PART 1- Hussein Exam 1

based ONLY off STUDY GUIDE!!!!!!!!!!

What’s the difference between pasteurization and sterilization?

• pasteurization- kill common pathogens

• sterilization- kill ALL living microorganisms, spores, and viruses

Match the organism to its infectious disease:

Organism	Infectious Disease
Animal (parasite)
Bacterial
Fungal
Protozoal
Viral

Disease options: HIV-AIDs, Influenza, Athlete’s foot, malaria, tuberculosis, wuhan coronavirus, schistosomiasis (trematode), syphilis

Organism	Infectious Disease
Animal (parasite)	Schistosomiasis (trematode)
Bacterial	Tuberculosis Syphilis
Fungal	Athlete’s foot
Protozoal	Malaria (parasite)
Viral	HIV-AIDs Influenza Wuhan Coronavirus

What are Koch’s 4 postulates?

1. The cultured organism should cause disease when introduced into a healthy animal

2. The organism must be found in all animals suffering from the disease, but not in healthy animals

3. The organism must be isolated from a diseased animal and grown in pure culture

4. The organism must be re-isolated from the experimentally infected animal

Yeast/Fungi have what kind of cell walls? Do they have organelles? What size are their ribosomes?

• CHITIN CELL WALLS

• yes organelles, like mitochondria

• 80S ribosomes

Answer the following about Prokaryotes and Eukaryotes:

	Prokaryotes	Eukaryotes
Members
Nucleus?
Haploid or Diploid?
Ribosome size
Organelles?

	Prokaryotes	Eukaryotes
Members	bacteria	Protista fungi plants animals
Nucleus?	NO	YES
Haploid or Diploid?	Haploid	Diploid
Ribosome size	70S (30S,50S)	80S (40S,60S)
Organelles?	NONE	Yes—> ER, golgi, mito

Do prokaryotes or eukaryotes have linear DNA, specialization, compartmentalization, mitosis/meiosis, and tissue/organ systems?

eukaryotes

Fill in the following table comparing G+ and G- bacteria:

	Gram +	Gram -
Cell Wall/ Peptidoglycan thickness
Outer membrane?
Gram Stain Color
Endotoxins/LPS?

	Gram +	Gram -
Cell Wall/ Peptidoglycan thickness	Thick	Thin
Outer membrane?	Absent	Present
Gram Stain Color	Purple	Pink/Red
Endotoxins/LPS?	Absent	Present

What are the steps of a Gram stain and how do you interpret the results?

1. Stain with purple (“crystal violet”)

2. Modify with KI (potassium iodide)

3. decolorize with alcohol

4. counterstain with red (“safranin”)

5. RESULTS

   • GRAM + REMAIN PURPLE

   • GRAM - BECOME PINK

What are the steps of an acid-fast stain and how do you interpret the results?

1. stain with red (“carbol-fuchsin”)

2. decolorize with acid alcohol

3. counterstain with methylene blue

4. RESULTS

   • Acid-fast REMAIN RED

   • Others become BLUE

Which of the following has cell walls made of peptidoglycan?

a. plants

b. animals

c. bacteria

d. fungi

c

What are the monomers for peptidoglycan cell walls?

NAG-NAM Pentapeptide monomers

NAG-NAM Pentapeptide monomers are what type of monomer?

amino sugars

What is the function of a peptidoglycan cell wall in bacteria?

PREVENT osmotic lysis

What’s the difference between Gram + and Gram - bacteria in terms of the tetrapeptides that link together the peptidoglycan?

• Gram +

  • peptide bridge cross links Lys to D-Ala

  • tetrapeptide would be: L-Ala-D-Gln-L-Lys-D-Ala

• Gram -

  • DAP cross-links directly to D-Ala

  • tetrapeptide would be: L-Ala-D-Glu-meso-DAP-D-Ala

What is the function of bactoprenol?

carrier molecule/transporter for peptidoglycan monomers made in the cytosol

What are the 4 shapes of bacteria?

1. cocci (round)

2. rods

3. spiral

4. vibrio (comma)

Pentaglycine is found in Gram ____________ cell walls.

a. negative

b. positive

b

What is the best kind of antibacterial drug?

• what ribosomes does it inhibit?

• what else does it inhibit?

best kind of abx—>

• inhibits 30S, 50S, or 70S ribosomes (aka the ones in bacteria)

• a drug that INHIBITs peptidoglycan synthesis

Does this describe gram - or gram + bacteria?

• bacteria with 2 phospholipid bilayers, thin peptidoglycan wall, and has LPS

gram -

Does this describe gram - or gram + bacteria?

• bacteria with thick peptidoglycan wall and teichoic and lipoteichoic acids

gram +

Where are teichoic acid and lipoteichoic acid found? function?

(not in the sg, i added in case)

• Teichoic acid—> extends through cell wall—> trigger innate immune response, activate complement

•  Lipoteichoic acid—> attached to lipids of the cell membrane—> adhesion/penetration of host cells, resistance to phagocytosis

What are Polymyxins antibiotics used for? Why?

for topical infections with GRAM - BACTERIA—> bc polymyxins disrupt bacterial membranes and the outer membrane on Gram - bacteria is easily accessible

What are the 4 phases of the bacterial growth curve?

1. lag phase (“getting comfy”, making new enzymes, no bacteria growth yet)

2. log phase (exponential growth, most sensitive to drugs/radiation here)

3. stationary phase (death rate= division/growth rate)

4. death phase (death>division)

Beta-lactam antibiotics like penicillin work by inhibiting what enzyme? What phase of the bacterial growth curve are they most effective?

inhibit transpeptidase, most effective during EXPONENTIAL growth phase of bacteria

What type of bacteria completely lack the enzymes catalase and hydrogen peroxide dismutase?

a. facultative anaerobes

b. obligate anaerobes

c. microaerophiles

d. obligate aerobes

e. aerotolerant anaerobes

b. obligate anaerobes

What type of bacteria can live with or without O2?

a. facultative anaerobes

b. obligate anaerobes

c. microaerophiles

d. obligate aerobes

e. aerotolerant anaerobes

a. facultative anaerobes

What are capnophiles?

Thrive in high CO2 concentrations, and either require/tolerate oxygen

Bacteria can be classified based on their optimal temperature. What are the 4 types of bacteria and their optimal temperatures?

1. mesophile (35° and 38°C)- most common

2. psychrophile (cold 4°C)

3. thermophile (hot above 50°C)

4. hyperthermophile (hot springs above 80°C)

For EACH of the following processes, what is the final/terminal electron acceptor?

1. aerobic respiration

2. anaerobic respiration

3. glycolysis

4. fermentation

1. aerobic respiration- O2

2. anaerobic respiration- inorganic molecule

   • Sulfate reducers take (SO4^-2) —> H2S

   • Nitrate reducers take (NO3^-) —> NO2^- —> NO—> N2

3. glycolysis- NAD+—> NADH

4. fermentation- organic molecule

What is the end product of glycolysis under AEROBIC conditions? How much is made by one glucose molecule?

pyruvate is the end product, 1 Glucose= 2 pyruvate

Substrate level phosphorylation is a type of ATP production that involves direct phosphate transfers and generates how much ATP in glycolysis and the TCA?

2 in glycolysis, 2 in TCA, 4 total

What is the total NADH molecules produced from the metabolism of one glucose molecule?

10

What is the molecule produced from glucose that enters the TCA?

acetate from acetyl-CoA

Which of the following is NOT an end product of fermentation?

a. acetic acid

b. lactate

c. ethanol/ ethyl alcohol

d. citrate

d

Fermentation uses substrate level phosphorylation to generate ___ ATP.

a. 1

b. 2

c. 3

d. 4

b

What is fermentation? What is it important in?

• fermentation is the anaerobic breakdown of carbs

• important in vigorous exercising muscle, milk fermenting bacteria

What is the net ATP yield of aerobic respiration? What is the net ATP yield of anaerobic respiration?

(not in the sg, but I thought add)

aerobic—>38 ATP

anaerobic—> ≤ 36 ATP

Fastidious bacteria need what?

many supplements needed in their growth medium (can’t just have a simple medium, ex in picture)

What are the 4 genetic transfer mechanisms?

1. transformation

2. conjugation

3. R-plasmids

4. transduction

Answer the following about Transformation:

• What type of DNA is up taken by the bacteria? Describe it.

• It is susceptible to what? why?

• What experiment discovered bacterial transformation?

• Competence to take up the DNA can be natural or _________.

• naked DNA- DNA released from dead/lysed cells into environment

• susceptible to NUCLEASES—> bc naked DNA is fragile/easily degraded by nucleases

• GRIFFITH’s EXPERIMENT- discovered bacterial transformation

• competence can be natural or artificial

What does natural and artificial competence refer to regarding transformation?

• natural- ability of bacteria to take up DNA

• artificial- permeability results from heat/cold shock

  • (wouldn’t normally take up DNA)

If I chill a bacteria with cations like CaCl2, that would be __________ competence.

a. natural

b. artificial

b

Conjugation is direct cell-to-cell transfer of DNA through a___________________.

F-pilus/ conjugation bridge

What is a small circular piece of DNA that carries genes for conjugation?

Fertility plasmid/ F plasmid

An F+ bacteria conjugates with a F- bacteria. What is the result?

sex change—> F- bacteria turns F+

What are Hfr cells in terms of conjugation?

they have an INTEGRATED F factor into its chromosome (instead of having it as a separate plasmid like in F+)

With which of the following has a transfer of chromosomal genes?

SATA:

a. F+

b. F-

c. Hfr

d. F’

c,d —> both involve transfer of chromosomal genes

(Hfr transfers more than F’)

An F’ bacteria conjugates with a F- bacteria. What is the result?

sex change—> F- bacteria turns F’

What are R plasmids? What bacteria is an example of a bacteria with R-plasmids?

• R-plasmids (resistance plasmids) are extrachromosomal DNA molecules that carry antibiotic resistance genes

• ex: Salmonella

λgt11 uses ____________ transduction to introduce genes into bacteria.

a. generalized

b. specialized

b

Answer the following about transduction:

• what organism does it use to transfer genes?

• What is made when a bacteriophage integrates into the bacterial DNA? What is that process called?

• What is the role of suppressor proteins?

• uses BACTERIOPHAGES

• PROPHAGES are made during LYSOGENY (when the bacteriophage is integrated into the bacteria DNA)

• role—> how the bacteriophage stays integrated into bacteria DNA

What are the 2 types of transduction?

• generalized transduction (ad random integration of phage and donor genes in the chromosome; lytic cycle)

• specialized transduction (integrate in certain site on the recipient chromosome: lytic or lysogeny)

Virulence factors are molecules or structures that help bacteria evade the immune system. What are two examples of virulence factors? Which is commonly used by meningitis bacteria?

• IgA protease

• Capsule (used by meningitis bacteria)