IV. Outer Membrane Gram Negative Bacteria Only

IV. Outer membrane—Gram negative Bacteria only

A. Gram Negative bacteria have a ______outside their ______

B. Composition is a bit different than cytoplasmic membrane (Figure 4.55):

C. What is LPS

1. Can be divided into parts (Figure 4.56)

a) Lipid portion—fairly standard

b) Polysaccharide portion can be divided into two parts:

ii)

2. LPS is only on the ______leaflet of the OM.

There are only ______on the inner leaflet of the OM

3. LPS is often ______to animals

4. What is the function of LPS?

a) How would you begin to figure this out?

b) LPS is a ______

c) Without LPS bacteria become:

d) LPS also contributes:

D. How does the OM attach to the CM?

1. By:

2. How this is done: Fig. 4.57

E. Q: How do molecules move through the outer membrane? A:

Figure 4.58

1. These are ______that form ______in the OM

2. These are size selective

3. And generally ______except for ______

e.g.:

4. Some are more specific. e. g. LamB

a) Specific for the sugars:

b) Induced by growth on:

c) LamB is also a site for:

5. Other specific ones include:

V. The periplasmic space (Figure 4.55)

A. Space between the:

B. Many proteins are specifically secreted into here. Proteins like:

VI. Extracellular layers and Appendages

A. Pili and Fimbriae

1. Filamentous structure, usually present in multiples copies. FIGURE

A Fimbria is ______than a pilus

2. Similar: FIGURE 4.70

3. Functions:

c) (FIGURE 11.21)

B. S-Layers FIGURE 4.63

1. Cell surface layer composed of:

2. Function is unknown—probably permeability

3. How do we figure this out?

C. Capsules or Glycocalyx and Slime FIGURE 4.59 and 4.60

1. Surface slimy or gummy material.

3. Functions:

a) Attachment of microorganisms to animal cells

c) Resistance to:

VII. FLAGELLUM (Plural = FLAGELLA)

A. What is it?

B. Arrangement varies from organism to organismFIGURE 4.64-4.66

1. Peritrichous—

2. Polar (monotrichous)—

3. Lophotrichous—

C. Structure: FIGURE 4.67 and 11.20

1. Usually single protein:

2. Structure:

3. Flagellar basal body:

a) Parts:

b) Gram-positive species are missing (Fig 4.67B):

c) How does it function:

D. Flagellar swimming requires lots of energy.

1. Drains the:

2. Synthesis of flagellum and swimming requires 50-60 genes

3. Rotation velocity =

Energy cost =

Swimming velocity =

E. Swimming is suppressed when:

F. Because water is a viscous medium to a particle as small as a bacterial cell, what happens when flagellar motor stops?

VII. Moving in a directed way: in E. coli (flagella)

A. It’s a good thing to be able to move towards beneficial stuff (attractants) and away from bad stuff.

B. Cells move with a mixture of motions FIGURE 11.8 Box 11.3

C. ______governs this movement

D. When there is more beneficial stuff, the ratio of these two behaviors changes such that the cells swim more and tumble less

In neutral environmentWith attractant

E. What hands with harmful/repellant compounds?

F. Molecular details of E. coli—FIGURE 11.19 Box 11.3

1. The E. coli cytoplasmic membrane has a system of:

2. Each of these form a complex with two other proteins:

G. How it all happens.

When E. coli swims to: