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Micro Exam #2 > Morphology and Ultrastructure > Flashcards

Flashcards in Morphology and Ultrastructure Deck (85)
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1

Average size of a bacterium?

1 uM

2

List a few unique cellular features of Bacteria?

Lack of nucleus and other membranes organelles
DS circular DNA
Smaller Ribosomes (70S)
Plasmids

3

In gram staining, what colors do positive and negative turn?

Purple = Positive
Red = Negative

4

What two criteria are primarily used for classification?

Size/shape
Gram +/-

5

What do you do in a gram stain?

Smear, Heat fixation, crystal violet + iodine, wash, safranin

6

What makes a gram + purple?

Stain gets trapped in the thick, cross-linked peptidoglycan layer.

7

What stain you yo use for mycobacterium?

Acid-Fast Staining

8

How (what lab technique) would you use to assess bacterial genetics? When would this be important?

PCR
Esp. Important for slow growing strands

9

The lack of a bacterial nuclear membrane allows for...

Coupled Transcription and Translation

10

Location of DNA in the bacterial cell?

the nucleoid and plasmids

11

Size of two subunits and full ribosome complex?

30S + 50S = 70S

12

With the exception of myco, what do bacterial cell membranes lack?

Steroids

13

Three important roles of the bacterial lipid bilayer?

Electron Transport/Energy Production
Pumps present to maintain internal environment
Lined internall with actins that determine shape/division

14

Describe a G+ cell wall

Thick, multilayered
Mostly Peptidoglycan
Teichoic Acids Make covalent linkages and anchor to membrane

15

What does lysozyme do to fight bacteria?

Cleaves glycan backbone of peptidoglycan
Death by loss of osmotic control

16

Are peptidoglycan and techoic acid still present in gram negs?

A little PG
No TA

17

What parts of PG binds to provide crosslinkage?

D-Ala to Lys

18

Two repeating subunits in PG?

NAG and N-Acetylmuranic Acid

19

Importance of the periplasmic space in gram negatives?

Breakdown molecules (proteases, phosphotases, lipases)
Many lytic virulence factors

20

Type ___ virulence factors are a major virulence factor

III

21

Describe the outer membrane of a gram negative.

Inside normal, outside LPS

22

LPS is also known as ______. When released it triggers a _______.

Endotoxin
Schwartzman Rxn

23

What is LPS without its O antigen?

LOS (lipooligosaccharide)

24

What are the transmembrane proteins called? What gets through them?

Porins.
Materials under 700 Da

25

Role of lipoproteins in G- bacteria?

Hold outer membrane onto the bacteria

26

How is LPS crosslinked?

Mg and Ca linkages between phosphates

27

What is a bacterial capsule?

A loos polysaccharide or protein layer
"Glycocalyx"

28

Why do we can about bacterial capsules?

Poorly Antigenic
Anti-phagocytotic
Increase Adherance -- Biofilms in quorum

29

What are flagella?

Ropelike cellular propellers made of heavily coiled flagellin.
Driven by ATP motor and chemotactic signals

30

What are fimbriae?

Hair-like projections outside the cell made of Pilin.