BACTERIA, PROTISTS, FUNGI, AND VIRUSES... PATHOGENS BACTERIA, PROTISTS, FUNGI, AND VIRUSES...

PROKARYOTAE; aka Bacteria… Prokaryotic (no nucleus) Genetic code; one single circular strand of DNA Plasmids are DNA outside the chromosome No membrane bound organelles They do have ribosomes Cell wall made of an amino-sugar called peptidoglycan Pili are hair like appendages on outside of the bacteria; for attachment and reproduction

Structure…

Metabolism… Most are heterotrophs Autotrophs; make their own food Feed off dead organic matter, symbiotic, and parasitic Autotrophs; make their own food Photosynthetic Chemosynthetic

Respiration… Obligate aerobes; need oxygen Obligate anaerobes; oxygen kills them Facultative anaerobes; with or without oxygen

REPRODUCTION Asexual = binary fission (mitosis) Sexual = conjugation; uses pili Can reproduce as quickly as 20 minutes

BACTERIA CAN EXCHANGE GENETIC MATERIAL!!! Plasmid: giving a chunk of DNA Conjugation: swapping DNA via “pili”

Transfer of DNA… Conjugation

Classification by Shape Bacillis = Rod shaped Coccus = Spherical Spirillum = Spiral Shaped

SHAPES Coccus Spirillum Bacillus

Classified by Organization… Strep Staph Diplo

Classified by Cell Wall Structure… Gram Positive = Two layer membrane Thick peptidoglycan cell wall Plasma membrane under the cell wall Purple Gram Negative = Three layer membrane Thin peptidogycan cell wall Lipid membrane > petidoglycan cell wall > plasma membrane Pink

Gram Positive vs. Gram Negative…

BACTERIA: THE GOOD, THE BAD, THE UGLY… Bacteria can be pathogens… Anthrax, tetanus, scarlet fever, strep throat… Bacteria can be useful… Nitrogen fixing; helps plants survive Degrades wastes Alternative energy sources Produce plastics Source of possible medicinal drugs

VIRUSES…

Characteristics… Nucleic acid core; either DNA or RNA but never both Capsid; protein coat surrounding the nucleic acid core No ribosomes or organelles of any kind No metabolism (doesn’t eat or breath) Host cell reproduces the virus

Structure…

Infection cycle… Lytic Cycle; Attachment of virus on cell membrane Injection of DNA or RNA into cytoplasm Cell replicates virus RNA or DNA Assembly of viral structure (capsid & DNA) Release; cell bursts and viruses escape

Lytic Cycle

Other ways… Lysogenic Cycle Virus attaches Viral DNA is injected into cell Viral DNA is incorporated into host DNA Cell divides and daughter cells contain the viral DNA; process continues May go into lytic cycle (scary)

Lysogenic cycle…

Retro-viruses Retrovirus is a virus that contains only RNA. Virus has its own reverse transcriptase, an enzyme that makes DNA from RNA. New DNA molecule is incorporated into the hosts DNA. Example: HIV

HIV

HIV Anatomy

HIV Genes

HIV Gene Expression

HIV Infection Lytic cycle Viral load usually large enough at 6 months after infection to test positive on ELISA or viral load tests Contracted through blood transfusions, mothers milk, unprotected sexual contact, dirty needles…affects ALL ages, races, and genders!

Retrovirus…

HIV Therapies Docking Proteins (CD-4) Reverse transcriptase (block action) Proteases block building of Virus Proteins Integrases block integration of vDNA into host DNA AZT prematurely ends viral DNA replication Natural Immunities (CD-4 altered or super immunity) Other? (vaccine?)

Viruses: The Good, The Bad, The Ugly… Viruses can be pathogens… HIV, Influenza, Herpes, Chicken Pox… Linked to cancer: Mono, Herpes, Hepatitis Germ warfare: small pox Viruses can be useful… Can be used to inject useful genetic codes Example; bacteria produce insulin Vaccines; polio, measles, hepatitis…

Protists…

PROTISTA (protozoans) Eukaryote (has nucleus and membrane bound organelles) Single-celled Two major categories Protists Blue-green algae

Are they plants? Animals?? Fungi??? Some protists are plant like! Blue-green algae are photosynthetic and are the basis for aquatic food chains Protists are animal like! Carnivorous (ex. paramecium) Parasitic (ex. Plasmodium) Protists are like Fungi too! Slime molds digest decaying logs and leaves

Protists: The good, the bad, the ugly… Good: Form the basis of food chains Ex. Algae Bad: Can cause crop damage Ex. Slime molds Ugly: Cause serious disease Ex. Malaria and Giardia

Giardia life cycle…

Giardia…

Malaria life cycle…

Malaria…

Fungi…

Fungi are biologically “weird”… May be one simple cell or millions. Have cell walls but are made of sugar. Organelles can move from one cell to another They can’t move nor can they make their own food. They digest food outside themselves then absorb it through their cell walls. Can reproduce sexually or asexually

Structure of Multicellular Fungi… Cell Wall: Made of chitin, a complex polysaccharide (sugar). Hyphae: Threadlike filaments that develop from fugal spores. Mycelium: Network of hyphae. Anchor fungi, invade host cell, and reproductive structures Septa: divide hyphae into individual cells Porous, cytoplasm and organelles can move freely.

Hyphae Mycelium

The Septa…

Reproduction… Fragmentation: hyphae are severed and grow into new mycelium Ex. Shoveling in a garden Budding: Single celled fungi splits in two Ex. Yeast Spores: hyphae grow away from fungi and produce a case containing spores Ex. Mushrooms

Classified by eating habits Saprophytes: Feed off dead plants and animals. Ex. Bread mold, mushrooms, bracket fungi. Symbionts: Live with other organisms, mutual benefit. Ex. Lichen (fungi outside, algae inside) Parasites: Live off live organisms Ex. Cause of Athletes Foot, Ringworm, etc.

Fungi; The good, the bad, the ugly… Good: decompose organic material, make antibiotics (penicillin). Bad: destroys food, wood products, shower curtains, etc… Ugly: Pathogenic (yeast infection, athletes foot, ring worm, etc.)

Ring worm…

Athletes foot…

Questions???