General

Question 1

A “nucleotide” refers to a three component structure containing what?

Answer 1

a sugar,
a phosphate, and
a nitrogenous base.

Question 2

ADNA nucleotideincludes a nitrogenous base ion one of four forms. Name the four types of bases.

Answer 2

adenine (A), thymine (T),

cytosine (C), guanine (G),

Question 3

There are two TYPES of nitrogenous bases.

What are they?

Answer 3

purines and pyrimidines.

Twopurines (adenine and guanine)
Twopyrimidines (cytosine and thymine)

Question 4

In rna the nitrogenous base thymine is replaced by

Answer 4

Uracil (U)

Question 5

T/F

Staphylococcus are nonmotile and non–spore forming organisms.

Answer 5

TRUE

Question 6

“Competent”cells arebacterialcells that can do what?

Answer 6

accept extra-chromosomal DNA or plasmids (naked DNA) from the environment.

Question 7

Name two Staphylococcal GPC’s producing a polysaccharide capsule.

Answer 7

S. aureus
S. epidermidis

Both produce a polysaccharide capsule that inhibits phagocytosis. The capsule may appear as a slime layer or biofilm and allows the organisms to adhere to inorganic surfaces and impairs or inhibits the penetration of antibiotics.

Tille, Patricia. Bailey & Scott’s Diagnostic Microbiology (p. 790). Elsevier Health Sciences.

Question 8

Most strains of S. aureus produce this toxin, that disrupts smooth muscle in blood vessels.

Answer 8

alpha toxin

Question 9

Most strains of S. aureus produce alpha toxin, which disrupts smooth muscle in blood vessels and is toxic to ____________, ___________, ____________, and ____________.

Answer 9

erythrocytes,
leukocytes,
hepatocytes, and
platelets.

Question 10

Staphylococcal species produce a variety of cytotoxins including these four.

Answer 10

alpha toxin,
beta toxin,
delta toxin, and
gamma toxin.

Question 11

Protein A serves as a virulence factor for S. aureus because Protein A does what?

Answer 11

Protein A has an affinity for Fc receptor of IgG and complement. As such it effectively “inverts” IgG, neutralizing the role of IgG in promoting phagocytosis.

Question 12

S. aureus is coagulase-positive. Name three other coagulase-positive or variable staphylococci that are normal microbiota of a variety of animal species, including dogs.

Answer 12

Staphylococcus intermedius,
Staphylococcus pseudintermedius, and
Staphylococcus delphini.

Question 13

The most common CoNS is likely what?

Answer 13

S. epidermidis is the most commonly encountered Coagulase Neg Staph’

Tille, Patricia. Bailey & Scott’s Diagnostic Microbiology E-Book (p. 795).

Question 14

Infections involving implanted medical devices usually involve what three Staphylococcal species?

Answer 14

S. epidermidis and, less commonly,
S. haemolyticus and
S. lugdunensis,

Tille, Patricia. Bailey & Scott’s Diagnostic Microbiology E-Book (p. 796). Elsevier Health Sciences.

Question 15

This organism is most frequently associated with community-acquired urinary tract infections in young, sexually active females but is not commonly associated with HAIs (health care–associated infections).

Answer 15

S. saprophyticus

Question 16

What re the two most common pathogens associated with UTI’s in women.

Answer 16

1) Escherichia coli (most common)

2) S. saprophyticus

Question 17

Name two normal microbiota of the skin considered harmless saprophytes; that may also act as opportunistic pathogens.

Answer 17

Micrococcaceae

Dermacoccaceae

Question 18

A erythrocyte, is commonly known as a…

Answer 18

red blood cell

Question 19

A leukocyte is commonly known as a…

Answer 19

white blood cell

Leukocytes are nucleated amoeboid white blood cells.