The Cell Membrane

Question 1

WHat is the microbial size range?

Answer 1

0.2 - 750 micrometers

Question 2

Why is it beneficial for microorganisms to be so small?

Answer 2

smaller cells have a better surface to volume ratio, the smaller the volume, the lower the nutritive and energy requirements and the easier to survive

Question 3

Which bacterial cell shape has the most variation?

Answer 3

Coccus

Question 4

What is diplococci?

Answer 4

2 cocci in a pair

Question 5

What are tetrads?

Answer 5

4 cocci

Question 6

what are sarcina?

Answer 6

8 cocci, in a cuboidal shape

Question 7

what are streptococci?

Answer 7

cocci strung in a chain

Question 8

What are staphylococci?

Answer 8

a grapelike cluster of cocci

Question 9

What is diplo bacilli?

Answer 9

two connected rods

Question 10

what is strepto bacilli?

Answer 10

chains of rods

Question 11

What two bacterial shapes are most medically relevant?

Answer 11

cocci and bacilli

Question 12

What is the cell envelope?

Answer 12

cell membrane and cell wall

Question 13

Gram + bacteria have a ________ wall of peptidoglycan

Answer 13

thick

Question 14

Gram - bacteria have a _________ wall of peptidoglycan and include a _______

Answer 14

thin, cell membrane

Question 15

What is the phospholipid bilayer composed of?

Answer 15

two fatty acid chains, esther linked to glycerol and phosphate molecules with a side chain (typically ethanolamine or choline)

Question 16

what are integral membrane proteins?

Answer 16

proteins that are embedded in the cell membrane

Question 17

what are peripheral membrane proteins?

Answer 17

proteins that are loosely associated with the membrane, can be internal or external

Question 18

What are the 5 different functions of proteins?

Answer 18

structural support
detection of environmental signals
secretion of virulence factors and communication signals
ion transport
energy storage

Question 19

What is the main difference between cell membranes of prokaryotes and eukaryotes?

Answer 19

eukaryotes utilize cholesterol for stability, while prokaryotes use hopanoids.

Question 20

Do archaea have fatty acids?

Answer 20

no

Question 21

What do archaea have in place of fatty acids?

Answer 21

phytanyl, 4 isoprenes linked together

Question 22

How are phytanyls linked to the phosphoryl head group?

Answer 22

ether linkage

Question 23

Why do archaea use ether linkages as opposed to ester linkages?

Answer 23

ether linkages are stronger and more stable in extreme conditions

Question 24

What is the function of the monolayer biphytanyl in some archaea

Answer 24

adds stability in extreme environments, especially heat

Question 25

What are three cell membrane functions?

Answer 25

protein anchor, energy conservation, permeability barrier

Question 26

what are four properties of active transport

Answer 26

uses energy from ATP (primary) or ion gradients (secondary), show a saturation effect, highly specific, regulated

Question 27

What is symporter transport?

Answer 27

as protons come in to the cell, provides enough energy to pull solute into the cell

Question 28

what is antiporter transport?

Answer 28

as protons come in to the cell, solutes can exit the cell

Question 29

WHat happens in ABC transport?

Answer 29

solute binding protein binds to a solute, then binds to the transporter, which triggers ATP hydrolysis to provide enough energy for solute to enter the cell