Micr 221 Lecture 10

Front 1

What is an essential feature of all prokaryotic cells?

Back 1

The CYTOPLASMIC MEMBRANE (CM)

Front 2

What is the CM made of?

Back 2

LIPIDS AND PROTEINS (integral)

Front 3

What is abundant in eukaryotic CM, but lacking in prokaryotic CM (except Mycoplasm)

Back 3

STEROLS

Front 4

What replaces sterols to moderate fluidity in Prokaryotes?

Back 4

HOPANOIDS

Front 5

What is the function of the CM?

Back 5

- Retains cytoplasm

- Selectively permeable barrier

- Provides a SCAFFOLD

Front 6

What does CM provide a scaffold for?

Back 6

-Complexes involved in respiration and photosynthesis for energy generation and chemotaxis

- Transport systems

- OM and PG synthesis

Front 7

What are the 3 "steps" of ATP via respiration?

Back 7

1) Glucose to pyruvate (for energy and e- source)

2) Pyruvate to CO2 (producing NADH/FADH2, provide e- for ETC)

3) NADH/FADH2 oxidized via ETC

Front 8

What is Substrate Level Phosphorylation?

Back 8

ATP synthesized from ADP by phosphorylation coupled with breakdown of ahigh energy organic substrate

Front 9

What enzymes in the CM allow for electron transport?

Back 9

CYTOCHROMES

Front 10

What process generates ATP without ETC?

Back 10

FERMENTATION

Front 11

When is fermentation used??

Back 11

When theres lots of nutrients and no O2

Front 12

How is ATP synthesized during fermentation?

Back 12

Exclusively by Substrate Level Phosphorylation

Front 13

What happens during Substrate Level Phosphorylation?

Back 13

Enzyme transfers a phosphate group from a substrate molecule to ADP (instead of adding an inorganic Pi to ADP) - Generally called OXIDATIVE PHOSPHORYLATION

Front 14

Are members of the ETC reduced or oxidized?

Back 14

BOTH They are REDUCED by the carrier that precedes it, and oxidized by the carrier that follows it?

Front 15

Flow of e- from NADH/FADH2 into ETC to O2 results in movement of protons into WHERE?

Back 15

The PERIPLASM

Front 16

What do protons in the periplasm generate?

Back 16

- Chemical/electircal difference between cytoplasm and perilasm, Called the PROTON MOTIVE FORCE

Front 17

How does CM compare to periplasm when H+ are pumped out to generate PMF?

Back 17

CM is more alkaline (less H+) and more negative

Front 18

How does the amount of protons pumped out differ under high and low O2 conditions?

Back 18

4 H+ moved out under HIGH O2 conditions

2 H+ moved out under LOW O2 conditions

Front 19

Gain of e- is called

Back 19

REDUCTION

Front 20

Loss of e- is called

Back 20

OXIDATION

Front 21

What physiological processes is PMF important in?

Back 21

1) Oxidative phosphorylation

2) Bacterial Flagella rotation

3) Active transport - moving solute against gradient

Front 22

What complex generates ATP?

Back 22

ATP SYNTHASE

Front 23

Structure of ATP synthase is similar to what structure?

Back 23

FLAGELLAR APPARATUS

Front 24

WHat are the 2 major compoents of ATP synthase?

Back 24

F0 and F1

Front 25

Where is F0 inserted?

Back 25

in the CM

Front 26

Where is F1 located

Back 26

The CYTOPLASM

Front 27

How does ATP synthase work?

Back 27

1) H+ transfer through the F0 causes subunit complex C to rotate relative to a/b subunits

2) this causes a conformational change in alpha-beta part (in F1 unit)

3) This activates the catalytic domain to release ATP into the cytoplasm

Front 28

Where is ATP synthase located?

Back 28

Mitochonrial and bacterial/archaeal membranes

Front 29

What is simple diffusion?

Back 29

- molecules move from area of high concentration to low

- NO ENERGY OR CARRIERS/CHANNELS INVOLVED

Front 30

What is transported by simple diffusion?

Back 30

Water and gases

Front 31

What is facilitated diffusion

Back 31

Substances move down a concentration gradient

NO ENERGY, but have carrier proteins/channels involved

SUBStRATE SPECIFIC

Front 32

What is Active transport?

Back 32

Substrate concentration can be HIGHER inside than outsside the cell

Requires ENERGY

Front 33

What are the 3 types of active transport?

Back 33

1) Primary

2) secondary

3) Group translocation

Front 34

Primary active transport:

Back 34

Involves a carrier, requires some ATP hydrolysis to provide energy

Front 35

Secondary active transport

Back 35

involves cotransporters (symports or antiports) and a gradient to move 2 things into the cell at the same time

ex. lactose is moved this way

Front 36

Group translocation:

Back 36

Involves chemical modification of substrate as it enters the cell

Front 37

What is the best studied group translocation system?

Back 37

PTS (Phosphotransferase system)- Sugars are PHOSPHORYLATED as they are brought into the cell

Front 38

What is the phosphaet source in PTS?

Back 38

Phosphophenlpyruvate

Front 39

What is the advantage of group translocation?

Back 39

Will NOT build a gradient against itself (the molecule being moved in) - chemical modification means that the molecule on the outside will be different than that on the inside

Front 40

Macromolecules are generally too large to be brought into a cell (even though good carbon source). How are they transferred across the CM?

Back 40

Must be DEGRADED BY EXTRACELLULAR ENZYMES (into smaller tranposrtable units)

Front 41

What are examples of some extracellular enzymes?

Back 41

Amylase (starch)

Cellulase (cellulose)

Front 42

Can bacteria transport large molecules out of the cell?

Back 42

YES

Front 43

Can they assemble large molecules on the cell surface?

Back 43

YES

Front 44

What do they require for secretion and assembly of large molecules outside of the cell?

Back 44

PROKARYOTIC PROTEIN SECRETION SYSTEMS (next lecture)