5.5 - Bacterial Cells Flashcards

1
Q

Shape of a bacillus

A

A rod

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2
Q

Shape of a coccus

A

A ball

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3
Q

Shape of a vibrio

A

A small curved rod

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4
Q

Shape of a spirochete

A

A long curved rod

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5
Q

Shape of a coccobacillus

A

A “choder,” aka a plump rod

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6
Q

What does strepto mean?

A

Straight chain

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7
Q

What does staphylo mean?

A

Cluster

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8
Q

What does diplo mean?

A

Two

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9
Q

What are the minimum requirements for a bacterial cell?

A

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

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10
Q

What are distinguishing features of a Gram Positive envelope?

A

Techoic acids
Thick layer of peptidoglycan
Plasma Membrane

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11
Q

What are distinguishing features of a Gram Negative envelope?

A

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

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12
Q

Features and function of teichoic acids

A

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

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13
Q

What are lipoteichoic acids?

A

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

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14
Q

Features and function of peptidoglycan

A

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

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15
Q

Features and function of the Outer Membrane

A

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

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16
Q

Features of LPS (lipopolysaccharides)

A

Found in the outer membrane

Made up of O-Antigen and Lipid A

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17
Q

Features and function of Lipid A

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
Q

What is Gram Negative shock?

A

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

19
Q

What are porins?

A

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

20
Q

What are three of the “special” types of bacteria?

A

Mycoplasma
Chlamydia
Mycobacterium

21
Q

What are the features of Mycoplasma?

A
"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
Q

What are the features of Chlamydia?

A
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
Q

What are the features of Mycobacterium?

A

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
Q

What are mycolic acids?

A

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
Q

Outline the steps of the Gram Staining method

A

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

26
Q

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

A
Fixation (Both Clear)
Crystal Violet (Both purple)
Iodine (Both purple)
Decolorization (Gr+ purple, Gr  clear)
Couterstain with Safranin (Gr+ purple, Gr- pink)
27
Q

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

A

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

28
Q

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

A

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
Q

What are the four “accessories” of bacteria?

A

Capsules
Endospores
Flagella
Fimbriae (Pili)

30
Q

What are the properties of a capsule?

A

Consists of polysaccharides
Protects bacteria from dessication and environment
Antiphagocytic

31
Q

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

A

Streptococcus pneumoniae

32
Q

Outline the steps needed to stain a capsule

A

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

33
Q

What are the properties of endospores?

A
Found on some Gram Positive rods
Dormant
Extremely resistant
Contains Calcium Diplicotinate in its core
Location is species dependent
34
Q

What are some examples of bacteria that form endospores?

A

Bacillus spp.

Clostridium spp.

35
Q

What is the function of Calcium Diplicotinate?

A

It stabilizes DNA

36
Q

Outline the steps needed to stain an endospore

A

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

37
Q

What are the properties of flagella?

A

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

38
Q

What is endoflagella?

A

Axial filaments within an envelope that aid in movement

They are found in spirochetes

39
Q

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

A

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

40
Q

What are the properties of Fimbriae?

A

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

41
Q

What is the function of sex pili?

A

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