8.29.2022. study questions

Question 1

Draw and label a prokaryotic cell and its parts

Question 2

What is the general function of a capsule?

Answer 2

adhesion/attachment

Question 3

What is the difference between a capsule and a slime layer?

Answer 3

Capsule: distinct, gelatinous

Slime layer: diffuse, irregular

Question 4

Relate capsules, slime layers, and biofilms

Answer 4

Capsules and slime layers form biofilms

Question 5

What is a biofilm?
How are they removed?
What role does the sugar coat play?
In what environments do they grow the most?

Answer 5

• A slimy community.
• Physically/mechanically, not chemically.
• Sugar coat helps pathogens hide from immune system and stick to a surface.
• Wet, moist.

Question 6

Why are capsules and slime layers sometimes called a glycocalyx? What does glycocalyx mean?

Answer 6

they are made of sugars
shell of sugars

Question 7

How are capsules related to dental caries?
How do capsules aid biofilm formation?

Answer 7

Some capsules and slime layers allow bacterial cells to stick to certain surfaces, like teeth, rocks, and other bacteria. Once they attach, the cells can grow as a biofilm. When a person ingests table sugar, S. mutans uses that to make a capsule. It sticks to the other bacterial cells on the teeth, other bacteria bind to the sticky layer, and the acids produced by bacteria in dental plaque then damage the tooth surface.

Question 8

How can you determine if a bacterium has a capsule?

Answer 8

through capsule staining, such as gram staining

Question 9

How are capsules important for pathogenesis? What could happen to a cell without a capsule?

Answer 9

adhere to surfaces, avoid
/evade the immune system.

englufed and killed by phagosites

Question 10

Which molecule is unique to domain bacteria and not found in archaea or eukarya?

Answer 10

Peptidoglycan

Question 11

Draw the structure of peptidoglycan

Answer 11

What will happen to a bacterial cell if you weaken the structure of peptidoglycan?

Question 12

What effect does penicillin have on peptidoglycan?

Answer 12

PREVENTATIVE. Penicillin binds to the enzyme that makes the bridge. It stops the bridge from being made.

Question 13

What effect does lysozyme have on peptidoglycan?

Answer 13

Breaks down the wall between NAG and NAM to affect existing bacteria.

Question 14

Which gram cell types have porins and why?

Answer 14

gram negative cells, to permit passage of ____

Question 15

Which molecule is unique to Gram positive cells?

Answer 15

teichoic acids

Question 16

How is the gram-negative cell wall different from the gram-positive cell wall? How are they the same?

Answer 16

Positive:
- simpler
- thick layer of peptidoglycan
- teichoic acids (two types A. membrane B. wall i.e. unattached to membrane)
- things move through the mesh/chain link fence

Negative:
- more complex and dangerous
- thin layer of peptidoglycan
- thick outer membrane
-porins permit passage
-periplasm; lipopolysaccharide (LPS) aka endotoxin (PAMP)

Same:
both PAMPs

Question 17

What is LPS?
Where is LPS found?

Answer 17

• lipopolysaccharide
• in the periplasm of a gram negative cell

Question 18

What is the medical significance of LPS aka endotoxins?

Answer 18

outside layer of G- is LPS, not a phospholipid. LPS is the signal to the body that G- cells have invaded. body can fight small amounts, not large amounts.

Question 19

Why can mycoplasma species not be treated with penicillin?

Answer 19

no cell wall = no peptidoglycan = penicillin has no effect

Question 20

What staining technique is used to stain mycobacteria? Why can’t they stain with gram stain?

Answer 20

acid fast staining. mycobacteria don’t have a cell wall.