Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

BIO3124 > Microscopy > Flashcards

Microscopy Flashcards

1
Q

Positive Staining

A
  • Positive charges interact with negative charges.

- Staining the specimen.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Negative Staining

A
  • Negative charges interact with positive charges.

- Staining the background.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What does the simple staining method allow us to determine?

A
  • Shape, size and grouping of cells.

- There is no color discrimination.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Differential staining

A

Divides bacteria into two… gram negative and gram positive.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

In differential staining, how can we find out if an organism doesn’t have a cell wall based on just the colors we observe?

A
  • If it has cell wall –> might be purple or red.

- If it does not have cell wall –> it will only be red.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What type of bacteria do the colors indicate in differential staining?

A
  • PURPLE: Gram positive = bacteria with 1 cell wall and 1 membrane
  • RED: Gram negative = bacteria with 1 cell wall and 2 membranes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Gram +ve bacteria that contain high G+C content.

A
  • Rod/Bacillus

- Mycobacterium (Genus)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Gram +ve bacteria that contain low G+C content?

  • Shape + sporulation.
A
  • Rod/Bacillus:
    Sporulating genera:
    1. Bacillus
    2. Clostridium

Non-Sporulating:

  1. Lactobacillus
  2. Listeria
  • Coccus/Sphere:
    1. Streptococcus
    2. Staphylococcus
    3. Micrococcus
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Gram +ve bacteria that contains high G + C content?

A
  • Rod/Bacillus

1. Mycobacterium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

The 3 basic rules

A
  1. If the genus contains “coccus”, it is most likely going to be gram +ve.
  2. If the genus contains “bacillus”, it is most likely a gram +ve rod.
  3. If the two rules above don’t line up with the specimen, then it is gram -ve rod.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Gram negative bacteria…

A
  • Proteobacteria
  • Bacteroids
  • Chlamydia
  • Spirochetes
  • Cyanobacteria
  • Green/purple sulfur bacteria
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are the only coccus bacteria in Gram negative?

A
  • Neisseria (diplococcus)
  • Moraxella
  • Acinetobacter
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are the shapes of bacteria found in gram -ve and gram +ve?

A

Gram -ve: Mostly rods with a few exceptions (3).

Gram +ve: Contains both rods and cocci.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Difference between Gram -ve and Gram +ve cell walls…

A

Gram -ve: Thin cell wall with external cell membrane (Lipopolysaccharide)

Gram +ve: Thick cell wall without external membrane.

i.e. the thicker the cell wall, the more peptidoglycan the cell carries.

** see notes for comparison

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Gram Staining steps…

A

Refer to notes for full details.

  1. Crystal Violet (+ charged): electrostatically interacts with PM
  2. Gram’s Iodine: Forms larger complex with Crystal Violet to prevent it from diffusing out of the cell wall.
  3. Alcohol wash to trap complex… If dyed comes out, the cell mostly likely has an external lipid bilayer.
  4. Safarin stain (+ charged): added to make makes gram -ve red and gram +ve purple.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Diagnostic staining of mycocbacteria

A

Since its cell wall is impermeable due to mycolic acid, we have to use Acid Fast Staining.

17
Q

Main Steps of acid fast staining

A
  1. Make call well more permeable via heat
  2. Stain with basic fushin.
  3. Cooling of cell = stain gets trapped in between mycolic cell wall and cell.
  4. Acid alcohol wash (harsh):
    - Mycobacteria retain the stain while all other bacteria lose the stain.
  5. Counter color can be used but it will not be taken up by the mycobacteria.
18
Q

Spore Staining

A

Malachite Green Staining
1. Heat up spore to increase permeability.

  1. Add malachite stain.
  2. Cool cells to trap stain.
  3. Alcohol wash removes dye from all cells except for spores.
  4. Counter stain of safranin allows us to figure out which ones are cells (red).
19
Q

Fluorescent staining… the basics.

A

Compound absorbs UV light and emits visible light.

20
Q

Types of fluorescent stains

A
  1. Vital stains:
    - Determines whether something is alive or not
  2. Metabolic stains:
    - Determines whether something is metabolically active or not
21
Q

Types of Conjugated antibodies (for fluo staining)

A
  • Immunofluorescence (discrimination of different bacteria due to the specificity of the antibodies)
22
Q

Vital stains

A

They all target DNA
1. SYTOX green stain diffuses into the nuclear membrane of DEAD cells

  1. DAPI blue stain diffuses into the nuclear membrane of ALL cells

To determine who is alive:
DAPI - SYTOX

23
Q

Metabolic stains

A

CTC targets cells that undergo cellular respiration…

Stain is reduced by succinate dehydrogenase enzyme to a red color.

24
Q

Immunofluorescence

A

Uses antibodies that are conjugated to a fluorochrome that emits visible light when it is excited by UV.

BIO3124 (5 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions