Micro - Basic Bacteriology (Bacterial Structures & Cell Walls) Flashcards Preview

FA - Microbiology > Micro - Basic Bacteriology (Bacterial Structures & Cell Walls) > Flashcards

Flashcards in Micro - Basic Bacteriology (Bacterial Structures & Cell Walls) Deck (23):
1

What is the function of peptidoglycan?

Gives rigid support, protects against osmotic pressure

2

What is the chemical composition of peptidoglycan?

Sugar backbone with peptide side chains cross-linked by transpeptidase

3

What is the clinically relevant function of cell wall/cell membrane in gram positives versus gram negatives?

GRAM + = Major surface antigen; GRAM - = Major surface antigen AND Site of endotoxin (LPS)

4

What is the unique substance contained in gram positive cell wall/cell membrane, and what does it induce?

Lipoteichoic acid, induces TNF & IL-1

5

What is the unique substance contained in gram negative cell wall/cell membrane? What are its major parts, and what is the significance of each of these parts?

Endotoxin = LPS = Lipid A & O polysaccharide; Lipid A induces TNF & IL-1; O polysaccharide is the antigen

6

For what is bacterial plasma membrane used as a site? What is the chemical composition of the bacterial plasma membrane?

Site of oxidative and transport enzymes; Phospholipid bilayer

7

What function does the bacterial ribosome have? What is its structure?

Protein synthesis; 50S and 30S subunits

8

What is periplasm, and in what kind of bacteria is it found? What does it contain?

Space between the cytoplasmic membrane and outer membrane in gram-negative bacteria; Contains many hydrolytic enzymes, including Beta-lactamases

9

What function does a bacterial capsule have? What structure/composition does it typically have? What bacteria's capsule is an exception, and what kind of structure/composition does it have?

Protects against phagocytosis; Polysaccharide; Except Bacillus anthracis, which contains D-glutamate

10

What function do pilus/fimbria serve? More specifically, what function does a sex pilus serve? What is the structure of a pilus/fimbria?

Mediate adherence of bacteria to cell surface; Sex pilus forms attachment between 2 bacteria during conjugation; Glycoprotein

11

What function does flagellum have? What is its structure/composition?

Motility; Protein

12

What advantage/function do spores have? What is their structure?

Resistant to dehydration, heat, and chemicals; Keratin-like coat, Dipicolinic acid, Peptidoglycan

13

What do plasmids contain? What is their structure?

Contains a variety of genes for antibiotic resistance, enzymes, and toxins; DNA

14

What function does Glycocalyx have? What is its structure/composition?

Mediates adherence to surfaces, especially foreign surfaces (e.g., indwelling catheters); Polysaccharide

15

Name 6 structures/substances that can be common to both gram-positive and gram-negative bacteria?

(1) Cytoplasmic membrane (2) Peptidoglycan (3) Capsule (4) Pilus (5) Flagellum (6) Cell wall (although thicker and more extensively cross linked in gram-positive bacteria)

16

Name one structure/substance that is unique to gram-positive organisms.

Lipoteichoic acid (combination of lipids and teichoic acids)

17

Name two structures/substances that are unique to gram-negative organisms.

(1) Endotoxin/LPS (in outer membrane) (2) Periplasm

18

What advantage/function do spores have? What is their structure?

Resistant to dehydration, heat, and chemicals; Keratin-like coat, Dipicolinic acid, Peptidoglycan

19

What do plasmids contain? What is their structure?

Contains a variety of genes for antibiotic resistance, enzymes, and toxins; DNA

20

What function does Glycocalyx have? What is its structure/composition?

Mediates adherence to surfaces, especially foreign surfaces (e.g., indwelling catheters); Polysaccharide

21

Name 6 structures/substances that can be common to both gram-positive and gram-negative bacteria?

(1) Cytoplasmic membrane (2) Peptidoglycan (3) Capsule (4) Pilus (5) Flagellum (6) Cell wall (although thicker and more extensively cross linked in gram-positive bacteria)

22

Name one structure/substance that is unique to gram-positive organisms.

Lipoteichoic acid (combination of lipids and teichoic acids)

23

Name two structures/substances that are unique to gram-negative organisms.

(1) Endotoxin/LPS (outer membrane) (2) Periplasm (space between cytoplasmic membrane and outer membrane in gram-negative bacteria; Contains many hydrolytic enzymes, including Beta-lactamases)

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