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Microbiology And Immunology > Structure Unique To Bacteria > Flashcards

Flashcards in Structure Unique To Bacteria Deck (30)
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1
Q

What is the cell wall of bacteria made from

A

Peptidoglycans (glycan polymers)

Muramic acid and n acetyl glucosamine linked with peptide cross bridges via transpeptidase

2
Q

Name 3 ways peptidoglycan cell wall is important

A

1- target from antibiotics like penecillin

2- keeps osmotic pressure stable

3- protection from cell lysis (which happens due to b lactam)

3
Q

Explain the gram +ve cell wall

A

They have large peptidoglycan wall over their single layer membrane

4
Q

What are the anionic polymers called in the cell walls of gram +ve

A

Teichoic acids

5
Q

What are teichoic acids important for in gram +ve

A

Needed for bacteria survival

Also are antigenic so produce an immune response

6
Q

How is the cell wall different in gram negative

A

They have a thin peptidoglycan cell wall embedded between a double cell membrane

7
Q

What is the structure in gram negative which contains both the peptidoglycan cell wall and inner membrane

A

Periplasm

8
Q

What is found on the outer membrane of gram negative

A

Lipopolysaccharide layer with lipid A and polysaccharides

9
Q

What is lipid A on the outer membrane for in gram negative

A

It produces pyrogenic toxins which cause a fever in infected cells

10
Q

How is the lipopolysaccharide layer important in gram negative defence mechanism

A

They can shed and add a new one which is unrecognised by our immune system

11
Q

What is a crystalline protein lattice called on the outer layer of all bacteria and archaea

A

Proteinaceous s layer

12
Q

What is the proteinaceous s layer for

A

It acts as a selective sieve for protection

13
Q

What is the capsule made of and how is it attached to the cell wall

A

It’s a polysaccharide which is covalently attached to the cell wall peptidoglycan

14
Q

Why is the capsule important to bacteria

A

It helps defend immune system in phagocytosis

15
Q

Is the capsule immunogenic (forms immune response like teichoic acids)

A

Yes sometimes it is

16
Q

What are the appendages called on bacteria used for attachment and adhesion

A

Pili and fimbriae

17
Q

What is pili and fimbriae made from

A

Protein polymers

18
Q

What process is pili and fimbriae needed for

A

Pathogenesis (adhesion to cells to stop being washed away)

And cell conjugation (sex pili)

19
Q

What kind of movement does pili and fimbriae facilitate

A

Twitches

20
Q

Which structure is needed for rotary movement especially in chemotaxis where it changes direction

A

Flagella

21
Q

What happens flagella rotation

A

H+ flow into mot proteins embedded in the inner membrane of gram negative

22
Q

Which rings are rotated on flagella due to mot proteins and H flow

A

The C and MS ring

23
Q

Are pili and Fimbriae also immunogenic like the capsule

A

Yes we detect them

24
Q

What are endospores needed for

A

Cellular survival in bad conditions eg resistant to heat

25
Q

What do spores get engulfed by in sporulation

A

Vegetative cells which are in harsh conditions

26
Q

What happens in sporulation

A

Vegetative cells engulf spores and start to asymmetrically divide and then release the spore in germination

27
Q

What are biofilms and which other structure helps build them

A

Communities of motile cells helped produced by capsule

28
Q

What happens in biofilm development

A

Motile cells attach to surfaces which become SESSILE

These then cluster into a matrix made of polysaccharides, proteins and nucleus acids

The matrix biofilm starts growing

The cells can then disperse due to a trigger

29
Q

What are biofilms for

A

Adhesion

And resistance to antibiotics

30
Q

Give an example of a biofilm

A

Plaque build up