W1 - discussion questions Flashcards
1a. What information do we need to determine the type of microorganism
if all we see if a picture of a round object?
= Size.
bacteria = micro meters
You can see bacteria, fungi etc. under a microscope and are measured in micrometers.
viruses = nano meters
Viruses cannot be seen under a microscope as they are measured in nanometers.
1b. What might we look for to tell if it is a
round bacteria or a round yeast?
= Budding on the yeast
If a smaller cell is attached to a larger cell this indicates yeast as they have SEXUAL REPRODUCTION.
Bacteria DIVIDE into 2 EQUAL SIZE CELLS when they reproduce.
fungi (yeast) = anti-fungal Rx
bacteria = anti-biotic Rx
- What two factors limit bacteria such as E. coli multiplying every 20 minutes?
= Temperature
= Availability of nutrients
- Name the two main types of fungus
give an example of the clinical condition caused by each.
= yeast & mould
Yeast c’s
= Vaginal thrush caused by C. albicans
mould c’s
= Tinea (ringworm) which is invasion of the superficial (dermis) layers of the skin.
- Why are some viruses enveloped and others not?
How do enveloped viruses survive in the environment if the envelope is derived from cellular membrane?
Some viruses can derive an envelope from the way they leave a cell by
= BUDDING from the cell membrane TAKING A LAYER of the cell membrane with them, after the cell has produced new virus.
eg. budding virus
= HIV that BUDS from
helper T cells.
Other new viruses simply
= BURST the cell to escape.
eg. bursting virus
= POLIO
enveloped viruses survive in enviro by using either
= BLOOD (HIV) or
= MUCOUS (Influenza A)
to PROTECT them from the environment.
- How wide is the average bacterium?
How many rod bacteria could fit side by side across one leukocyte?
average bacterium width
= 0.2–2.0 µm (micro meters) in diameter.
Leukocytes are approximately
= 12 - 15 µm (micro meters) in diameter.
A rod bacteria
= 0.25 - 1.0 µm (micro meters) in diameter
= Thus, there could be 12 - 60 rod bacteria that could fit side by side across one leukocyte.
- Give one example of where bacteria use plasmids to our disadvantage and one example where we use plasmids to our advantage.
bact use Plasmids to our disadvantage
= Bacteria can use a plasmid as a VEHICLE TO GENETICALLY TRANSFER INFORMATION from one bacteria to another, ENHANCING THE RECIPIENT.
eg.
= TRANSFER ANTIBIOTIC RESISTANCE.
we use Plasmids as advantage
= Scientists can create a genetically modified organism by PUTTING A GENE ON A PLASMID and ATTACHING THEM TO ANOTHER ORGANISM to modify it.
eg.
= CREATING INSULIN
by putting PLASMID WITH THE INSULIN GENE into yeast, thus creating a GENETICALLY MODIFIED YEAST that can be GROWN TO CREATE INSULIN.
- What two ways could a cell wall help bacteria?
= 1. structural support.
= 2. protection
It can help protect the bacteria in low or high salt environments.
danilla note*
cell walls & antibiotics
= the cell wall is weakened by antibiotics so they then burst
- Why do bacteria make plaque?
==> Bacteria in the mouth causes a BIOFILM on the teeth.
==> Biofilm creates a framework of THIN CHANNELS for NUTRIENTS TO FLOW but RESTRICT PHAGOCYTES which would normally eat the bacteria.
==> This bacteria then CONTINUES TO BUILD which FORMS PLARQUE
==> excess bacterial growth
===» leading to GUM & TOOTH DISEASE or DECAY.
my version…
==> food w CARBS & STARCHES (sugars & starches) eg. milk, soft drink, raisins, cakes, candy
==> these LEFT ON TEETH
==> BACTERIA THRIVE ON CARBS & STARCH
==> BACTERIA PROD. ACIDS as result
==> acids DESTROY ENAMEL
===» the acids make there way BEYOND BARRIER, DESTROY TOOTH (tooth decay)
Why is it useful to know the Gram stain reaction of bacteria?
= important differential in IDENTIFYING a bacteria.
two groups of bacteria
= respond differently to antibiotics.
my question…
what does gram positive mean?
Gram-positive bacteria
= RETAIN the color of the CRYSTAL VIOLET stain in the Gram stain.
This is characteristic of bacteria that have a CELL WALL
composed of a
= THICK LAYER peptidologlycan
my question…
what does gram negative
mean?
Gram-negative bacteria
= LOSE the CRYSTAL VIOLET stain
= TAKE the color of the RED COUNTERSTAIN
in “Gram’s method” of staining.
This is characteristic of bacteria that have a CELL WALL
composed of
= a THIN LAYER peptidoglycan
What is meant by the cytopathic and cytocidal effects of viruses?
Cytopathic can be seen as
= STRUCTURAL CHANGES in a host cell
(caused by viral invasion)
Cytocidal refers to the
= cell actually being KILLED & SHRIVELLING
These two terms are used by laboratories to
= DESCRIBE what cell CHANGES they see
as you can’t actually see viruses with a light microscope.
Why does it matter whether an organism is either a virus, bacteria, fungus or protozoa?
identifying the type of organism, we can then
= identify the most APPROPRIATE FORM OF TREATMENT
Understanding the structure of the cell will influence which drug will be most effective.
Eg. antibiotics
= treat most bacteria
no effect against
= viruses
= fungal infections
limited effect against
= protozoal infections.
Why does HIV have an envelope but polio virus does not?
Polio is a
= NAKED VIRUS which will RUPTURE THE CELL- the mode of cell escape explains nerve damage.
HIV has an
= ENVELOPE it acquires as the NUCLEOCAPSID BUDS through the membrane.
Because it is LIPOPHILIC, and the cell membrane is also, it takes part of the membrane with it TO ADD PROTECTIVE LAYER.
How many golden staph fit side by side in 1 mm? How many could fit side by side between on fingerprint ridge and the next?
= 1000 golden staph fit side by side in (1 mm)
= 30 golden staph could fit side by side between one (FINGERPRINT RIDGE) and the next.
