Lecture Exam #3 Review

Question 1

1) What group of antibiotics is always bacteriostatic?
2) What group of antibiotics is usually bacteriostatic?

Answer 1

1) Tetracyclines
2) Macrolides

Question 2

What 4 groups of antibiotics are bacteriocidal?

Answer 2

1) B-lactam
2) Aminoglycosides
3) Quinolones
4) Rifampin & Rifabutin

Question 3

1) Name the 3 cell wall synthesis inhibitor antibiotic classes
2) Name the 3 protein synthesis inhibitor antibiotic classes

Answer 3

1) B-lactam antibiotics, glycopeptides, polypeptides
2) Aminoglycosides, tetracyclines, and macrolides

Question 4

1) Name the 2 nucleic acid synthesis inhibitor antibiotic groups
2) Name the 2 antimetabolite antibiotic groups

Answer 4

1) Quinolones and Rifampin/ Rifabutin
2) Sulfonamides and trimethoprim

Question 5

What 3 types of antibiotics are always effective against G+ bacteria?

Answer 5

1) Glycopeptides
2) Bacitracin (type of polypeptide)
3) Rifampin/ Rifabutin

Question 6

What 2 types of antibiotics are effective against G- bacteria?

Answer 6

1) Polymyxins (type of polypeptide)
2) Aminoglycosides

Question 7

Which group(s) of antibiotics bind to the 50S ribosome? Give examples of each group.

Answer 7

Macrolides: Erythromycin, azithromycin, and clarithromycin

Question 8

Which group(s) of antibiotics bind to the 30S ribosome? Give examples of each group.

Answer 8

1) Aminoglycosides: gentamicin and tobramycin
2) Tetracyclines

Question 9

1) What do quinolones specifically prevent?
2) What does rifampin/ rifabutin specifically prevent?

Answer 9

1) Quinolones: inhibit DNA replication
2) Rifampin/ rifabutin: inhibit RNA polymerase

Question 10

1) What is the specific action of bacitracin?
2) What is the specific action of polymyxin?

Answer 10

1) Bacitracin: prevents recycling
2) Polymyxin: inserts into cell membrane

Question 11

1) What is the specific action of B-lactam antibiotics?
2) What is the specific action of glycopeptides?

Answer 11

1) B-lactam: Binds to PBPs to prevent transpeptidation during peptidoglycan synthesis.
2) Glycopeptides: Binds to D-Ala-D-Ala to prevent cross-linking during peptidoglycan synthesis

Question 12

1) What is the specific action of sulfonamides?
2) What is the specific action of trimethoprim?

Answer 12

They both inhibit enzymes in the bacterial pathway for the production of tetrahydrofolic acid, which is needed to make nucleic acids and formyl-methionine

Question 13

What are the 4 main types of control of microorganisms?

Answer 13

1) Physical
2) Chemical
3) Mechanical
4) Biological

Question 14

What are the types of physical control?

Answer 14

1) Heat (wet or dry heat)
2) Radiation (UV or ionizing)
3) Filtration
4) Low temperature
5) High pressure
6) Desiccation
7) Osmotic pressure (hypertonic)

Question 15

1) How does dry heat kill microbes?
2) How does high pressure kill microbes?
3) How does osmotic pressure kill microbes?

Answer 15

1) Dry heat: Oxidation of cell parts and denaturing proteins
2) High pressure: Bursts cells
3) Osmotic pressure: Hypertonicity causes water to leave cells

Question 16

Name and describe 4 types of filtration

Answer 16

1) Depth filters: Filter liquid through diatomaceous earth or porcelain
2) Membrane filters: Filter liquid through a porous membrane
3) HEPA filters: Fiberglass depth filters; sterilize air in biosafety cabinets
4) New micron graphene filters: Use graphene sheets and electricity to sterilize air

Question 17

Name 7 types of chemical control and what each does to a cell

Answer 17

1) Aldehydes: inactivate proteins and nucleic acids
2) Hydrogen peroxides: inactivate proteins
3) Heavy metals: inactivate proteins
4) Halogens: inactivate proteins
5) Alcohols: denature proteins
6) Quaternary ammonium compounds: disrupt cell membranes
7) Phenols: denature proteins and disrupt membranes

Question 18

Name the 5 types of bacteria involved in the sulfur cycle and what type of reaction each is involved in

Answer 18

1) Alteromonas: dissimilatory
2) Desulfovibrio: dissimilatory
3) Thiobacillus: assimilatory
4) Thiothrix: assimilatory
5) Thiomargarita: assimilatory

Question 19

Name the 7 bacteria involved in the nitrogen cycle and what type of reaction they are involved in

Answer 19

1) Fixation: Azotobacter and Rhizobia
2) Nitrification: Nitrosomonas and Nitrobacter
3) Denitrification: Pseudomonas and Paracoccus denitrificans and thiobacillus

Question 20

What is the difference between exogenous and endogenous infections?

Answer 20

1) Exogenous: Disease from external source
2) Endogenous: Disease from normal host microbial flora

Question 21

Define primary pathogens, opportunistic pathogens, and strict pathogens

Answer 21

1) Primary pathogens: Cause disease in a healthy host
2) Opportunistic pathogens: Cause disease in a host with a compromised immune system
3) Strict pathogens: Always associated with disease

Question 22

What are the 4 protections of the mouth/ oropharynx/ nasopharynx?

Answer 22

1) Hairs of nares act as a filter
2) Lysozymes in nasopharynx secretions
3) Lysozyme IgA in saliva
4) Desquamation (shedding)

Question 23

What are the 7 protections of the skin?

Answer 23

1) Desquamation (shedding)
2) Dryness
3) Salt content
4) Toxic fatty acid presence
5) Acidic pH (5.5)
6) Lack of nutrients
7) Normal flora

Question 24

What are the 4 protections of the GI tract?

Answer 24

1) Mucus barrier
2) Secretory IgA antibodies
3) Bile
4) Antibacterial pancreatic enzymes

Question 25

What are the 4 protections conferred by GI flora?

Answer 25

1) Bacteriocin production
2) Toxic short chain fatty acid production
3) Compete for attachment sites/ nutrients
4) Stimulate cross-reactive antibiotics

Question 26

1) What 3 things protect the bladder?
2) What protects the vagina?

Answer 26

1) Bladder: Flushing, urethra length, and hypertonicity of kidneys
2) Vagina: Low pH due to production of lactic acid from glycogen by lactobacilli

Question 27

What is the basic idea of the carbon cycle? What 2 things are involved?

Answer 27

As humans add CO to the environment, it is cycled through the land, air, and water through a series of fixations and respirations (largely by bacteria)

Question 28

What are the 4 basic ideas of the nitrogen cycle?

Answer 28

Nitrogen is cycled through the air and earth due to:
1) Ammonification: release of ammonia due to deamination
2) Nitrification: ammonium ion is oxidized to make nitrate
3) Denitrification: nitrate is used as an electron acceptor (when no oxygen)
4) Nitrogen fixation: nitrogen gas converted to ammonia

Question 29

What is the basic idea of the sulfur cycle? What 4 things are involved?

Answer 29

Sulfur is cycled through the air and land (as its produced through fossil fuel burning) due to assimilation, dissimilation, oxidation, and anaerobic respiration.

Question 30

What is the basic idea of the phosphorus cycle?

Answer 30

Phosphorus is cycled through the land and water sources as organic matter (rock weathering, fertilizer) enters the cycle once it is converted to elemental phosphorus. It forms insoluble complexes that go into water sources.

Question 31

Describe the incubation period, symptoms, and food sources of:
1) Salmonella
2) Norovirus
3) Campylobacter

Answer 31

1) Salmonella: 8-48 hours
-Symptoms: Gastroenteritis (diarrhea, fever, vomiting).
-Food source: Fruits, vegetables, poultry, eggs, cheese
2) Norovirus: 12-48 hours (‘cruise ship virus’)
-Symptoms: Diarrhea, fever, nausea
-Food source: Produce, shellfish, salad, sandwiches
3) Campylobacter: 2-5 days
-Symptoms: Diarrhea, fever, cramps
-Food source: Poultry, contaminated water

Question 32

Describe the incubation period, symptoms, and food sources of:
1) Toxoplasma
2) E. coli 0157
3) Listeria

Answer 32

1) Toxoplasma: 1-3 weeks
-Symptoms: Enlarged lymph nodes, headaches, myalgia.
-Food source: Raw meat, contaminated water (& cat litter box)
2) E. coli 0157: 1-10 days
-Symptoms: Severe diarrhea, vomiting, HUS
-Food source: Contaminated water, raw milk/ fruit/ veggies, hamburger meat
3) Listeria: 3-70 days
-Symptoms: Fever, stiff neck, confusion, myalgia
-Food source: Deli meats, hot dogs, raw milk and dairy, soft cheese (survives in fridge).

Question 33

What are the two types of food related disease? Describe them.

Answer 33

1) Food-borne infections: ingestion of pathogen-grown-invasion/ toxin production (food poisoning) (toxins made in body)
2) Food intoxications: results from microbial growth in food products (toxins made in food)

Question 34

1) List the general intrinsic factors of microbial growth in foods
2) List specific intrinsic factors of microbial growth in foods
3) List the general extrinsic factors of microbial growth in foods

Answer 34

1) General intrinsic: Composition, physical, and biological state
2) Specific intrinsic: Food composition, pH, physical structure, and availability of water
3) General extrinsic: Temperature, relative humidity, gasses, contaminating microorganisms

Question 35

What are the 4 places in which food can be contaminated?

Answer 35

1) Production: spraying fields with contaminated water, contamination before harvest
2) Processing: using contaminated water to wash
3) Distribution: being left in warm weather before distribution
4) Preparation: being contaminated by a human in the kitchen

Question 36

What are the 4 places in which food can be contaminated?

Answer 36

1) Production: contamination before harvest
2) Processing: using contaminated water to wash
3) Distribution: being left in warm weather before distribution
4) Preparation: being contaminated by a human in the kitchen

Question 37

What did Sir Alexander Fleming (1881-1955) do for industrial microbiology?

Answer 37

1) Discovered the enzyme lysozyme in 1922.
2) Discovered the antibiotic penicillin from the fungus Penicillium notatum in 1928.
3) Shared Nobel Prize in Physiology or Medicine in 1945 with Florey and Chain.

Question 38

What are the 5 general steps of fermentation?

Answer 38

1) Start with a stock culture in a bioreactor (O2 and pH control)
2) Recovery (filtration)
3) Recovery extraction (solvents)
4) Purification
5) Product.

Question 39

1) What are the primary metabolites of fermentation?
2) What are the secondary metabolites of fermentation?

Answer 39

1) Primary: amino acids, nucleotides, fermentation end products
2) Secondary: antibiotics

Question 40

Name 5 ways to increase the yields of microbial products and define each

Answer 40

1) Mutagenesis: inducing mutagenesis by stressing the bacteria out; doesn’t allow for targeting specific mutations
2) Protoplast fusion: 2 organisms fuse together, allows for recombination
3) Genetic transfer between organisms: horizontal gene transfer (transformation, conjugation, transduction)
4) Modification of gene expression: modify transcription binding sites, modification of proteins, etc.
5) Directed evolution: direct approach by mutating specific targets, allows for specific inactivation or complementation of a gene.

Question 41

Name 5 ways to increase the yields of microbial products and define each

Answer 41

1) Mutagenesis: inducing nonspecific mutagenesis by stressing the bacteria out
2) Protoplast fusion: 2 organisms fuse together, allows for recombination
3) Genetic transfer between organisms: horizontal gene transfer (transformation, conjugation, transduction)
4) Modification of gene expression: modification of transcription binding sites, proteins, etc.
5) Directed evolution: mutating specific targets, allows for specific inactivation or complementation of a gene.

Question 42

Describe the 3 levels of food-borne pathogen testing and when each happens

Answer 42

1st level: Testing to prevent (before it leaves farm)
2nd level: Testing to protect (prior to consumption)
3rd level: Testing to recover (determine origin of an outbreak)