Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

PHARM 232 Midterm 1 > Intro to Bacteriology > Flashcards

Intro to Bacteriology Flashcards

1
Q

What are the components of the cell wall (out to in).. What is special about gram-neg bacteria

A
  1. Outer membrane (gram-neg only)
  2. Peptidoglycan
  3. Periplasm (gram-neg only)
  4. Plasma membrane
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are some functions of the cell wall?

A
  1. Protection against osmotic damage
  2. Helps in cell division
  3. Holds shape of bacterial cell
  4. Hold target site for antibiotics, lysozymes, bacteriophages
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Why are drugs that target the cell wall synthesis useful?

A

Cell wall is essential for bacteria’s integrity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the peptidoglycan layer composed of? (3)

A
  • alternating strands of N-acetylglucosamine + N-acetylmuramic acid
  • a set of tetrapeptide side chains attached to the muramic acid
  • a set of identical peptide cross bridges
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What consists of the gram positive cell wall? (2)

A
  • lipoteichoic acid
  • wall techoic acid

(major surface antigens)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Which type of bacteria has higher antibiotic resistance (gram neg/positive)? Why?

A

Gram negative
- has an outer membrane (only in gram-neg)
- large antibiotic molecules penetrate the outer membrane slowly

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What does the outer membrane of gram-neg contain? (2)

A

Lipopolysaccharide
- LPS will still cause immunoresponse even after bacteria is dead –> must filter out LPS

Porins
- permit passive diffusion flow of low weight, hydrophilic compounds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is bacteria with defective cell wall called in gram neg/pos

A

Gram-neg: Spheroplasts
Gram-pos: Protoplasts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the gram staining procedure?
Explain which bacteria cells get affected and which don’t

A
  1. Apply crystal violet dye
  2. Apply iodine
    - binds crystal violet –> forms large complexes –> trapped in cell
  3. Alcohol wash
    - gram positive will hold crystal violet due to thick peptidoglycan layer
    - gram negative will wash away crystal violet due to thin peptidoglycan layer
  4. Apply Safranin
    - will stain gram-NEG only
    - gram-pos have no space for stain
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Define L-forms
Differentiate between unstable and stable L-forms

A

L-forms:
- when cell wall is removed but the bacteria can still grow and divide

Unstable: will revert back to having a cell wall when stimulus (penicillin) removed

Stable: Will not revert back to normal form

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are some functions of the cytoplasmic membrane

A
  1. Permeability and transport
  2. Biosynthetic functions
  3. Electron transport & oxidative phosphorylation
  4. Chemotactic systems
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are the 2 distinct areas in the cytoplasm called? What is it composed onf?

A
  1. Amorphous matrix:
    - contains ribosomes, nutrient granules, plasmids
  2. Inner nucleoid region
    - composed of DNA
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What do nucleoids in the cytoplasm used for?

A

Used for prokaryotes to package DNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Which part of the cytoplasm add bacteria properties such as toxigenicity and drug resistance

A

Plasmid
- replicate independently

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are functions of Glycocalyx (capsule/slime layer) (3)

A
  1. ADHERENCE of bacteria to human tissues (needed for causing infection)
  2. Enhances bacterial virulence
  3. Helps form biofilm
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What do the different arrangements of flagella mean?
Peritrichous
Monotrichous
Lophotrichous
Amphitrichous

A

Peritrichous: numerous flagella all over bacteria

Monotrichous: single polar flagella

Lophotrichous: collection of flagella at one end

Amphitrichous: flagella at both poles of the cell

17
Q

Explain role of pili and fimbriae? Which bacteria is it mainly found in?

A

Fimbriae (short appendages)
- adherence
- biofilm formation

Pili
- Adherence
- twitching and gliding motility
- Conjugation “sex” pili (transfer of DNA from one cell to another)

Mainly in gram-NEGATIVE bacteria

18
Q

Endospores (resistant/non resistant) to what? why? Which bacteria is it found in?

A

ONLY in gram-POSITIVE

Endospores are highly resistant to boiling, heating, disinfectants
- due to low water content, low metabolic activity, high conc. of calcium

19
Q

Explain the process of germination in endospores? What are the 3 stages?

A

Endopsore transformation into a vegetative (parent) cell under suitable conditions

3 stages: activation, initiation, and outgrowth

20
Q

When are pilli formed?

A

Formed in advance of an unfavourable environment.
- Endospore is very resistant: the parent bacteria could die in bad environment, but endospore will survive
- After good environment is restored, endospore can come out of dormancy and form new parent cell

21
Q

Differentiate between autotrophs and heterotrophs

A

Autotrophs:
- synthesize their own essential metabolites from CO2 and Nitrogen
- Ex. Cyanobacteria

Heterotroph
- requires preformed organic compounds
- Cannot synthesize their own metabolites

22
Q

What are the oxygen requirements for the following terms? Give example of each
Obligate aerobes
Obligate anaerobes
Facultative anaerobes
Aerotolerant anaerobes
Microaerophiles

A

Obligate aerobes
- aerobic respiration
eg. Pseudomonas aeruginosa (gram-neg)
Bacillus (gram-positive)

Obligate anaerobes
- growth inhibited by oxygen (can’t use it)
eg. Clostridium

Facultative anaerobes
- Able to live with/without oxygen
eg. E coli (gram-neg)
Staphylococci (gram-pos)

Aerotolerant anaerobes
- do not use oxygen, have enzymes that detoxify oxygen’s poisonous forms
eg. Streptocossus mutans

Microaerophiles
- require oxygen @2-10%, limited ability to detoxify hydrogen peroxide/superoxide
eg. Helicobacter pylori

23
Q

What do low temperatures effect on bacterial membrane?

A

Becomes rigid and fragile

24
Q

What are the preferred pH for the following:
Neutrophils
Acidophiles
Alkaliphiles

A

Neutrophils: pH 6-8
Acidophiles: pH <4
Alkaliphiles: up to pH 11.5

25
Q

What effect do endospores have when there is low water in the cell?

A

Cease most metabolic activity

26
Q

Define generation time

A

Time required for a bacterial cell to divide
- most common is 1-3 hours

27
Q

How is a typical growth curve obtained?

A

In an enclosed vessel/batch culture

28
Q

Explain the 4 DISTINCT phases of a growth curve

A
  1. Lag phase
    - time period between inoculation and beginning of growth (does not grow right away)
  2. The log phase
    - cell begin to divide according to a logarithmic increase
    - MOST SUSCEPTIBLE TO ANTIMICROBIAL DRUGS HERE
  3. Stationary phase
    - Due to nutrient/toxic depletion
    - growth slows until # of cells produced = # of cells that die
  4. Death phase
    - Decline in # of viable bacteria
29
Q

What are the 2 critical determinants of getting a disease in an organism’s perspective? how about in a host’s persceptive?

A

Organism’s perspective
1. # of organisms
2. Virulence of those organisms

Host’s perspective
1. Innate immunity
2. Acquired immunity

30
Q

What are the 5 stages of bacterial infections

A
  1. Exposure to pathogen
  2. Adherence to skin/mucosa
  3. Invasion through epithelium
  4. Colonization AND growth.. causes:
    a. toxicity
    b. Invasiveness
  5. Tissue damage/disease
31
Q

What are the 5 determinants of bacterial pathogenesis

A
  1. Transmission
  2. Adherence to cell surface
  3. Invasion + intraceullar survival
  4. Toxic Production
  5. Intraceullar pathogenecity
32
Q

Explain the 4 major adherence factors?
Capsule/slime layer
Adherence proteins
Lipoteichoic acid
Fimbriae (pili)

A
  1. Capsule/slime layer
    - capsule promotes adherence to the brush border of intestinal villi
  2. Adherence proteins
    - Opa protein on the cell binds to receptors on epithelium
  3. Lipoteichoic acid
    - faciliates binding to respiratory mucosol receptor (along with M protein)
  4. Fimbrae
    - pili faciliates binding to epithelium
33
Q

Explain the enzymes secreted by invasive bacteria
Hyaluronidase
Coagulase
Hemolysins/leukocidins
Immunoglobulin protease

A

Hyaluronidase
- Splits hyaluronic acid –> improves spreading factor

Coagulase
- coagulates plasma –> forms fibrin wall around organisms

Hemolysins/leukocidins
- Destroy RBCs
- Destroy leukocytes and macrophages

Immunoglobulin protease
- Degrades IgA –> allows organism to adhere to mucous membrane

34
Q

Differentiate between exotoxins and endotoxins

Which type of bacteria is common in each?

A

Exotoxins
- proteins produced inside pathogenic bacteria.. then released
- common in gram-POS

Endotoxins
- toxins composed of lipids that are part of the cell wall.. released when cell dies
- common in gram-NEG

PHARM 232 Midterm 1 (6 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions