Lab Practical 2

Question 1

Describe the process for the water quality tests: Presumptive and Confirmed coliform.

Answer 1

Presumptive: add water samples to phenol red lactose broth.
Confirmed: Inoculate an EMB plate with broth from the tubes that produced acid and gas.
Dark growth with a metallic sheen is a probable coliform.

Question 2

Answer 2

candida

Question 3

Describe the procedures used for an indirect and a direct (sandwich) ELISA.

Answer 3

1. Either the antibody (direct) or antigen (indirect) is stuck to the bottom of the well.
2. Add sample, wait, then wash
3. add antibody solution, wash
4. add color reagent

Direct: antibody, antigen, antibody
Indirect: antigen, antibody, antibody

Question 4

Answer 4

taenia

Question 5

Answer 5

Schistosoma

Question 6

Answer 6

enterobius

Question 7

Answer 7

plasmodium

Question 8

Motility structures of protozoa

Answer 8

Cilia and flagella

Question 9

Know what the results of a positive MR and VP tests would look like and what products in general are produced by a positive result. At what pH (acidic or basic) is “methyl red” red. What sugar is fermented in these tests?

Answer 9

Positive MR result: Red broth
Positive VP result: Red broth
Acids are produced in a positive result
Methyl red is red at a acidic pH
Glucose is fermented

Question 10

Describe how to set up a Kirby-Bauer (disk diffusion) antibiotic susceptibility test. Describe what is meant by confluent growth and how we “seed” a plate. Know what is meant by the zone of inhibition and know how it is measured.

Answer 10

Inoculate the entire plate and lay labeled antibiotic disks on the lawn. The zone of inhibition indicates sensitivity to antibiotics and is measured in millimeters across the diameter of the zone.

Question 11

Answer 11

giardia

Question 12

Describe how an ELISA is different from the Western blot technique.

Answer 12

No electrophoresis in ELISA

Question 13

Answer 13

trichomonas

Question 14

Answer 14

taenia

Question 15

Answer 15

rhizopus

Question 16

What do the letters in SIM stand for and what reaction does each symbolize? What do positive results for the “S” and “M” look like?

Answer 16

S: sulfur reduction
I: Indole production
M: Motility
Positive sulfur is a black tube
Positive motility is a hazy tube

Question 17

Answer 17

penicillium

Question 18

Answer 18

entamoeba

Question 19

Which type and genus of helminths have proglottids and a scolex?

Answer 19

cestode/tape worm

Question 20

Know what a positive result for indole would look like and what amino acid is broken down to produce indole. What enzyme is present? What reagent is added?

Answer 20

-red layer at the top of tube after adding reagent
-tryptophan
-tryphtohanase
-Kovacs reagent

Question 21

Answer 21

aspergilllus

Question 22

Know what is meant by drug synergy and how it could be described.

Answer 22

When two drugs work better in combination than alone

Question 23

Answer 23

trypanosoma