Exam 2 Flashcards
Hepatitis virus
Attacks liver cells
Polio virus
Attacks nerve cells in humans
Viruses tend to be specific
Attacks only certain organisms and certain cells within that organism
Viruses Derived from
Mobile elements in the genome of organisms
components of virus
Nucleic acid: DNA or RNA (Circular or linear; double or single stranded) Protein coat (capsid): one or more proteins
Envelope: lipids, proteins, glycoproteins
Coat and envelope proteins bind to host cell receptors
Viruses that infect bacteria
Bacteriophage
Lysogenic viruses
-Alter characteristics of the bacteria
-Presence of certain chemicals can cause transition from
“Lysogenic cycle” to “lytic cycle”
Retrovirus
In retroviruses, ssRNA (single stranded RNA) is a template for DNA synthesis.
Eg. HIV
Reverse transcriptase
Converts viral RNA to DNA
HIV proteases
Cut poly proteins into functional proteins.
Entry inhibitors
Interfere with the binding between HIV envelope and receptors
Reverse transcript inhibitors
Treatment against HIV
Integrate inhibitors
Prevent integration of viral DNA into the host DNA
Protease inhibitors
Block the activity of a protease enzyme that HIV needs to make new viruses
HIV hides in
Cells of lymph nodes
Processes that contribute to emergence of viral diseases
Mutations
Genetic recombination
E.g. Flu epidemics
& spread of existing virus from one species to another ‘hantavirus ‘
Prions
Infectious proteins
E.g. Mad cow disease, scrapie in sheep in goats, creutzfeldt-Jakob in humans
Prion coverts the normal protein into another prion
Transferred by eating meat with prions
Phylum Arthropoda classes
Chelicerata, Crustacea, Hexapoda, myriapoda
Protostomes include
Spiralia and ecdysozoa
Deuterostomes
Echinodermata and Chordata
