Transcript Chapter 19 Bacteria & Viruses

Chapter 19 Bacteria &
Viruses
19.1 Prokaryotes
 Single-celled
 Lack
nucleus
 Smallest, most common microorganism
Classification
E. Coli bacteria
 Eubacteria
(D/Bacteria)
 Larger kingdom; greater diversity
 Cell wall w/peptidoglycan (carbo)

Shapes
 Archaebacteria
(D/Archaea)
 Extremist (anaerobic methanogens)
 Cell wall w/out peptidoglycan
 DNA sequence of key genes = eukaryotes
Billion yr old cyanobacteria
Bacteria in hot springs
Identification
 Shapes
 Bacilli: rod-shaped
 Cocci: spherical


Streptococcus: chains
Staphylococcus: clusters
 Spirilla: spiral-shaped
Streptococcus
Staphylococcus
 Cell
Walls
 Gram + : single layer; stain purple
 Gram - : double layer; stain pink (disease)
 Movement
 Flagella: whip-like structure
 Energy
 Autotrophs (make food)


Photoautotrophs: cyanobacteria (aerobic)
Chemoautotrophs: anaerobic
 Heterotrophs (obtain food)
Cyanobacteria
 Respiration
 Obligate aerobes: respire/need O2
 Obligate anaerobes: ferment/killed w/ O2

(C. botulinum)
 Facultative anaerobes: resp/ferm
Flesh eating bacteria
C. botulinum produces the potent
nerve toxin that causes botulism.
Tetanus
 Reproduction
 20 min doubling time
 Binary Fission: Asexual reproduction
 DNA
replicated & divides
 Identical daughter cells
 Conjugation: Sexual reproduction
 Genetic
material exchange
 Protein bridge forms between bacteria (pilli)
 Endospore
 Internal
wall enclosing DNA/cytoplasm
 Remains dormant (months to centuries)
19.2 Bacteria in
Nature
 Decomposers
 Recycle nutrients
 Sewage treatment
 Nitrogen
Fixation
 Fixing N2 (air) to NH3 (ammonia=fertilizr)
 Plants need N for AA to make proteins
 Disease
 Pathogens
 Tissue
damage: tuberculosis (lungs)
Table 19.6 Tissue specificity as a factor in infectious disease
Tissue infected
Organism
Diphtheria
Throat epithelium
Corynebacterium
diphtheriae
Gonorrhea
Urogenital epithelium
Neisseria gonorrhoeae
Cholera
Small intestine
epithelium
Vibrio cholerae
Pyelonephritis
Kidney medulla
Proteus sp.
Dental caries
Oral epithelium
Streptococcus mutans,
S. sobrinus, S. sanguis,
S. mitis
Spontaneous abortion
(cattle)
Placenta
Brucella abortus
Acquired
immunodeficiency
syndrome (AIDS)
T helper lymphocytes
Human
immunodeficiency virus
(HIV)
Malaria
Blood (erythrocytes)
Plasmodium sp.
Disease
 Toxins:
salmonella, tetanus, botulism
Botulism: no contraction
(death by respiratory failure)
Tetanus: permanent contraction
(death by respiratory failure)
 Vaccines: stimulate immune system
 Antibiotics: block growth/reproduction
 Human
Uses
 Food; Industrial; Genetic engineering
Daniel Bond, from the University of Massachusetts,
Amherst, helped create a battery that uses
common
bacteria to turn organic matter from the ocean floor
nto electricity. In May he will move his laboratory to
the University of Minnesota, where he will work with
other faculty on renewable energy.
Bacteria products for
biological filters
Solid waste digester takes solid
organic waste and uses bacteria to
turn it into methane, which is then
used to generate electricity.
BLOCKING OUT GAS.This wastewater-treatment tower
bacteria-covered foam blocks (inset) to eliminate the
hydrogen sulfide bubbling from treated sewage.
 Controlling
 Sterilization: Heat; Disinfectant
 Food: Refrigerate, heat, seal, preserve
19.3 Viruses
 What
is it?
 Non-living; lack cells; need host to reproduce
 Smaller/simpler than smallest cells
 DNA/RNA core; protein coat (capsid)
 Infection
 Species specific (bacteriophage = only
bacteria)
 Lytic: host cell destroyed
 Virus
enters host (DNA/RNA injected)
 Replicates using materials of host DNA
 Host burst and releases many new virus
Lytic Viral Reproduction Phase
 Lysogenic: uses host indefinitely
 Virus
embeds DNA (prophage) into host DNA
 Replicated w/ host DNA
 Will eventually becomes lytic
Lysogenic Phase
 Disease
 Vaccines: must receive before infection
 Cancer: oncogenic virus
 Disrupt
cell growth/division
 Retrovirus: contain RNA
 DNA
copy made and inserts into host DNA
 RNA to DNA (backwards)
 AIDS