September 9

Question 1

Major Functions of the Cytoplasmic Membrane

Answer 1

1. Permeability Layer
2. Protein anchor
3. Energy Gradient

Question 2

Phenotypic Plasticity

Answer 2

One genotype expresses different phenotypes

Question 3

Types of Cell Membrane Proteins

Answer 3

1. Integral: through membrane, firmly attached, used for transport
2. Peripheral: one portion anchored in membrane, binding sites, cell-to-cell signaling

Question 4

Sterols

Answer 4

Lipids, rigid

stabalize and strengthen

Question 5

Hopanoids

Answer 5

Primarily in bacteria

Rigid, help strengthen

Question 6

Archaean Membranes

Answer 6

Ether linkages in lipids (unlike bacteria which have ester linkages)

Monolayer

Fatty acid tails link

More stable in high temp

Question 7

Bacterial Cell Walls

Answer 7

Complex polysaccharide (peptidoglycan)

Three components:

1. Sugars: NAG and NAM
2. Amino acids: form crossbridges between NAG and NAM subunits
3. Diaminopimelic acid (DAP)

Question 8

Gram Positive Cell Walls

Answer 8

Less complex than G-

Approx. 90% peptidoglycan

Teichoic acids: embedded in cell wall, negative charge, binding and transport Ca+ Mg+

Lipoteichoic acid: anchor cell wall and cell membrane

Question 9

Gram Negative Cell Walls

Answer 9

Approx. 10% peptidoglycan

Outer membrane comprises most of cell wall

Lipopolysaccharide (LPS): composes most of the outer membrane, core polysaccharide

Lipid A: “endotoxin” upon death lipid A separates causes fever, inflammation, shock