Microbial Structure & Motility

Question 1

Major functions of the PM in Bacteria?

Answer 1

• Permeability barrier
• Energy conservation
• Acts as anchor for proteins.

Question 2

Structure of cell membrane in (EU)bacteria

Answer 2

Phospholipid bilayer

No cholesterol

Question 3

Cell membrane in Archaea Bacteria

Answer 3

Mix of lipid monolayer and bilayer. Phytanyl chains substitutes for fatty acids.

Question 4

What is the cell wall in bacteria made of?

Answer 4

Murein (peptidoglycan layer)

Question 5

How is the cell wall modified?

Answer 5

• Opening made in cell wall by autolysins
• Bactoprenol adds new material to opening
• Transglycosylases links compound together

Question 6

How do gram-negative bacteria differ?

Answer 6

Peptidoglycan layer is within the membrane. It is thin.

Question 7

Which structure helps bacteria ‘swim’?

Answer 7

Flagella

Question 8

Can flagella be seen through a light microscope?

Answer 8

No, staining is required.

Question 9

What is taxis?

Answer 9

Directed movement in response to stimuli

Question 10

What is run and tumble?

Answer 10

Method that flagella use to move.

Question 11

How does a bacterium respond to stimuli?

Answer 11

Receptor sends signal to flagellum motor for it to initiate movement.

Question 12

What other component of the bacterial cell control motility?

Answer 12

Fimbriae and Pili

Question 13

Which structure is longer; Fimbriae or Pili?

Answer 13

Pili

Question 14

Function of Fimbriae

Answer 14

Adhesion

Question 15

Function of Pili

Answer 15

Genetic exchange

Question 16

What is the slime layer?

Answer 16

Gel-like substances surrounding the cell wall. Made of psac

Question 17

What is the capsule and glycocalyx made of?

Answer 17

• Capsule is made of psac and ppeptide

- Glycocalyx is made of thin psac and glycoprotein.

Question 18

Function of slime/capsule?

Answer 18

• Protect against dehydration

- Protects from pathogens

Question 19

Function of glycocalyx?

Answer 19

Responsible for attachment

Question 20

Where are endospores found?

Answer 20

In extremophiles

Question 21

What is the role of the cell wall?

Answer 21

• Provide strength to cell

- Protects against mechanical and osmotic stress

Question 22

What keeps the peptidoglycan layer rigid?

Answer 22

Glycosidic bonds ad peptide bonds.

Question 23

What is the role of a transpeptidase?

Answer 23

To make peptide links between acetylmuramic residues.

Question 24

What is difference between the cell wall in EU and Archaea bacteria?

Answer 24

Archaea bacteria is made of Pseudo-murein, NOT peptidoglycan. Difference is there isn’t acetylmuramic acid. It is subbed for acetyltalosaminuronic acid

Question 25

What is peptidoglycan made of?

Answer 25

N-acetylmuramic acid and N-acetylglucosamine