Viruses PDF

VIRUSES! D: Viruses are…. ◦ Smaller than BACTERIA and ANIMAL CELLS ◦ NOT CONSIDERED LIVING FOR TWO REASONS! 1.) NEED a HOST (living cell) in order to continue REPLICATING! 2.) Can’t METABOLIZE (break down) food for ENERGY. VIRUSES ARE MADE UP OF…. ◦NUCLEIC ACIDS (DNA OR RNA) ◦PROTEIN COAT (als...

VIRUSES! D: Viruses are…. ◦ Smaller than BACTERIA and ANIMAL CELLS ◦ NOT CONSIDERED LIVING FOR TWO REASONS! 1.) NEED a HOST (living cell) in order to continue REPLICATING! 2.) Can’t METABOLIZE (break down) food for ENERGY. VIRUSES ARE MADE UP OF…. ◦NUCLEIC ACIDS (DNA OR RNA) ◦PROTEIN COAT (also know as a CAPSID) ◦The PROTEIN COAT IS USED FOR ATTACHMENT TO HOST! Protein Coat (Capsid) Nucleic Acid (DNA or RNA) In order to attach to the cell, the Cell’s RECEPTORS and the Virus’ PROTEINS NEED TO MATCH! 2 REPLICATION CYCLES 1.) LYSOGENIC (LONGER) 2.) LYTIC (SHORTER) Lytic (Remember this is SHORTER) 1.) Virus INFECTS a 2.) New virus parts 3.) The new viruses living cell! begin to ASSEMBLE DESTROY the cell inside the cell! (OR LYSE IT)! Lysogenic (Remember this word is LONGER, so this is the LONGER Cycle) 2.) The VIRUS’ DNA COMBINES with the HOST CELL’s DNA! The VIRUS’ DNA IS INACTIVE HERE (it 3.) The cell continues to won’t harm the cell). replicate normally! THE LYSOGENIC CYCLE CAN BE BAD WHEN…. ◦ The VIRAL NUCLEIC ACID BECOMES ACTIVE! :o ◦ It becomes ACTIVE when the VIRAL DNA and the HOST CELL’s DNA SEPARATE. ◦ This can LEAD TO THE LYTIC CYCLE ANTIOBIOTICS vs. VACCINES ◦Antibiotics CANNOT kill viruses! They can ONLY kill bacterial diseases! ◦HOWEVER, we can PREVENT some viruses by using VACCINES  HIV ◦Causes AIDS! ◦Attacks your helper T-CELLS (which are part of your IMMUNE SYSTEM) ◦This virus changes (OR MUTATES) SO FAST, that it’s IMPOSSIBLE for us to develop a VACCINE against it!  The virus begins to kill all the TCELLS until there are NONE LEFT! HIV OO D T-CELLS HIV The body is unable to defend itself against infections!