General BacT and Mycology - Muller

Question 1

The phylogenetic tree of life contains 3 domains. Which are prokaryotes? Which are eukaryotes?

Answer 1

Prokaryotes: BacT + Archaea

Eukaryotes: Eukaryota (fungi, plants, animals, etc)

Question 2

Where is genetic info contained in a prokaryotic cell?

Answer 2

In a single haploid circular chromosome

Question 3

Regarding bacteria, why can nutrients easily and quickly reach all parts of the cell?

Answer 3

Bc bacT are small but have a large surface area to volume ratio

Question 4

True or False: Not all bacteria have a capsule

Answer 4

TRUE

Question 5

A bacterial capsule has a _________ outer layer

Answer 5

polysaccharide!!

Question 6

A bacterial cell wall is made of a _____________ layer

Answer 6

Peptidoglycan layer

Question 7

Does Gram + or Gram - have a thicker peptidoglycan layer?

Answer 7

Gram + has a thicker peptidoglycan (cell wall) layer

Question 8

What is the purpose of gram staining?

Answer 8

Differentiates bacT by properties of their cell walls and by detecting peptidoglycan

Question 9

What is the purpose of acid fast staining?

Answer 9

stains acid fast positive organisms due to mycolic acid in present in cell wall

Question 10

What is an example of a bacteria you would use acid fast staining for?

Answer 10

Mycobacteria - mycolic acid in cell wall

Question 11

What is the antigenic component of gram + bacteria?

Answer 11

Lipotechoic acid

Question 12

Which is the antigenic component in Gram neg bacteria?

Answer 12

Lipopolysaccharides (LPS) (part of cell wall)

Specifically Lipid A - endotoxin

Question 13

Does gram + or gram - contain the Lipid A?

Answer 13

Gram neg!

Question 14

What is Lipid A?

Answer 14

Endotoxin in cell wall (LPS) of gram neg bacteria

activates immune system and exerts harmful effects

Question 15

What is the virulence factor for mycobacteria?

Answer 15

Mycolic acid

Question 16

What is endoflagella?

Answer 16

Flagella in the periplasmic space - only in Gram neg bacT!!!

Corkscrew like motility

Ex: Spirochetes have endoflagella

Question 17

Explain the different types of pili/ fimbriae

Answer 17

Attachment pili: adherence to host

Conjugation pili: transfers genetic info

** pili also contributes to antigenicity (Ex: diarrhea in neonatal piglets)

Question 18

Endospores are produced by which bacteria when exposed to nutrient depletion?

Answer 18

Clostridium + Bacillus

Question 19

What are characteristics of endospores?

Answer 19

1. Cryptobiotic state of dormancy
2. Most durable cell in nature
3. Survives a long time under extreme conditions
4. Formed intracellularly

Question 20

Which bacteria are exceptions to general bacterial properties and why?

Answer 20

1. Mycoplasma: no cell wall
2. Leptospira: 2 circular chromosomes
3. Borrelia burgdorferi: linear chromosomes

Question 21

Define the lag phase

Answer 21

increase in cell size, active metabolism of cells but NO DIVISION

Question 22

Define exponential or logarithmic phase

Answer 22

cells multiply at max. rate

Question 23

Define the maximal stationary phase

Answer 23

exhaustion of nutrients/ accumulation of toxins

balance between slow multiplication and cells dying

Question 24

What nutrients are required for bacteria to grow?

Answer 24

Carbon and nitrogen

Question 25

What is the bacterial sources of metabolic energy?

Answer 25

Fermentation Respiration Photosynthesis

Question 26

What is a microaerophile?

Answer 26

Bacteria that requires a small amount of O2 to grow

Question 27

_________ are bacteria that grow in 70-110 °C

Answer 27

Hyperthermophiles

Question 28

Define exotoxins

Answer 28

proteinaceous toxins made by bacteria that exerts action on specific target cells when secreted or released following lysis *** produced inside gram positive bacteria

Question 29

Define endotoxins

Answer 29

cell wall components (LPS) that induce inflammation by stimulating immune system ** part of cell wall of gram neg bacteria

Question 30

What are examples of biofilm?

Answer 30

Dental plaque biofilm in catheters UTI

Question 31

Bacteria produce _________which allows cells to communicate

Answer 31

Autoinducers / pheromones

Question 32

Explain quorum sensing

Answer 32

When bacterial population is HIGH autoinducers bind to receptors and promote group behavior (Ex: biofilm formation, virulence, conjugation, etc.) When bacterial population is LOW autoinducers diffuse away from bacteria / no group behavior

Question 33

______ + ________ help mediate transfer of genetic material

Answer 33

Capsules , fibriae/pili

Question 34

All bacT contain peptidoglycan except ___________

Answer 34

Mycoplasma

Question 35

________ is a harmful endotoxin in Gram negative bacT

Answer 35

Lipid A

Question 36

What sequences of events are required to act as a pathogen?

Answer 36

1. Must find appropriate host 2. Must evade host 3. Compete w normal microbiota to adhere to host tissues 4. Multiply inside host 5. Causes damage to host

Question 37

True or False: Most bacteria are intracellular

Answer 37

FALSE MOST ARE EXTRACELLULAR

Question 38

Give examples of obligate intracellular pathogens

Answer 38

1. Rickettsia 2. Chlamydia

Question 39

Give examples of facultative intracellular pathogens

Answer 39

1. Mycobacterium 2. Rhodococcus 3. Bartonella

Question 40

Extrachromosomal DNA in bacteria is known as ________

Answer 40

Plasmids

Question 41

How can bacteria transfer genetic material and virulence factors?

Answer 41

1. Transformation (in the lab) 2. Transduction (via bacteriophages) 3. Conjugation (via plasmid)

Question 42

What is pathogenesis?

Answer 42

mechanism that leads to a disease

Question 43

What is pathogenicity?

Answer 43

ability of a microorganism to damage a host

Question 44

What is virulence?

Answer 44

relative capacity of a pathogen to damage a host