Chapter 3

Question 1

Prokaryote Size. Shape, and Arrangement

Answer 1

Shape: 
-cocci and rods
-other
Arrangement:
-determined by plane of division 
- " by separation or not 
Size: 
-varies

Question 2

Cocci (coccus) Shape

Answer 2

Spheres

• diplococci
• streptococci -chains
• staphylococcii - grape like clusters
• tetrads - 4 cocci in a square
• sarcinae - cubic formation of 8 cocci

Question 3

Other Shapes: Bacilli, Virbrios, Spirilla

Answer 3

Bacilli (bacillus) - rods
-coccobacilli - very short rods
Vibrios - comma shaped rods
Spirilla - rigid helices

Question 4

Other Shapes: Spirochetes, Mycelium, Pleomorphic

Answer 4

Spirochetes - flexible helices
Mycelium - long multinucleate filaments
Pleomorphic - variable in shape

Question 5

Size of Prokaryotes

Answer 5

Smallest = 0.3 nm (mycoplasma)
avg rod - 1.1-1.5x 2-6m
v large -600-80m (epulopiscium)

Question 6

Size-Shape relationship

Answer 6

nutrient uptake
S to V ratio S/V
Small size may be protective mechanism from predation

Question 7

Bacterial Cell Organization-Common Features

Answer 7

Cell envelope
(plasma, cell wall, capsule/slime layer)
Cytoplasm
External Structures

Question 8

Bacterial Plasma Membrane

Answer 8

• req

- some w/ internal membrane

Question 9

Function of Plasma Membrane

Answer 9

Encompass cytoplasm 
Selectively permeable 
Interacts w/ external environment 
- receptors -> chemicals in surroundings 
-transport systems 
-metabolic processes

Question 10

Fluid Mosaic Model of Membrane Structure

Answer 10

lipid bilayers with floating proteins

• amphipathic
• > polar ends(hydrophillic) + non polar tails (hydrophobic)
• membrane proteins

Question 11

Peripheral Proteins

Answer 11

loosely connected to membrane

easily removed

Question 12

Integral Proteins

Answer 12

within membrane
carry out impt fxns
maybe as microdomains

Question 13

Bacterial Lipids

Answer 13

saturation levels = enviro conditions (eg. t)

• bacterial membranes lack sterols, contain sterol like molecules, hopanoids
• stabilize membrane
• in petroleum

Question 14

Uptake of nutrients (macro)

Answer 14

• C,O,H,N,P,S,
• > organic molecules (proteins, lipids, carbs, nucleic)
• K, Ca, Mg, Fe
• > cations (enzymes, biosynthesis)
• req in large amounts

Question 15

Uptake of nutrients (micro)

Answer 15

• Mn, Zn, Co, Mo, Ni, Cu
• > trace amounts
• > in water, or media comp.
• > ubiquitous
• > enzymes/cofactors

Question 16

Uptake of nutrients - Growth Factors

Answer 16

Org, compounds

• essential cell components,
• supplied by enviro

Question 17

Classes of growth factors

Answer 17

AA
-protein syn
Purines + Pyrimidines 
-NA+synthesis
Vitamins 
-enzyme cofactors

Question 18

What transport mechanisms do microorganisms use?

Answer 18

Facilitated diffusion,
Active Transport
Group Translocation

Question 19

Passive Diffusion

Answer 19

Higher > lower [] between interior and exterior,

-H20, 02, C02

Question 20

Facilitated Diffusion

Answer 20

not energy dependent 
direction from high to low 
size of [gradient] - rate of uptake 
-channels/ carrier proteins involved (permeases) 
-small [] gradient 
MORE IN EUK, THEN BAC AND ACH

Question 21

Active Transport

Answer 21

Req E, (ATP/proton motive force used)
against gradient (low-high)
carrier proteins

Question 22

ABC Transporters

Answer 22

Primary Active Transporters use ATP
-> transporters
(ALL)
2 binding domains

Question 23

Secondary Active Transport

Answer 23

Major Faciliator Superfamily
ion gradient -> cotransport substances
-> protons,
-> symport - two substances in SAME direction
-> antiport - two substances in OPPOSITE direction

Question 24

Group Translocation

Answer 24

E dep transport- chemically modifies molecule brought into cell
Phosphoenolpyruvate: sugar phosphotransferase system (PTS)

Question 25

Iron Uptake

Answer 25

Ferric - insoluble
Siderophores - aid uptake
-> complex with ferric
–> then transported into cell

Question 26

Peptidoglycan Structure

Answer 26

Long strands
2 sugars: NAG+lactic acid attached by ether linkage, NAM
D+L AA
-crosslinkage

Question 27

Gram-Negative Cell Walls

Answer 27

More complex than +ve
no teichoic acids
enzymes in intermembrane space

Question 28

Lipopolysaccharide (LPS)

Answer 28

• o side chain
• core polysaccharide
• lipid A
• ve charge on cell surface
• stabilize other mem structure
• attatchement to surfaces and biofilm
• permeability barrier
• protection from host defences
• endotoxin