Bacterial Structures & Functions

Question 1

Staphylococcus, Streptococcus & Bacillus are Gram ___

Answer 1

+

Question 2

E. Coli and several spirochetes are Gram ____

Answer 2

-

Question 3

bacteria name with sphere shape

Answer 3

coccus/cocci

Question 4

bacteria with stick or rod shape

Answer 4

bacillus/bacilli

Question 5

bacteria with spiral long hair shape

Answer 5

spirochete/s

Question 6

staphylo-

Answer 6

cluster

Question 7

strepto-

Answer 7

string or chain

Question 8

diplo-

Answer 8

double

Question 9

Example of Staphylobacilli

Answer 9

Staphylobacilli bacteria do not exist

Question 10

Anatomy of a bacterial cell

Answer 10

• plasma membrane
• cell wall
• capsule
• pilus
• flagellum

note: a bacteria will have a plasma membrane; composition or presence of cell wall varies; bacteria may or may not have capsule/pilus/flagellum

Question 11

bacteria cell envelope

Answer 11

includes everything that s tethered to the bacteria cell from the cell membrane outwards

• cell membrane (inner plasma membrane)
• peptidoglycan layer
• outer membrane (for Gram -)

Question 12

Is the extracellular polysaccharide capsule a part of the bacterial cell envelope?

Answer 12

No

Question 13

Gram + stains

Answer 13

purple

Question 14

Gram - stains

Answer 14

pink/red

Question 15

The only type of bacteria that does not have peptidoglycan

Answer 15

mycoplasma

Question 16

bacteria cell wall contains

Answer 16

everything beyond the plasma membrane

Question 17

components of cell wall in Gram - bacteria

Answer 17

• Thin peptidoglycan layer
• outer membrane
  
  • outer leaflet composed of Lipid A
• LPS (embedded in outer membrane)

Question 18

Where is the peptidoglycan layer in Gram - bacteria

Answer 18

between the inner and outer membranes

Question 19

Which group of bacteria have an outer membrane?

Answer 19

unique to Gram - bacteria

Question 20

LPS is unique to

Answer 20

Gram - bacteria

Question 21

What is LPS

Answer 21

• Lipopolysaccharide
• bound to Lipid A
• core sugars +/- repeating O-antigen
• known as an endo-toxin

Question 22

Components of cell wall in Gram + bacteria

Answer 22

thick peptidoglycan later containing LTA (lipoteichoic acid)

Question 23

Mycoplasma spp.

Answer 23

• No cell wall at all (just plasma membrane)

- Pleomorphic (many different shapes)

Question 24

Mycobacterium spp.

Answer 24

-Thick, waxy outer-membrane like surface containing mycolic acid and unusual sugars

Question 25

Mycolic acid is found in

Answer 25

Mycobacterium

Question 26

Does Mycoplasma have peptidoglycan?

Answer 26

No

Question 27

Does Mycobacterium have peptidoglycan?

Answer 27

Yes (recall it has a cell wall)

Question 28

Stain used for Mycobacterium

Answer 28

Acid-fast stain Gram stain doesnt hold because of mycolic acid

Question 29

Capsule

Answer 29

- Gelatinous coverings exterior to the peptidoglycan (G+) or outer membrane (G-) - Composed of polysaccharide - Protect bacteria from phagocytosis

Question 30

Feature of many bacteria that cause pneumonia and/or meningitis

Answer 30

Capsule

Question 31

Pili/fimbriae

Answer 31

- Filamentous appendages - Composed of multiple protein subunits - Mediate attachment to host and bacterial cells - Permit exchange of genetic material between bacterial cells - Twitching motility & biofilm formation - Important feature on many Gram - pathogens

Question 32

Flagellum

Answer 32

- Filamentous appendages, larger in diameter and longer than pili - Can be on G+ and G- - Composed of multiple protein (flagellin, a.k.a. H-antigen) subunits attached to a complex molecular motor - Important for locomotion

Question 33

Which two antigens are described in this strain designation: E. coli O157:H7

Answer 33

Saccharides in LPS: Flagellin

Question 34

Is Lipid A an antigen?

Answer 34

No - it is not recognized because it is not a surface protein/extracellular; it's in the outer membrane of gram - bacteria just under the LPS antigens that stick out from it (the saccharides sticking out from LPS is O-antigen)

Question 35

Examples of encapsulated bacteria

Answer 35

- Streptococcus penumoniae (G+) - Neisseria meningtidis (G-) - Haemophilus influenzae (G-)