bio laB FINl

Question 1

Basic lab techniques - What is complex media?

Answer 1

the exact media varies from batch to batch

Question 2

Basic lab techniques - What is agar?

Answer 2

A red algea extract, makes things solidify

Question 3

What are the 5 types of slants? arborescent, beaded, enchinulate, filiform, rhizoid, spreading

Answer 3

branched, beaded, pointed, even, rootlike, spreading

page 3

Question 4

5 types of broth? Look in book to memorize

Answer 4

you said it page 4

Question 5

3 types of deep characteristics?

Answer 5

page 4

Question 6

How to do a t streak?

Answer 6

draw it out it’s easier that way

Question 7

Texture, form, elevation, margin of agar plate colonies

Answer 7

page 8

Question 8

How to do a lawn incolulum?

Answer 8

it’s easier to do it irl.

Question 9

Label microscope

Answer 9

page 13

Question 10

How do you use an oculat micrometer?

Answer 10

each small click is 1um at 100x (1000), 2.5 at 40x (400), 10 at 10x (100), and 25 at 4x (40)

Question 11

What is the process of oil immersion?

Answer 11

the specimen makes light bounce around, and not into the objective. The oil makes the light refect into the objective

Question 12

The shapes, Spirillium, rod, bacillus, coccus

Answer 12

Look it up

Question 13

What is a simple stain?

Answer 13

A stain used to create contrast between the specimen and it’s background. Used to determine cell morphology, size, and arrangement.

Question 14

What is a direct stain? Example?

Answer 14

A stain that stains the bacterium itself. Methylene blue

Question 15

What is a negative stain? Example?

Answer 15

Another simple stain that colours the background. Nigrosin. Does not require heat fixing.

Question 16

Gram stain - What is a gram stain?

Answer 16

Differentiates bacteria into two main groups based on the composition of their cell wall. Gram positive and gram negative.

Question 17

Gram stain - what are the steps?

Answer 17

1. treatment with crystal violet.
2. treatment with iodine
3. treatment with alcohgol

treatment with sanfranin

Question 18

Gram stain - what does treatment of crystal violet accomplish?

Answer 18

step 1. crystal violet particles get trapped in the peptidoglycan layer of the cell wall. Gram positive bacteria have a thick layer of peptidoglycan and as a consequence trap the dye particles. In gram negative, the outer membrane only allows a few particles to pass . The negeative charge on the outer surcacfe of the cell attracts the crystal violet, though.

Question 19

Gram stain - what does treatment with iodine accomplish?

Answer 19

step 2.

Iodine is a mordant. It combines to stain to help increae the intensity of the primary stain. Heat is sometimes the mordant. In the gram reaftion, iodine is. Iodine causes the crystal violet particles to increase in size and be trapped more effectively by the peptoglycan.

Question 20

Gram stain - what does treatemnet with alcohol do?

Answer 20

step 3.

This is the destaining step. The ethanol will effect gram negative and gram positive cell walls differently. Ethanol shrinks the pores of the peptidoglycan layer in gram positive organisms leaving the crystal violet/iodine complex trapped. In gram negative organisms, the ethanol disrupts the outer membrane, allowing the crystal violet to be washed out

Question 21

Gram stain - what does safranin do?

Answer 21

step 4.

Basic counterstain. A final straining step required to colour those bacteria that were de-stained. Safranin does nothing to the already stained cyrstal violet, so those remain purple.

Question 22

Bacterial morphology

Answer 22

page 22

Question 23

Ecoli is gram ____ and B sub is gram _____

Answer 23

negative positive