Lab 2-growth patterns, morphology, microscopy

Question 1

Approximately how many bacterial cells must be present for you to be able to observe a colony
on an agar plate with your unassisted eye?

Answer 1

> 1x106
cells

Question 2

Colony morphology uses which of the following descriptions to characterize colonies?

Answer 2

Colony texture, color and shape.

Question 3

what are the shapes of colony morphology?

Answer 3

circular,
irregular,
filamentous, and.
rhizoid.

Question 4

Which of the following best describes the colony morphology pictured below?

Answer 4

Filamentous colony, filamentous margin.

Question 5

Based on your in class observations, which of the following terms would you use to describe
Escherichia coli growth on agar slants? (Choose all that apply)

Answer 5

Mucoid

Question 6

A colony, like S. epidermidis, that which doesn’t allow light to easily pass through it would be
referred to as which of the following?

Answer 6

Opaque

Question 7

Cultures that grow with a clumpy morphology in broth are referred to as exhibiting which kind
of growth?

Answer 7

Flocculent

Question 8

Which of the following bacterial species which we inoculated exhibited the most robust growth
in nutrient broth culture?

Answer 8

E. coli

Question 9

Which of the following bacterial species which we inoculated exhibited no growth in nutrient
broth culture?

Answer 9

M. luteus

Question 10

The four magnification powers available on our bright-field, compound light microscopes are
which of the following?

Answer 10

40x, 100x, 400x and 1000x

Question 11

It is easiest to view fresh living bacterial species under the light microscope. T / F

Answer 11

False

Question 12

Fixing microbes for microscopic examination kills them.

Answer 12

True

Question 13

Wet mount slides are fixed before viewing. T/F

Answer 13

False

Question 14

Immersion oil may be used with any microscope power to enhance viewing. T / F

Answer 14

False

Question 15

M. luteus grown on nutrient agar slants has a translucent, friable appearance with a spreading
edge.

Answer 15

False

Question 16

Which of the following best describes how to properly prepare a wet mount slide?

Answer 16

Obtain a clean slide  place a single, small drop of culture onto the slide  gently drag an
edge of a cover slip along the slide surface until it touches the culture and spreads out 
gently lower the cover slip being careful not to trap many air bubbles

Question 17

. The minimum distance at which you can discern two objects as being separate in a light
the microscope is referred to as the

Answer 17

Resolution

Question 18

Name one bacterial species we inoculated in lab that exhibited sedimentation after growth in
nutrient broth.

Answer 18

E.coli

Question 19

If you have used immersion oil at 1000x magnification what must you do before you can again
use 400x power?

Answer 19

The immersion oil must be cleaned off before, going back to use the other objectives