IB BIO HL: Viruses

Virus

submicroscopic infectious agent that replicates only inside the living cells of an organism

Capsid

protective protein coast surrounding genetic material

Bacteriophage

type of virus that infects bacteria

Lytic cycle

process of viral DNA/RNA being injected and destroying host cell (lyses)

Lysis

bursting of host cell

Metabolism

chemical processes that occur within a living organism in order to maintain life

Lysogenic cycle

one of two cycle of viral reproduction in which the virus integrates its genetic material into the host cell’s genome, becoming dormant and replicating along the host cell

Prophage

genetic material of a bacteriophage mixed with an infected bacterium cell

• ex: Bacteriophage Lambda + E. coli cell

Lysogen

bacterial cell that contains a bacteriophage genome

Parasite

an organism that lives in or on an organism of another species and benefits by deriving nutrients at the other’s expense

Obligate parasite

require host cells for replication, includes ALL viruses

Convergent evolution

independent evolution of similar features in species of different periods in time

Antibodies

blood protein produce in response to and counteracting a specific antigen, activates immune system

Antigens

a toxin or other foreign substance which induces an immune response in the body, especially the production of antibodies

Immunity

state of quality of being resistant to a particular infectious disease or pathogen

Mutation

change in the DNA sequence of an organism

Antigenic drift

an GRADUAL change to the HA (hemagglutinin antigen) and NA (neuraminidase antigen) surface proteins of the influenza virus

Antigenic shift

an ABRUPT major change to the HA (hemagglutinin antigen) and NA (neuraminidase antigen) surface proteins of the influenza virus