Transcript 08/22/08

Life
• Individual survival
– Take in, digest nutrients
– Eliminate wastes
– Recognize self from non-self
– Recognize enemies
– Repair damage
• Reproduction
– Survival of species
– Gene transfer
US
Vertebrates
Invertebrates
Plants
Animals
Archaea
Bacteria
UCA
Prokaryotes
Single-celled
Protozoa
Eukaryotes
Algae
Fungi
Cell Functions
• Maintenance
– Recovery of energy from nutrients
– Storage of energy
– Synthesis of correct proteins and other cell
components
• Perpetuation of self
– DNA replication
– Cell division
• Specialized functions
– e.g. muscle, blood, nerve cells, immune system
The molecules of life
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Nucleic acids (DNA, RNA)
Proteins
Carbohydrates
Lipids
Lipoproteins, glycoproteins, vitamins….
Genomics
The Genome
Transcriptome
Transcription
DNA
RNA
DNA + DNA
DNA Replication
Cell division
Translation
Protein synthesis
Protein
The Proteome
Proteomics
PROTEINS
• Chains of amino acids
• Structural elements –
– cell walls, membranes
• Transport
• Catalysts - enzymes
• Communication - within cells, between cells
• Cytokines
• Signal transduction factors
• Receptors
• Vital for regulation of growth, cell division
Schematic metabolic cycle
Cellular components
Nucleic acids, Carbohydrates,
Protein, Fat
Food
Metabolic
intermediates
Carbohydrates,
Fats, Glucose,
Proteins
NADP+
ADP + Pi
ATP
ATP
NAD+
NAD+
NADH
Wastes
CO2, H2O,
lactic acid
NADH
ADP +
Pi
NADPH
Work
Transport
Assembly
Movement
Heat
The Metabolome - Metabolomics
Viruses
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0.02-0.3 micrometers diameter
Genetic material: ss or ds DNA, RNA
Protein coat
Some enzymes
Lipid envelope – enveloped/non enveloped
viruses
• Nomenclature semi-systematic
– Hepatitis A Virus, HAV
• Need host cell for replication
The plasma membrane
Lipid bilayer
Glycoprotein
Av. Width
Glycolipid
Sugar
7.5 nm
Polar
(75 Å)
Non-polar
(Lipid)
Protein
The Flu Virion
Hemagglutinin
Matrix protein
Neuraminidase
Lipid bilayer envelope
• Envelope: lipid bilayer membrane +
glycoproteins, typically acquired from
host cell membranes
• Capsid (protein coat): multiple copies
of 1 or more proteins in an array
Life-cycle of virus
• Particle, virion
• Infects host cell
• Genetic material uses host’s replication
apparatus to produce new viral
components (capsid, core proteins,
genetic material)
• Components assemble into viral particles,
exit host cell, sometimes lysing host cell
• Each type of virus has its
own specific host
• Viruses that colonize
bacteria are
bacteriophage viruses
(bacteriophages).
www.virustaxonomyonline.com
Viruses in the Environmment
• Must be able to survive outside host cell
• Non-enveloped viruses are more persistent than
enveloped viruses
– Lipid envelope more easily damaged, protein
coat confers stability
• Enteric viruses are almost all non-enveloped
– Hepatitis A, poliovirus, noroviruses,
rotaviruses
– Transmitted by direct and indirect contact,
fecally contaminated water, food, fomites and
air.
• Respiratory viruses, mostly enveloped
• adenoviruses, coronaviruses, rhinoviruses,
influenza viruses,
• Transmitted by direct and indirect contact, air
(aerosols) and fomites (some also by water and
food).
Unicellular organisms
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Bacteria - procaryotes
Protozoa
Algae
- eucaryotes
Fungi
Procaryotic Cell (left) and Eucaryotic Cell (right)
Procaryotes: Bacteria and Others
Unicellular organisms
Simple internal organization
Multiply by binary fission
Diameter ~0.5-1.0 micrometer
Envelope: cytoplasmic membrane, cell wall &
capsule (polysaccharide)
Some have appendages:
flagella: for locomotion
pili: attachment to other cells for genetic transfer;
virus receptor site
Standard Linnean nomenclature: Genus species
Diverse bacteria
Gram positive
Gram negative
More bacterial types
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Aerobes
Anaerobes
Facultative aerobes
Rods (bacilli)
Spherical (cocci)
Comma-shaped (vibrios)
Spiral (spirochetes)
Bacteria in the Environment
Some bacteria form spores:
– highly resistant to physical and chemical
agents and
– very persistent in the environment
Unicellular Eucaryotes:
• More complex
internal
organization:
– organelles:
discrete nucleus,
mitochondria
• Wide range of
sizes: 2 micrometers
and larger
Protozoa
• Unicellular; non-photosynthetic; flexible cell
membrane; no cell wall; some are parasites,
have complex life-cycles
• Wide range of sizes and shapes; 2 micrometers
to 2 mm
• Disease-causing:
– Amoebae: Entamoeba histolytica
– Flagellates: Giardia lamblia
– Ciliates: Balantidum coli
– Sporozoans: Plasmodium vivax
– Coccidians: Cryptosporidium parvum
– Microsporidia: Cyclosopora cayetanensis
Cryptosporidium parvum oocysts: ~5 m diameter
Wet mount by
differential
interference contrast
microscopy
Acid fast stain of fecal
preparation
Giardia lamblia cyst: ~10 x 8 micrometers
More Protozoans: Fungi
Fungi (yeasts and molds):
•non-photosynthetic
• immotile;
•rigid cell wall
Molds:
•grow as branched, interlacing
chains or filaments (hyphae)
called mycelia
Mitospores (conidia) of
Penicillium, one of the
asexual Ascomycota
•Yeasts:
• do not form mycelia
•grow as single cells that bud
•sexual reproduction possible
Yeasts
Algae
• Photosynthetic
• Rigid cell wall
• Simple plants, protists,
protozoa, plancton, derived
from cyanobacteria ?
• Wide range of sizes and
shapes
– 2 micrometers and larger
• Some algae are harmful
– Algal booms
• Toxins
– Anabaena, anatoxins
Nostoc
Helminths (Worms)
• Multicellular animals
• Some are human and/or animal
parasites
• Eggs pass via human and animal
excreta to water, food, soil.
• Several major groups:
– Roundworms, Nematodes eg.
Ascaris, Trichinella spiralis,
hookworms
– Flatworms Platyhelminthes:
Cestodes (tapeworms): pork,
beef tapeworms, and
Trematodes (flukes) eg
Schistosomes
– Annelids (leeches)
Necator (hookworm)
eggs
adult
• Eggs hatch in soil
• Infective stage: larvae
• Penetrate skin, migrate to
blood, lungs, trachea
• or are ingested
• Adults mature in intestine
• Attach to intestinal walls
– anemia
– Necator americanus ,
Ancylostoma duodenale
(hookworm)
Trematodes
• Schistosomes (blood
flukes)
• Liver fluke
Cestodes
• Head (scolex)
attaches to tissue
– beef tapeworm, Taenia
saginata
– pork tapeworm (T.
solium)
• Grows in intestine
http://www.marvistavet.com/html/body_tapeworm.html
Multicellular organisms
• Plants
• Animals
– Invertebrates
– Vertebrates