Introduction To Bacteriology

Front 1

Regarding the size of bacteria

Back 1

larger than a virus, smaller than yeast and RBCs; they are about 1uM

Front 2

What is Koch's postullate?

Back 2

A specific organism causes a specific disease.

Front 3

What divides all living organisms into Prokaryotes vs. Eukaryotes?

Back 3

The presence or absence of a nuclear membrane

Front 4

What kind of ribosomes do bacteria have? What about humans?

Back 4

Bacteria have 70S ribosomes. We have 80S

Front 5

What are the main characteristics distinguishing prokaryotes from eukaryotes?

Back 5

prokaryotes are unicellular, they lack membrane bound organelles, small ribosome, a peptidoglycan cell wall, small haploid genome single circular DNA chromosome, lack of a nuclear membrane.

Front 6

What is defined growth in the lab?

Back 6

all components are known.

Front 7

What is complex growth?

Back 7

contains some ingredients of unknown chemical composition. LIke blood agar.

Front 8

What is selective growth?

Back 8

Favors the growth of a particular organism based on nutrition requirements.

Front 9

Differential growth media

Back 9

distinguishes between different groups of bacteria.

Front 10

How do you Gram stain?

Back 10

1. crystal violet, fix with KI, decolorize with Etoh, counterstain with safranin

Front 11

How do you acid fast stain?

Back 11

carbachol fuchsin, decolorize with acid-alcohol (acid fast remain red); counterstain with methylene blue.

Front 12

What are the different kinds of flagella?

Back 12

monotrichous (single polar) amphitrichous (one at each end) lophotrichous (one or more at each pole) peritrichous (distributed over entire surface)

Front 13

Why use the acid fast stain?

Back 13

for organisms that dont gram stain well and have a high lipid content.

Front 14

Which Gram positive bacteria undergo sporulation?

Back 14

Bacillus and Clostridium.

Front 15

What are the three parts of a flagella?

Back 15

Filament (made of flagellin subunits), hook and basal body (anchors the flagella into the cell wall and membrane).

Front 16

The hook and basal motor proteins control what?

Back 16

movement, like a propellar.

Front 17

the energy derived for flagellar motion comes from where?

Back 17

PMF

Front 18

Structure of basal body differs between what?

Back 18

G+ and G-

Front 19

What is a function of flagella?

Back 19

chemotaxis

Front 20

What is the flagellar protein?

Back 20

Also called the H antigen, highly antigenic, used for distinguishing different types of G- bacteria.

Front 21

Spirochetes have what?

Back 21

endoflagella or axial filaments.

Front 22

what do pilli or fimbrae do?

Back 22

They are involved in cell attachment to the host surfance.

Front 23

WHat is important about the membranes of bacteria?

Back 23

They contain no sterols!

Front 24

WHat is the function of the cell wall?

Back 24

give shape and rigidity to bacteria and help them to withstand osmotic stress.

Front 25

What is the basic unit of peptidoglycan?

Back 25

Composed of two sugar derivatives: NAG and NAM linked by a B1-4 glycosidic bond.

Front 26

Gram - bacteria have ________ in their cell wall.

Back 26

diaminopimelic acid. DAP

Front 27

Gram + bacteria have _______ in their cell wall.

Back 27

Diamino acid lysine.

Front 28

What is the nature of the peptide bond in Gram - bacteria?

Back 28

direct peptide bond between DAP and the terminal alanine on the adjacent peptidoglycan unit.

Front 29

What is the nature of the peptide bond in Gram + cell wall?

Back 29

Peptide bridge.

Front 30

Peptidoglycan cell synthesis occurs where?

Back 30

Both inside and outside the cell membrane.

Front 31

What is bactoprenol?

Back 31

A lipid carrier.

Front 32

What are the steps for cell wall synthesis?

Back 32

bactroprenol P attached via a PDE bridge to NAM which is linked to pentapeptide. NAG is then attached. (In G+ bacteria the pentapeptide bridge is also added) Bactoprenol helps move across the membrane, gets dephosphorylated and moves back in the cell. Last step: cross link by transpeptidase which removes the terminal alanine on the NAM peptide.

Front 33

What does bacitracin do?

Back 33

It blocks dephosphorylation of bactoprenol.

Front 34

What two acids do Gram + bacteria have in their cell wall?

Back 34

Teichoic and Lipoteichoic.

Front 35

Structure of G - outer membrane?

Back 35

Lipid A, core polysaccharaide, O-specific polysacch, porins and periplasm.

Front 36

What's important about the outer membrane in Gram -?

Back 36

forms a barrier to hydrophobic compounds, relatively permeable for small hydrophilic compounds.