Pathogenic Microbiology Test I

Front 1

How are prokaryotes different than eukaryotes?

Back 1

No nucleus, smaller ribosome, lack membrane bound compartments, generally have a cell wall, plasmids, flagella, pili, capsule.

Front 2

Describe coccus-shaped bacterium

Back 2

Round/spherical

Front 3

Describe bacillus-shaped bacterium

Back 3

Long , cylindrical capsillar-like

Front 4

Describe coccobacillus-shaped bacterium

Back 4

Elongated spherical bacterium. Rounded, but stretched.

Front 5

Described fusiform-shaped bacterium.

Back 5

Very long, thin bacterium.

Front 6

Describe vibrio-shaped bacterium.

Back 6

Long, thicker, curved bacteria.

Front 7

Describe spirillum-shaped bacterium.

Back 7

Thick, spiral-shaped bacterium.

Front 8

Describe spirochete-shaped bacterium.

Back 8

Thin, spiral-shaped bacterium.

Front 9

Describe a staphylococcus arrangement.

Back 9

A large, triangular arrangment of coccus bacteria.

Front 10

Describe a sarcina arrangement of coccus bacterium.

Back 10

A three-dimensional square of coccus bacterium.

Front 11

Give some key characteristics of a gram positive cell wall.

Back 11

Dies violet, blue. Dies due to thick peptidoglycan wall. The thick wall also prevents lysis of the cell, gives rigidity and shape. The only way it can be degraded is by a lysozyme. Teichoic and lipoteichoic acids serve as adhesins.

Front 12

Where are teichoic and lipoteichoic acids located and what do they do?

Back 12

Located in gram positive bacteria and serves as adhesins.

Front 13

Give some key characteristics of a gram negative cell wall.

Back 13

no peptidoglycan layer, so dies pink. Two cell membranes, an outer membrane and a cytoplasmic membrane sandwhiching a periplasmic space. Also containes porin proteins. LPS

Front 14

What are porin proteins and where are they located?

Back 14

Located in gram negative bacteria. Allow low molecular weight hydrophillic molecules through

Front 15

Describe the periplasmic space.

Back 15

Contains hydrolytic enzymes. Thin peptidolycan layer is protected by the outer membrane.

Front 16

What are the four major components of LPS?

Back 16

O polysaccharide, Lipid A, Core polysaccharide, outer membrane

Front 17

What are some of the key roles of lipid A of LPS?

Back 17

Anchors LPS to the outer membrane. However, upon cell deather, causes inflammation and can lead to cell death.

Front 18

What are some of the key roles of O polysaccharide of LPS?

Back 18

recognized by the immune system--can be varied by the pathogen to avoid immune detection.

Front 19

What is the difference between a smooth antigen and a rough antigen?

Back 19

smooth antigen are cells with the o polysaccharide and cells lacking the O polysaccharide are referred to as "rough" antigens.

Front 20

What is the major role of the outer membrane?

Back 20

it is a protective barrierthat prevents or slows the entry of harmful substances via porin proteins.

Front 21

What is another term for peptidoglycan?

Back 21

Murein

Front 22

Describe the structure of peptidoglycan.

Back 22

N acetyl muramic acid and N acetyl glucosamine strings linked together by (penta)peptide crosslinks.

Front 23

What are autolysins?

Back 23

autolytic enzymes produced by the cell

Front 24

Briefly describe Peptidoglycan synthesis.

Back 24

1. Precursors for peptidoglycan are constructed in the cell on a bactoprenol conveyor belt.
2. Bactoprenol transports assembled precursors to external cell surface.
3. Precursor attaches to the peptidoglycan chain and cross linked with peptides.
4. Break the blycan and peptide bonds in the chain with autolysins.
5. Add peptidoglycan precursor with transglycolases catalyst.
6. Transpeptidation -- cross-linking of the glycan chains

Front 25

What do transglycolases do?

Back 25

Catalyze the addition of peptidoglycan precursor into the glycan chain.

Front 26

What do transpeptidases do?

Back 26

catalyze the cross-linking of the glycan chains.

Front 27

What are PBP's?

Back 27

Transpeptidases that bind to penicillin and other beta lactam antibiotics. Responsible for extending peptidoglyca, creating a septum for cell division and for cell shape.

Front 28

Briefly describe the importance of autolysins in antibiotic use.

Back 28

Autolysins degrade the peptidoglycan layer in order to allowe new peptidoglycan to be inserted, even when peptidoglycan synthesis is blocked. This would lead to cell wall weakening and cell lysis.

Front 29

What is the primary role of the K-antigen in the capsule of a e. coli?

Back 29

inhibit phagocytic engulfment.

Front 30

What is the difference between a uniform and a non-uniform capsule?

Back 30

A uniform structure is one that is a polysaccharide capsule, whereas a "nonuniform structure" is a slime layer, or a more loosely adherent plysaccharide.

Front 31

What are the two primary functions of the capsule?

Back 31

Prevent against drying within an environment. In a host, the capsule prevents phagocytic engulfment.

Front 32

What are flagella made up of?

Back 32

Flagellin protein subunits.

Front 33

What is the difference between polar and peritrichous arranged flagella?

Back 33

Polar is a single flagellum on one side or flagella on two opposite sides of a bacterium. Peritrichous arrangment of flagella are fashioned around the entire bacterium.

Front 34

What type of subunits are pili made of up of?

Back 34

Pilin protein subunits.

Front 35

What are the differences between pili and flagella?

Back 35

pili are smaller and generally peritrichouse.

Front 36

Do gram positive or gram negative bacteria produce spores?

Back 36

Some gram positive produces spores. Never gram negative.

Front 37

Briefly describe spores.

Back 37

Spres are a survival mechanism that contain one copy of DNA and its essential cell for survival. They can be contained for a long time and germinate when conditions are favorable.