5.5 - Bacterial Cells

Question 1

Shape of a bacillus

Answer 1

A rod

Question 2

Shape of a coccus

Answer 2

A ball

Question 3

Shape of a vibrio

Answer 3

A small curved rod

Question 4

Shape of a spirochete

Answer 4

A long curved rod

Question 5

Shape of a coccobacillus

Answer 5

A “choder,” aka a plump rod

Question 6

What does strepto mean?

Answer 6

Straight chain

Question 7

What does staphylo mean?

Answer 7

Cluster

Question 8

What does diplo mean?

Answer 8

Two

Question 9

What are the minimum requirements for a bacterial cell?

Answer 9

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

Question 10

What are distinguishing features of a Gram Positive envelope?

Answer 10

Techoic acids
Thick layer of peptidoglycan
Plasma Membrane

Question 11

What are distinguishing features of a Gram Negative envelope?

Answer 11

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

Question 12

Features and function of teichoic acids

Answer 12

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

Question 13

What are lipoteichoic acids?

Answer 13

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

Question 14

Features and function of peptidoglycan

Answer 14

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

Question 15

Features and function of the Outer Membrane

Answer 15

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

Question 16

Features of LPS (lipopolysaccharides)

Answer 16

Found in the outer membrane

Made up of O-Antigen and Lipid A

Question 17

Features and function of Lipid A

Answer 17

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

Question 18

What is Gram Negative shock?

Answer 18

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

Question 19

What are porins?

Answer 19

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

Question 20

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

Answer 20

Mycoplasma
Chlamydia
Mycobacterium

Question 21

What are the features of Mycoplasma?

Answer 21

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

Question 22

What are the features of Chlamydia?

Answer 22

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

Question 23

What are the features of Mycobacterium?

Answer 23

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

Question 24

What are mycolic acids?

Answer 24

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

Question 25

Outline the steps of the Gram Staining method

Answer 25

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

Question 26

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

Answer 26

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

Question 27

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

Answer 27

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

Question 28

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

Answer 28

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)

Question 29

What are the four "accessories" of bacteria?

Answer 29

Capsules Endospores Flagella Fimbriae (Pili)

Question 30

What are the properties of a capsule?

Answer 30

Consists of polysaccharides Protects bacteria from dessication and environment Antiphagocytic

Question 31

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

Answer 31

Streptococcus pneumoniae

Question 32

Outline the steps needed to stain a capsule

Answer 32

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

Question 33

What are the properties of endospores?

Answer 33

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

Question 34

What are some examples of bacteria that form endospores?

Answer 34

Bacillus spp. | Clostridium spp.

Question 35

What is the function of Calcium Diplicotinate?

Answer 35

It stabilizes DNA

Question 36

Outline the steps needed to stain an endospore

Answer 36

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

Question 37

What are the properties of flagella?

Answer 37

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

Question 38

What is endoflagella?

Answer 38

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

Question 39

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

Answer 39

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

Question 40

What are the properties of Fimbriae?

Answer 40

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

Question 41

What is the function of sex pili?

Answer 41

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