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EXAM 2 MICRO
Viruses
19
Microbiology
Undergraduate 3
10/13/2009

Additional Microbiology Flashcards

 


 

Cards

Term
Step 1: attachment/adhesion
Definition

Virus binds to receptor proteins by ligand protiens which are

 

Phage: tail fibers

Naked: capsomeres

Enveloped: peplomers

Term
Step 2: penetration
Definition

Genetic material enters cytoplasm

 

Phage: lysozyme and contraction of tail capsid remains outside

 

Naked: Phagocytosis, uncoating in cytoplasm (breaking free of vesicle) DIRECT ENTRY

 

Enveloped: Fusion of envelope and cell membrane, phagocytosis, DIRECT ENTRY

 

Term
Step 3: Synthesis
Definition

Host genome may deteriorate (phage, some animal viruses)

 

Genome of virus: directs all cell activities, stops normal activity to produce viral parts

 

2 main molecule types that must be produced during this stage are genome copies and protiens

Term
Step 4: Assembly (maturation)
Definition

Capsomeres put together to form a capsid

 

Genetic material is placed in capsid

 

Enzymes are placed in capsid

 

(Enveloped: peplomers are placed in cell membrane)

Term
Step 5: Release (lysis)
Definition

Phages: Host cell explodes

 

Naked: Host cell explodes

 

Enveloped: Viruses bud out, gain envelope and peplomers

Term

Lysogenic Life cycle

 

Step 3- Incorporation

Definition

Join host cell genome, incorporated viral genes called provirus

 

Trigger activates expression of viral genes

 

Chemical, physical, emotional trauma; age, hormones, imunesystem weak, UV radiation, etc.

Term
Lysogenic viruses associated with cancer
Definition

Dormant/ latent virus- triggered later

 

Persistant infection- continuous release- cell lives

 

Tumor formation- Oncogene activation

Term
Loss of tumor suppressor genes
Definition
Normally ON- funtion to inhibit mitosis in abnormal cells
Term
loss of apoptosis
Definition
Normally ON- function to cause abnormal cells to commit suicide
Term
Angiogenesis
Definition
Normally OFF- function to grow new blood vessels into mass of new cells
Term
Metastasis
Definition
Normally OFF- function to seperate and spread of cells
Term
Mad Cow Disease
Definition

Bovine Spongiform encephalopathy

 

Diagnosis- appearance of brain at autopsy

 

Plaques or fibrous masses of protiens block normal nerve cell movement, brain becomes spongy

Term
Normal occuring proteins
Definition

PrP^c

 

Alpha helix (flexible)

Term
Deformed version of protiens
Definition

PrP^Sc

Beta sheet (flat and stiff)

Term
Scrapie
Definition

found in sheep

 

symptoms: scrape bodies raw by rubbing against fences, posts, etc.  Gradual loss of strength, inability to stand, and erratic behavior

 

Specific Prion Disease

Term
Kuru
Definition

1st human prion disease studied

 

Symptoms: Trembling disease- gradual loss of motor control and death

 

transmitted by cannibalism

 

More common in women and children than men

Term
Creutzfeldt-Jakob disease
Definition

typical disease found in elder humans

 

HEREDITARY

Term
Variant Creutzfeldt-Jakob
Definition

seen in England

 

Younger recipients, no genetic component

 

link to eating beef from BSE infected cows, more specifically, bone-containing cuts of meat.

 

link to head injury

 

PRION DISEASE

Term
Chronic Wasting disease
Definition

Found in North America, transmitted by mule deer, elk, (white tail deer), possibly squirrel population

 

Symptoms:  Body can't absorb nutrients and eats at it's own tissues

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