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Flashcards in 5.5 - Bacterial Cells Deck (41)
1

Shape of a bacillus

A rod

2

Shape of a coccus

A ball

3

Shape of a vibrio

A small curved rod

4

Shape of a spirochete

A long curved rod

5

Shape of a coccobacillus

A "choder," aka a plump rod

6

What does strepto mean?

Straight chain

7

What does staphylo mean?

Cluster

8

What does diplo mean?

Two

9

What are the minimum requirements for a bacterial cell?

1) Nucleoid
2) Ribosome
3) Cytoplasm
4) Cytoplasmic Membrane

10

What are distinguishing features of a Gram Positive envelope?

Techoic acids
Thick layer of peptidoglycan
Plasma Membrane

11

What are distinguishing features of a Gram Negative envelope?

Outer Membrane containing LPS and porins
Thin layer of peptidoglycan
Periplasmic space
Plasma Membrane

12

Features and function of teichoic acids

Glycerol phosphate polymers
Ribitol phosphate polymers
Create stability and a negative charge

13

What are lipoteichoic acids?

Teichoic acids that stretch from the cell wall to the plasma membrane

14

Features and function of peptidoglycan

Also called "cell wall" or "murein"
Made up of a NAM-NAG disaccharide
Crosslinked with Amino Acids
Creates stability and shape

15

Features and function of the Outer Membrane

Only found on Gram Negative envelopes
Super hydrophilic permeability barrier
Major factor in resistance

16

Features of LPS (lipopolysaccharides)

Found in the outer membrane
Made up of O-Antigen and Lipid A

17

Features and function of Lipid A

Heat stable
Low concentrations are good for the immune system
High concentrations activate complement system
High concentrations are toxic and induce endotoxic shock

18

What is Gram Negative shock?

Also called endotoxic shock or septic shock, it is the result of abnormally high concentrations of Lipid A in the body

19

What are porins?

Pores found on the Outer Membrane that allow hydrophilic molecules into the bacterial cell

20

What are three of the "special" types of bacteria?

Mycoplasma
Chlamydia
Mycobacterium

21

What are the features of Mycoplasma?

"Pleomorphic" (No cell wall)
Contains sterols in cell membrane
Found in the GU tract
Resistant to penicillin and cephalosporins
One of the smallest prokaryotes

22

What are the features of Chlamydia?

Very thin cell wall, so thin most people say it isn't present
Susceptible to penicillin
Gram negative under stain
Obligate intracellular bacteria
Cannot synthesize ATP

23

What are the features of Mycobacterium?

Acid-fast
Contains an outer layer of mycolic acids that are hydrophobic
Resistant to drying and disinfectants
Mycolic acids act as MAMPs for the immune system

24

What are mycolic acids?

Fatty acids found on the outside of Mycobacterium that act as MAMPs for the immune system. These fatty acids are extremely hydrophobic, contributing to a waxy layer around the cell that does not allow many things in

25

Outline the steps of the Gram Staining method

Fixation -> Crystal Violet -> Iodine -> Decolorization -> Counterstain with Safranin

26

What colors are associated with each step of the gram staining method?

Fixation (Both Clear)
Crystal Violet (Both purple)
Iodine (Both purple)
Decolorization (Gr+ purple, Gr clear)
Couterstain with Safranin (Gr+ purple, Gr- pink)

27

Outline the steps of the Ziehl-Neelsen acid-fast staining method

Carbol Fuchsin -> Acid Alcohol Decolorizer -> Counterstain Malachite Green or Methylene Blue

28

What colors are associated with each step of the acid-fast staining method?

Carbol Fuchsin (Both pink)
Acid Alcohol Decolorizer (AF pink, Non acid-fast clear)
Counterstain Malachite Green or Methylene Blue (AF pink, Non acid fast blue)

29

What are the four "accessories" of bacteria?

Capsules
Endospores
Flagella
Fimbriae (Pili)

30

What are the properties of a capsule?

Consists of polysaccharides
Protects bacteria from dessication and environment
Antiphagocytic

31

What is an example of a bacterium with a very large capsule?

Streptococcus pneumoniae

32

Outline the steps needed to stain a capsule

Negatively charged bacteria -> Acidic dyes repel negative ions -> Background stain is used -> Stain cells w/ simple stain

33

What are the properties of endospores?

Found on some Gram Positive rods
Dormant
Extremely resistant
Contains Calcium Diplicotinate in its core
Location is species dependent

34

What are some examples of bacteria that form endospores?

Bacillus spp.
Clostridium spp.

35

What is the function of Calcium Diplicotinate?

It stabilizes DNA

36

Outline the steps needed to stain an endospore

Fixed smear flooded w/ Malachite green -> Heated for 5 minutes -> Washed -> Counterstained w/ safranin

37

What are the properties of flagella?

Made up of protein
Amino Acid sequence in each one varies
Moves using chemotaxis

38

What is endoflagella?

Axial filaments within an envelope that aid in movement
They are found in spirochetes

39

How are flagella able to be seen under a viewing medium?

They are thickened using multiple coats of mordant that contain tannic acid or potassium alum

40

What are the properties of Fimbriae?

Also called Pili
Attach to cells via adhesins
Contain the protein pilin as a subunit

41

What is the function of sex pili?

Sex pili are used to exchange genetic information from cell to cell. These are longer than normal pili.