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29 Cards in this Set
- Front
- Back
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Lytic Cycle: Step 4
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Assembly (Maturation)
Capsomeres form capsids Genetic material in capsid Enzymes in capsid Enveloped: peplomers go to cell membrane |
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Lytic Cycle: Step 5
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Release (Lysis)
Cell releases virus particles Phages: host cell explodes Naked: host cell explodes Enveloped: viruses bud out, gain envelope and peplomers |
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Lysogenic Life Cycle
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Step 1: Attachment
Step 2: Penetration Step 3: Incorporation Step 4: Synthesis Step 5: Assembly Step 6: Release |
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Lysogenic Life Cycle
Step 3: Incorportation |
Viral genes join host cell genome
Incorporated viral genes called provirius Trigger activates expression of viral genes Chemical; physical; emotional truama; age; hormones; immune system weak; UV radiation; AA arginine |
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Animal Virus Options
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Dormant/latent infection- triggered later
Persistent infection- continuous release-cell lives Tumor formation- oncogene activation |
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Viral Connection to Cancer
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Uncontrolled cellular reproduction
Proto-oncogene - (pre-existing) gene converted to oncogene Some viruses seem to activate proto-oncogenes, or act as oncogenes |
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Cancer-Causing Viruses
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Human Papilloma Virus- Genital warts & cervical cancer
Hepatitis B & C Viruses- liver cancer Human Herpes Virus 4- Burkitt's lymphoma (coinfection w/ malaria) Human Herpes Virus 8- Kaposi's sarcoma (coinfection w/ HIV-1) |
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Known Oncogenes
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(tunned OFF or ON to cause cancerous behavior)
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Loss of tumor supressor genes
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Normally ON - inhibit mitosis in abnormal cells
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apoptosis
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Normally ON- cause abnormal cellls to commit suicide
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Angiogensis
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Normally OFF - growth of new blood vessels into mass of new cells
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Metastasis
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Normally OFF - seperation and spread of cells
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Needed about of oncogenes to be threatening
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At least 2 to develop cancerous cells
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Benign
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(Not cancer) tumor cells grow only locally and cannot spread by invasion or metastasis
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Malignant
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(cancer) cells invade neighboring tissues, enter blood vessels, and metastasize to different sites
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Prion Diseases
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Proteinaceous infectious agents
"mad cow disease" Bovine spongiform encephalopathy Diagnosis: appearance of brain at autopsy - Plaques or fibrous masses of proteins block normal nerve cell movement -Brain becomes spongy |
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Molecular Nature of Disease
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Normally occurring proteins (PrPc)
- Alpha helix (flexible) Converted to.. - Deformed version of same proteins (PrPc) - Beta sheet (flat, stiff) |
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Scrapie
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Disease of sleep
Scrape their bodies raw by rubbing against fences, posts Gradual loss strength, inability to stand, erratic behavior |
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Kuru
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1st human prion disease studied
Stanley Pruisner- Nobel Prize for medicine Foré tribe in New Guinea Trembling disease- gradual loss of motor control and death Transmitted by cannibalism - Ritual eating of relatives' remains brains eaten by women and children (most infectous part)- highest rate of disease - Muscle and Skin eaten by men |
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Creutzfeldt-Jakob Disease
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Typical disease- hereditary disease in 50-75 year old individuals
- slow onset (1 year) and death from degenerative brain function loss Varient Creutzfedlt-Jakob seen in England -Same symptoms as typical disease -Younger (23 years old) - No genetic component Linked to eating beef from BSE infected cows? Bone-containing cuts of meat? Link to head injury? |
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Chronic Wasting Disease
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North American prion diseases transmissible to humans
- Mule, deer, elk, (white tail deer?) population - Squirrel population? |
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Bacterial Genetics
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Genetic Variability
- Essential for natural selection - All organisms get Some variability through Mutations |
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Recombination
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new combination of genes
- Eukaryotes - sex accomplishes reproduction and recombination - Bacteria seperate the processes |
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Bacterial Genetics
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Reproduction (binary fission)- vertical gene transfer
Recombination (or new combination of genes existing cell)- horizontal gene transfer |
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Binary Fission
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Reproduce by cloning = No variability
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Bacteria maximize recombination
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Underlying "givens" in how they work:
- foreign DNA always replaces the existing homologous DNA segment - old DNA fragments are recycled (monomers reused) -Result: new genes in old cell!! |
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Plasmids carry genes
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Freely join and leave both:
- The genome - other plasmids "Sticky ends" on plasmids take genes along Plasmids pull out imperfectly, take genes with them to another cell |
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Transformation
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Dead Donor cell
Recipient cell (must be same species) absorbs DNA Replacement/Recycling of homologous DNA |
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Grifis Experiment
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Pneumococcus
- Heat-killed w/ capsule p. cocci- Mouse alive - Live p.c w/ capsule - Mouse dead - Live p.c. w/o capsule - Mouse alive - Heat-killed and live w/o capsule- Mouse dead - Plamids from capsule coded for its production was passed to live non-capsuled p.c. |
