Bacterial identification through functional media - motility testing

Question 1

T/F : Functional media are used to identify unknown microbes.

Answer 1

T

Question 2

T/F: Motility tests are conducted with soft gel media.

Answer 2

T

Question 3

T/F: Clear media is a positive test result for motility.

Answer 3

F, turbid is positive

Question 4

T/F: all motile bacteria have one or more flagella.

Answer 4

False

Question 5

Gel that prevents the diffusion of some microbes.

Answer 5

Motility media

Question 6

Bacteria with a single flagellum at each end.

Answer 6

Amphitrichous

Question 7

Bacteria with numerous flagella at one end.

Answer 7

Lophotrichous

Question 8

Agents that prohibit the growth of some microbes

Answer 8

Selective media

Question 9

What are the three primary types of functional media?

Answer 9

Selective, differential, enriched

Question 10

What is selective media?

Answer 10

Selective media contain agent(s) that prohibit the growth of some organisms, thus selecting or allowing the growth of other organisms. This is especially helpful when growing mixed cultures containing many different microbes when only one or two specific microbes are of interest.

Question 11

What is differential media?

Answer 11

Differential media enable many types of microbes to grow; however, differential media contain an indicator that enables differences between microbes to be visualized.

Question 12

What are enriched media?

Answer 12

Enriched media are supplemented with essential growth factors for organisms that do not grow well on typical media.

Question 13

_____ is a form of functional media used to identify unknown microbes.

a.) Selective
b.) differential
c.) enriched
d.) all above

Answer 13

d

Question 14

_____ media contain an indicator that enables differences between microbes to be visualized.

Answer 14

Differential

Question 15

How do bacteria move?

Answer 15

acteria move by a variety of mechanisms including flagella, axial filaments, and slime secretions

Question 16

_____ bacteria have flagella distributed all over the surface of the cell.

Amphitrichous

Monotrichous

Peritrichous

All of the above

Answer 16

Peritrichous

Question 17

T/F : Growth only along the stab line is a negative test for motility.

Answer 17

T

Question 18

Motility media is a _____ used to detect bacterial movement.

Answer 18

soft gel

Question 19

_____ is a positive test result when using motility media.

Answer 19

Turbidity

Question 20

How does the agar media used for motility testing differ from that used for your plate cultures?

Answer 20

Functional motility media is used for conducting motility tests. The functional motility media is a soft gel consisting of 0.4% agar. The gel consistency allows motile bacteria to move throughout the media while preventing diffusion of non-motile species. The functional motility media differs from that of the plate agar because the plate agar uses a solid media agar and is primarily used for culturing microbes and typically consists of 1.5 - 2.0% agar.

Question 21

What can you conclude regarding the motility of E. coli and S. epidermidis based on your results?

Answer 21

Since the E. coli did not present a clear stab line, and maintained a turbid color throughout the tube, the E. coli was positive for the motility test. In other words, the E. coli experienced growth throughout the tube, thereby indicative of motility. The S. epidermidis has a negative result because it had a clear stab line and the tube had a turbulent appearance only at the stab line, thereby indicating microbial growth only at the stab line and a lack of motility.

Question 22

_____ media contain agent(s) that prohibit the growth of some microbes.

Answer 22

Selective

Question 23

t/f Motility media is an example of differential media because it enables differences between microbes to be visualized.

Answer 23

T

Question 24

T/F Motility is an important characteristic for classifying microbes.

Answer 24

T

Question 25

A _____ bacteria has a single flagellum.

Answer 25

Monotrichous

Question 26

Motility media prevents the diffusion of _____ microbes.

Answer 26

non-motile

Question 27

Motility media is inoculated by _____.

Answer 27

Stabbing a culture with media

Question 28

A _____ is a positive result for bacterial motility when using motility agar.

Answer 28

turbid gel