Fimbriae (pili) and Cell Walls

Question 1

What are Fimbriae (or pili)

Answer 1

Appendages that are short, thin & fibrous

Question 2

Where are Fimbriae (pili) found?

Answer 2

On almost all Gram (-) Bacteria and
on some Gram (+) Bacteria

Question 3

What is the function of Fimbriae or pili?

Answer 3

Adhesion to surfaces, other bacteria, and host cells

Question 4

Some pili are used for a special type of motility called what?

Answer 4

Twitching motility

Question 5

What are sex pili used for?

Answer 5

Cell to cell conjugation

Question 6

What is conjugation?

Answer 6

Transferring DNA to another bacterial cell

Question 7

What form is DNA usually in when transferred by conjugation?

Answer 7

Plasmid

Question 8

What are the three functions of the cell wall?

Answer 8

Protect from osmotic lysis
Protection from physical insults/ trauma
Maintain shape

Question 9

What is a bacterial cell wall composed of?

Answer 9

Peptidoglycans

Question 10

What is the structure of peptidoglycan?

Answer 10

Carbohydrate backbone with peptide cross bridges and side chains

Question 11

Which bacterial cell walls are thick and consist of multiple layers of peptidoglycan?

Answer 11

Gram Positive

Question 12

Which cell walls contain Teichoic acids?

Answer 12

Gram Positive bacteria

Question 13

Which cell walls have a thin (sometimes only one layer) peptidoglycan layer?

Answer 13

Gram Negative

Question 14

Which cells have an outer membrane external to the cell wall that protects the cell from immune cells and damaging chemicals?

Answer 14

Gram Negative bacterial cells

Question 15

What are the components of the outer membrane of gram negative cells?

Answer 15

Lipopolysaccharide (sugars = antigens & lipids= endotoxins)

Question 16

What does the outer membrane of a gram negative cell have that allows small molecules to move across ?

Answer 16

Porins