Microbio Exam 3

Hierarchy of life

Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species.

3 Classes in Firmicutes Phylum

Clostridia

Mollicutes

Bacilli

(Low G + C)

Low G + C Gram-Positive Bacteria: Clostridium (Fermicutes-Costridia)

Rod-shaped, obligate anaerobes

Important in medicine & industry

Clostridium botulinum/tetani/perfringes/difficile

Low G + C Gram-Positive Bacteria: Mycoplasma (Fermicutes-Mollicutes)

PLEOMORPHIC: Lack cell walls

Smallest free-living cells

Colonize mucous membranes of the respiratory and urinary tracts

(Ex. Mycoplasma pneumoniae)

Low G + C Gram-Positive Bacteria: Bacillus (Fermicutes-Bacilli)

Bacillus - make endospores and toxins

Ex. B. thuringiensis: toxin used by farmers and gardeners as an insecticide (caterpillars)

Ex. B. anthracis: produces anthrax toxin

-Spores used as bioweapon

High G + C class in Firmicutes Phylum

Actinobacteria

Mycobacterium

Gram-Negative Proteobacteria

-Largest and most diverse group of bacteria

-Many contain prostheca

Prostheca: For adhesion/attachment and increase surface area for absorption

5 classes:

Alpha, Beta, Gamma, Delta, Epsilon

Prostheca

For adhesion/attachment and increase surface area for absorption

In Proteobacteria

Nitrogen fixers (N2 to NH3)

Grow in association with plant roots

Azospirillum

Rhizobium

Nitrifying bacteria (NH3 to NO3)

Nitrobacter

Brucella

Causes brucellosis

Source is unpasteurized dairy product, meat

Enterobacteriacea

Escherichia (Gastroenteritis)

Enterobacter (Rarely pathogenic)

Serratia (Rarely pathogenic)

Salmonella (Enteritis)

Proteus (UTI)

Shigella (Shigellosis)

Yersinia (Plague)

Klebsiella (Pnemonia)

Bdellovibrio

Vampire-bacteria

A gram-negative infects other Gram-negative bacteria

Myxobacteria

Deltaproteobacteria with multicellular-like behavior

Move by gliding

Soil-dwelling and form stalked fruiting bodies

Contain resistant, dormant myxospores that can survive for a decade or more

Epsilonproteobacteria (rods, vibrios, or spirals): Campylobacter

Causes blood poisoning and inflammation of the intestinal tract

Epsilonproteobacteria (rods, vibrios, or spirals): Helicobacter

Causes ulcers

Chlamydias

Intracellular obligate parasites

Most common ST bacteria in the United States

Spirochetes

Motile helical bacteria which move in a corkscrew motion

ENDOFLAGELLA

Treponema (syphilis)

Borrelia (Lyme disease)

Bacteroides

Inhabit digestive tracts

Some species cause infections

Cytophaga

Aquatic, gliding bacteria

Important in the degradation of raw sewage

Treatment of sewage before release in waterways

Mitosis

1) Cell partitions replicated DNA equally b/w 2 nuclei

2) Maintains ploidy of parent nucleus

DIPLOID PRODUCES DIPLOID

3) Four phases

• Prohase

• Metaphase

• Anaphase

• Telophase - Cytokinesis

(cytoplasmic division) 1 cell becomes 2 cells

Meiosis

1 cell becomes 4 cells called gamete with mixed genetic info (unequal)

Diploid nuclei produce haploid daughter nuclei

Two stages- meiosis I and meiosis II

**Tetrad Formation

What is unique to meiosis?

Tetrad Formation in prophase I:

Involves crossing over and exchange of genetic information b/w chromosomes

Tetrad(two homologous chromosomes, four chromatids)

Crossing over

Different types of cytoplasmic division

Plant cells = cell plate

Animal cells = cleavage furrow

After mitosis (telophase, cytokinesis)

Schizogony

Cytokinesis is delayed

Multinucleated cells seen

E.g. malaria

(Special type of division seen in some)

6 groups of protozoa

Parabasala

Diplomonadida

Euglenozoa

Alveolates

Amoebozoa

Rhizaria

Parabasala

Contain parabasal body: Golgi body-like structure

Contains hydrogenosomes (like mitochondria)

(Typical mitochondria is absent)

Trichonympha

Trichomonas

Alveolates

Have membrane-bound cavities called alveoli

Ciliates

Apicomplexans

Dinoflagellates

Apicomplexans

Apical complex- Complex of organelles allow them to penetrate host cells

Obligate endoparasites

Malaria

Plasmodium

Toxoplasma

Atovaquone

interferes with electron transport in protozoans which cause malaria and toxoplasmosis

Dinoflagellates

Unicellular microbes with photosynthetic pigments

Motile dinoflagellates have 2 flagella

**forms large portion of freshwater and marine plankton- support food chain and life

***abundance causes red tide - produce neurotoxins

(Historically classified as algae)

Rhizaria

Amoebae with shells that move and feed with thread-like pseudopods

Radiolaria: Have ornate shells of silica (glass-like)

Foraminifera: Have ornate shells of calcium carbonate

Both constitute the marine zooplankton

Mycorrhizae (symbiotic fungus)

Help plants absorb water and minerals

Fungus 2 basic shapes

Hyphae (moldlike shape) tube

Single celled (yeastlike shape)

and mixed

Lichens (grows on rock)

Partnerships between

1) Fungi

• provides nutrients, water, and protection

2) Photosynthetic microbes

• provides carbohydrates and oxygen

Create soil from weathered rocks

Eaten by many animals

Chrysophyta

Golden algae, yellow-green algae, and diatoms

Most are marine algae - phytoplankton

(GIVE OXYGEN) Diatoms: silica frustules

Cell wall - cellulose and silica

Water molds

Differ from fungi:

• Have tubular cristae in their mitochondria

• Cell walls are of CELLULOSE instead of chitin

RECYCLERS IN WATER- Decompose dead animals and return nutrients to the environment

Ex. some pathogenic caused Irish potato famine

Characteristics of viruses

Acellular

Cannot carry out metabolic pathway/reproduce independently

No cytoplasmic membrane, cytosol, organelles

Contain either DNA or RNA