Name:_______________________

PID #________________________

 

Quiz #1: Labs 1-4

 

 

1.      Choose EITHER A or B.

 

A.     If you are looking at an organism under the 100x objective lens, how magnified is the organism?

B.     Why do we use oil on the 100x objective lens of the microscope?

 

 

 

 

 

 

2.      Match the components of the Gram stain with their function. Each blank may have more than one answer, thus each letter may be used more than once.

 

      ___ stains gram positive bacteria                                            A. safranin

 

___ stains gram negative bacteria                                           B. iodine

 

___ decolorizes                                                                       C. 95% ethyl alcohol

 

___ creates large crystal complexes                                        D. crystal violet

 

 

Use the table below to answer question 3. 

tube #	volume plated	dilution factor	# colonies counted	# colonies per ml of original sample
1	0.1 ml	10-6	150	?
3	1.0 ml	10-7	?	7.2 x 108

 

 

3.      Answer BOTH parts A and B. Show your work.

 

1. How many bacterial colonies per ml were in the original sample from tube #1?

 

 

 

2. How many colonies did you count from 1.0 ml of tube #3?

 

 

 

4.      How do bacteria acquire antibiotic resistance? (1-2 sentences max!)

 

 

 

 

 

5.      From what you have learned in lab (or class), give the name of one organism and the disease it causes.