Bacteria

Question 1

Prokaryotes lack….

Answer 1

Cell Membrane

Question 2

How do bacteria divide?

Answer 2

Transverse Fission

Question 3

Bacilli

Answer 3

Rod-shaped Bacteria

Question 4

Cocci

Answer 4

Spherical Bacteria

Question 5

What are the actin homologues in bacterial cytoskeleton?

Answer 5

mreB, parM. They are required for chromosome/plasmid segregation

Question 6

What is a clone?

Answer 6

A population derived from a single cell.

Question 7

Strain

Answer 7

A clone that is genetically different from other clones of the same species

Question 8

Isolate

Answer 8

A clone cultured from a patient with infection

Question 9

Serotype

Answer 9

Clone characterized by specific forms of important surface structures recognized by immune system.

Question 10

What are permeases?

Answer 10

Transport proteins in the plasma membrane required to transport small molecules into the cell

Question 11

Peptidoglycan monomer

Answer 11

N-acetyl-glucosamine (NAG) - N-acetyl-muramic acid (NAM). NAM has a side chain of 5 amino acids containing D-Ala-D-Ala-COOH

Question 12

Penicillin

Answer 12

Structural analogue of the D-ala-D-ala of peptidoglycan side chains

Question 13

Penicillin’s mechanism of action

Answer 13

Binds active site of cross linking enzyme and forms irreversible covalent bond, inactivating the enzyme. Can only work on growing cells.

Question 14

Gram Positive bacteria

Answer 14

Bacteria with thick peptidoglycan 20-50 layers

Question 15

Gram Negative Bacteria

Answer 15

Bacteria with thin peptidoglycan 1-3 layers

Question 16

Gram Stain Procedure

Answer 16

1) Heat fix bacteria to slide
2) Stain with Genetian or crystal violet (stains all bacteria)
3) Add Iodine ‘Mordant’ complexes with dye
4) Decolorize - dye/iodine complexes leak through thin peptidoglycan
5) Counterstain with red dye (safranin)

Question 17

Color results of Gram stain

Answer 17

Gram postive - purplish blue

Gram negative - Red

Question 18

Protein Fibrillae

Answer 18

found in envelopes of gram positive bacteria and adheres to mammalian cells and extracellular matrix; many types per cell. Covalently bound to peptidoglycan.

Question 19

Teichoic acids

Answer 19

found in envelopes of gram positive bacteria. Polymers of sugar alcohols linked by phosphate groups

Question 20

Where is the peptidoglycan found in gram negative bacteria?

Answer 20

It is found in the periplasm.

Question 21

What is the periplasm

Answer 21

Space between the two lipid bilayer membranes filled with enzymes, solute carrier proteins, polysaccharides.

Question 22

What makes up the outer membrane?

Answer 22

Inner leaflet- typical phospholipids

Outer leaflet- composed entirely of lipopolysaccharide (LPS)- disaccharide with attached fatty acids.

Question 23

What does LPS compose of?

Answer 23

1) O-antigen: polymer, repeat of 3-5 sugars
2) Core: phosphorylated complex oligosaccharide; adjacent units bonded via divalent cations
3) Lipid A

Question 24

What is Lipid A?

Answer 24

disaccharide + 6-8 saturated fatty acids. TOXIC. endotoxin because it is physically part of the cell wall and released by lysis.

Question 25

What is the Jarish-Herxheimer reaction?

Answer 25

Antibiotic treatment kills bacteria, can result in release of endotoxin and other inflammatory components causing fever and hypotension.

Question 26

Three bacterial appendages

Answer 26

Flagella-Locomotion
Pili (fimbrae) - adhesion
Conjugation pili - transfer of DNA between cells

Question 27

Bacterial spores

Answer 27

Specialized cells for dispersal, resisting unfavorable environments. Resistant to boiling, disinfectants! MADE ONLY BY GRAM POSITIVE BACTERIA

Question 28

Bacterial chemotaxis

Answer 28

Counter clockwise: smooth swimming

Clockwise: random tumbling