Microbiology Unit Test Review Flashcards
What is a virus?
A non-cellular particle made of genetic material (DNA/RNA) which can invade living cells.
Examples of viruses:
Covid-19, Influenza, HIV, Measles, Polio, Mumps, Cold Sores, Ebola, etc etc
What is R0? Which virus has the greatest #?
R0 is the basic reproduction rate/number.
(Measles?) has the greatest number.
What is a virus’s ultimate goal? Why is quick host killing bad?
The ultimate goal is to replicate and spread.
Quick host killing is bad because it lessens the virus’ chance of spreading.
What is the hypothesis scientists have about the origin of the virus?
They developed from cellular ancestors and became used to a parasitic way of life. NS favored the loss of cellular parts.
Are viruses alive? Why or why not? State the arguments for both sides.
NO, viruses are NOT alive.
Arguments for NOT ALIVE:
- they are not made up of cells (building block of life)
- relies largely on hosts
- cannot keep themselves stable by homeostasis
- cannot move (not motile)
Arguments for ALIVE:
- can reproduce
- has genetic material
Capsid (function + structure)
holds genetic material, made of protein.
Nuclear acid core (function + structure)
genetic material (DNA/RNA); double helix/half of double helix
Spikes/glycoprotein (function + structure)
unlocks host cells (analogy: key and cabinet lock where the glycoproteins are the keys)
Tail fiber (function + structure)
receptor sites used to recognize specific cells to invade; leads to viral specificity.
Base plate (function + structure)
contains enzymes to cut a hole in the cell wall in order for the genetic material to be “sent” into the host
Envelope (function + structure)
extra protein covering (armour). makes virus less susceptible to changes in temp., acidity and disinfectants
How are viruses categorized?
- whether it has dna/rna
- strain (e.g. “this year’s flu strain is pretty mild”)
Define viral specificity
?
difference between endemic, epidemic and pandemic?
endemic: present in a community at all times; moderate rate.
epidemic: sudden outbreak affecting a certain area; more cases than expected
pandemic: sudden outbreak affecting large regions of the world/worldwide.
what is the difference between antigen and pathogen?
antigen: substances that can trigger an immune response
pathogen: micro-organisms that can cause disease
what are the four jobs of the activated helper-t cell?
- divide rapidly
- activate the cytotoxic t cell
- makes memory t cells
- activates the b cells (specific to the virus)
explain cell-mediated immunity.
- macrophage eats virus by endocytosis
- virus is “digested” and viral antigens are displayed by the macrophage
- helper t-cell is activated.
- helper t-cell divides rapidly
- activates the cytotoxic t cell
- makes memory t cells
- activates (very specific) b-cells
explain humoral immunity
- antigen binds to antibodies
- activated b cells grow and divide rapidly
- b cells produce plasma cells and memory b cells
- plasma cells release antibodies that captures antigens and then kills them
