Flashcards in Lecture #1 - Bacterial Cytology Pt.1 Deck (58):
what do coccus bacteria look like , give ex
round ball, staphylococcus, streptococcus
describe shape of coccobacillus
stubby rod, E coli
what does a vibrio look like
comma, vibrio cholera
what does a bacillus look like
are all bacteria the same size
no, they come in various sizes, some as small as 0.4 nanometers
a group of related genera is known as a
a group of related species is known as a
a group of related strains is known as a
a set of strains within in a species is known as a ____ aka a _____
a variant of the same species is known as a
What is the name of the serotype of e. coli that causes disease?
t/f a serotype has huge differences between in structure between itself and the variant
false, there can be a tiny structural difference, for example only a difference in 1 sugar, but this has a huge impact
in gram staining the primary stain is known as
ethyl alcohol in gram staining is used to
decolorize. It will remove the primary stain from gram negative bacteria. It is not strong enough to remove the stain from gram positive bacteria.
what is the purpose of iodine in gram staining
it is used to "fix" the primary stain in the cell wall
briefly list the 5 steps to gram stain procedure
1. Have cells on slide
2. stain w/ crystal violet
3. use iodine (mordant) to fix primary stain in cell wall
4. decolorize stain with alcohol
5. counter stain with safranin
gram staining helps differentiate between gram ____and gram ___ bacteria
gram negative and gram positive
The first step that gram negative and gram positive bacteria look different is during __
decolorization. The alcohol will remove the primary stain (crystal violet) from gram negative, but not gram positive.
During a gram staining procedure, cells are washed with alcohol and turn clear/white. They must be...
at the end of a gram staining procedure cells are purple. They must be
at the end of a gram stain procedure cells are red. They must be
differences in the ___ of the cell wall help to explain why gram staining works
what happens to the pores in peptodiglycan when it is washed with alcohol
the pores tighten. Since gram positive have a thick cell wall with lots of pores, the stain stays in it. The gram negative have hardly any peptodiglycan so the stain is easily washed away with the alcohol .
T/F both gram negative and gram positive bacteria have peptodiglycan
true, gram positive just has a much thicker layer than gram negative.
if you forget to add the mordant while doing gram staining. What color will gram positive stain
red , because iodine (the mordant) helps to fix the primary stain to the cell wall, without it the primary stain wouldn't stain.
A gram staining procedure is done and the cells are purple. Are they gram positive or gram negative?
A gram staining procedure is done and the cells are red. Are they gram positive or gram negative
List two differences between gram positive and gram negative bacteria in terms of their cell wall
1. Gram Positive have teichoic acids , gram negative do not
2. Gram negative have an outer membrane, their is NO outer membrane in gram positive.
When looking at a cell envelope we see that it has teichoic acid in the membrane. Is it gram negative or gram positive
Only gram positive have teichoic acid
when looking at a cell envelope we see that there is an outer membrane. Is it gram negative or gram positive?
Gram negative. Gram positive do NOT have OUTER membranes
T/F all bacteria have capsules
false. Some do and its a very important virulence factor
in gram negative bacteria the space between the outer membrane and cytoplasmic membrane is known as
periplasmic space. There are lots of degraded enzymes found here.
In which region of a gram negative bacteria is peptodiglycan found in
There is a very thin layer suspended in the periplasmic space.
T/f bacterial cells have a singular chromosome that is covalently closed and negatively super coiled.
What allows for the chromosome of a cell to be compacted tightly in the cell
Negative super coiling allows for this
What are the two main components of the cytoplasmic membrane
70% protein, 30% lipid.
What is one major difference in the cytoplasmic membrane between eukaryotic and bacteria cells
The cytoplasmic membrane in bacteria DO NOT have sterols ( like cholesterol) . Unlike in eukaryotes which do have sterols.
What is the only bacteria that does have sterol
What is unique about mycoplasmas cell wall
They DONT have a cell wall!
What would happen if someone tried to treat mycoplasma with penicillin
It wouldn't have any affect because mycoplasma are unique in that there is no cell wall. Since there is no cell wall there is not target for the drug to attach!
T/F The only role of the cytoplasmic membrane is to transport things in and out of cell
False! It does a lot more than just that. It has a role in oxidative phosphorylation, electron transport
T/F periplasmic space is only found in gram negative bacteria
True! It is the space between the outer membrane and the cytoplasmic membrane.
what is the function of the cell wall
gives shape and structure to bacterial cells
what is the function of the capsule
1. allow them to avoid phagocytosis
2. allow them to stick to things (like medical eqp)
What are capsules typically made of
poly saccharide polymers (sugars)
what is unique about the capsule of bacillus anthrasis?
the capsule is made up of amino acids instead of sugars. It is made of poly d glutamic acid.
What is the role of glycocalyx?
loosely attached to the cell and Allows bacteria to attach to surfaces . it can coat medical equip and cause an infection
describe the difference between glycocalyx and the capsule
glycocalyx is loosely bound and capsule tightly bound
what does the term antigenic mean
Antigenic = an antigen that triggers the immune system to make anti body.
Capsules have K antigens T/F
T/F you can easily see the capsule of a bacteria under a microscope
You cant see capsule unless you do a capsule stain or you can make the capsule swell.
T/F capsules block phagocytosis
What is the role of F pilli
conjugation process, mechanism of gene exchange , mating bridge
_______ refers to the mechanism by which a bacteria alters its surface proteins in order to evade a host immune response.
antigenic variation. Slight changes in proteins can outsmart antibiotics
_____ are involved in movement and locomotion
What is chemotaxis
response to stimuli in the environment
What is the role of cytoplasmic inclusions
storage mechanisms when nutrients low in cell.