BSElike BSE (Bovine Spongiform Encephalopathy, (Bovine Spongiform Encephalopathy, commonly known as 'mad cow disease').commonly known as 'mad cow disease').

• ViroidsViroids are small RNA’s with no are small RNA’s with no associated protein that causes diseases associated protein that causes diseases in plants.in plants.

• Neither fit the criteria for living Neither fit the criteria for living organisms, but they are microbes and are organisms, but they are microbes and are therefore studied by microbiologists.therefore studied by microbiologists.

Bacteria• Ubiquitous (they’re everywhere!)Ubiquitous (they’re everywhere!)

Bacteria• Reproduce asexually by fission or Reproduce asexually by fission or

sexually by conjugation.sexually by conjugation.• Vary greatly in shapes, sizes, Vary greatly in shapes, sizes,

metabolisms, and growth metabolisms, and growth conditions. conditions.

• Some main characteristics used in Some main characteristics used in identification are colony identification are colony appearance and cell size, shape, appearance and cell size, shape, physiology and metabolism.physiology and metabolism.