Lab 3.1: Bacteria Motility

Question 1

What allows observation of living cells to determine motility?

Answer 1

-simple wet mounts
-hanging drop technique

Question 2

What else can be observed other than motility?

Answer 2

-cell size and shape
-arrangement
-binary fission

Question 3

Wet mount preparation is made by:

Answer 3

-placing a drop of water on a slide and covering it with a cover glass
-since no stain is used, most cells are transparent

Question 4

Motility can be observed at a ?? or ??-dry magnification, but viewing must be done quickly because the preparation will dry out in ??-?? minutes

Answer 4

-low or high
-15-20 minutes

Question 5

Swimming bacteria will move ?? of one another, either in a straight line, ??, or random path

Answer 5

-independently
-zigzag

Question 6

A hanging drop preparation allows a ?? observation of the specimen because?

Answer 6

-longer
-it does not dry out as quickly

Question 7

Brownian motion:

Answer 7

-created by collisions between cells and water molecules
-cells will appear to vibrate in place

Question 8

What kind of cells should exhibit Brownian motion?

Answer 8

-nonmotile cells

Question 9

Complications that can happen when observing wet mounts or hanging drop:

Answer 9

-cells are not moving because they are stuck to glass
-cells are streaming across the field in the same direction
-cells are packed together and not moving

Question 10

True or False:
A hanging drop is best viewed with as much illumination as possible.

Answer 10

-false

Question 11

True or false:
Bacterial motility using a wet mount preparation can be observed even an hour or so after the specimen has been prepared

Answer 11

-false

Question 12

Select all the cellular features from bacteria that can be observed when using a wet mount and/or hanging drop preparations. (5)

Answer 12

-binary fission
-size
-morphology
-motility
-arrangement

Question 13

Simple wet mount and hanging drop preparations allow observation of ______________________ to determine ______________________.

Answer 13

-living cells
-motility

Question 14

True or False:
You can easily observe bacterial flagella using both the wet mount and hanging drop preparations.

Answer 14

-false

Question 15

True or False:
A bacterial specimen that has been heat-fixed and stained is useful to determine motility.

Answer 15

-false

Question 16

True or False:
Bacterial motility using a hanging drop preparation can only be observed for around 5 minutes after the specimen has been prepared.

Answer 16

-false

Question 17

True or False:
A wet mount is best viewed with as little illumination as possible.

Answer 17

-false

Question 18

True or false:
A wet mount preparation is made by placing the specimen in a drop of immersion oil on a glass slide and covering it with a cover glass.

Answer 18

-false

Question 19

In a hanging drop preparation, the ________________________ forms an air tight seal that slows drying of the water drop.

Answer 19

-petroleum jelly