Price Lectures Exam 1

Question 1

Infectious vs. contagious

Answer 1

Infectious–disease caused by living organism
Contagious–spreads from host to host
All contagious diseases are infectious, but not vice versa

Question 2

Disease carrier

Answer 2

organism that appears healthy but is shedding the virus

Question 3

What is virulence?

Answer 3

ability of organism to cause disease

Question 4

what is LD50? how does it relate to virulence?

Answer 4

LD50 is number of organisms needed to kill 50% of population;
a LOWER LD50= MORE virulent

Question 5

What does it mean if an organism is a facultative anaerobe?

Answer 5

is fine with or without oxygen

Question 6

The cell envelope consists of all layers outside the _____

Answer 6

cytoplasm

Question 7

What is the outer most layer of the envelope?

Answer 7

capsule

Question 8

What is the significance of the capsule? (2)

Answer 8

1) antiphagocytic (new infections)

2) important for serotyping

Question 9

When using the capsule for serotyping, what is the identifying structure?

Answer 9

K antigen

Question 10

Glycocalyx vs. slime layer? Function(s) of each?

Answer 10

Glycocalyx–> TIGHTLY bound onto capsule; for adherence

Slime layer–>LOOSELY bound; adherence and antiphagocytic

Question 11

Are flagella unique to gram positive or negative?

Answer 11

No; can be found or absent in either

Question 12

Important antigen of flagella?

Answer 12

H antigen

Question 13

What is phase variation?

Answer 13

Bacteria can change protein sequence of flagella to “hide” from antibodies made against original sequence

Question 14

What is Conjugation? What type of gene transfer is it?

Answer 14

exchange of genetic information using sex pilus;

horizontal gene transfer

Question 15

In conjugation, which cell produces the sex pilus?

Answer 15

the donor cell

Question 16

Which bacterial family lacks peptidoglycan?

Answer 16

Mycoplasma

Question 17

What two molecules alternate to make up the peptidoglycan backbone?

Answer 17

NAG and NAM

Question 18

The composition of which component of the peptidoglycan varies between spp?

Answer 18

tetrapeptide chain

Question 19

What are permeases?

Answer 19

proteins that regulates movement in and out of the cell (located in cytoplasmic membrane)

Question 20

Location of hydrolytic enzyme secretion:

1) Gram +
2) Gram -

Answer 20

1) into external medium

2) periplasmic space

Question 21

Detergents, polymyxins, and ionophores all target what bacterial structure?

Answer 21

cytoplasmic membrane

Question 22

2 reasons plasmids are relevant?

Answer 22

1) can encode antibiotic resistance

2) can encode virulence factors (i.e. toxins)

Question 23

tecichoic acids and endospores are unique to?

Answer 23

Gram positive bacteria

Question 24

3 functions of techoic acids?

Answer 24

1) bind Mg2+
2) autolysis
3) protection from antimicrobial peptides

Question 25

Name 4 structures unique to gram negative bacteria?

Answer 25

1) Lipoprotein 2) Outer membrane 3) Lipopolysaccharide (LPS) 4) periplasmic space

Question 26

Function of lipoprotein?

Answer 26

anchors outer membrane to peptidoglycan

Question 27

Function of outer membrane?

Answer 27

protects cell from host environment

Question 28

Name the 3 major abundance proteins found in outer membrane

Answer 28

1) Matrix porins 2) specific porins 3) Non-porin OM proteins

Question 29

Name the 3 portions of LPS

Answer 29

1) Lipid A 2) Core polysaccharide 3) O-specific polysaccharide (O antigen)

Question 30

This portion of LPS is the "endotoxin"

Answer 30

Lipid A

Question 31

Which portion of LPS shows the most variation between spp and confer antigenic specificity?

Answer 31

O-antigen

Question 32

Bacteriostatic vs. bacteriocidal

Answer 32

bacteriostatic--reversibly alters growth | bacteriocidal--irreversibly inhibits growth

Question 33

What are the 4 mechanisms of antibiotics

Answer 33

inhibit cell wall synthesis inhibit membrane function inhibit protein synthesis inhibit nucleic acid synthesis

Question 34

Penicillins, cephalosporins, bacitracin, cycloserine, vancomycin, and carbpenems mode of action?

Answer 34

inhibit cell wall synthesis

Question 35

Polymyxins, amphotericin B, ketoconazole, ionophores mode of action?

Answer 35

inhibit cell membrane function

Question 36

Which drug is anti-fungal?

Answer 36

Amphotericin B

Question 37

Aminoglycosides, tetracyclines, chloramphenicol, erythromycin, and clindamycin mode of action?

Answer 37

inhibit protein syntesis

Question 38

Which drugs target the SMALL ribosome subunit?

Answer 38

aminoglycosides and tetracyclines

Question 39

which drugs target the LARGE ribosome subunit?

Answer 39

chloramphenicol, erythromycin, and clindamycin

Question 40

Fluoroquinolones, rifampin, sulfonomides, trimethoprim, and metronidazole mode of action?

Answer 40

inhibit nucleic acid synthesis