Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
44 Cards in this Set
- Front
- Back
What is an essential feature of all prokaryotic cells? |
The CYTOPLASMIC MEMBRANE (CM) |
|
What is the CM made of? |
LIPIDS AND PROTEINS (integral) |
|
What is abundant in eukaryotic CM, but lacking in prokaryotic CM (except Mycoplasm) |
STEROLS |
|
What replaces sterols to moderate fluidity in Prokaryotes? |
HOPANOIDS |
|
What is the function of the CM? |
- Retains cytoplasm - Selectively permeable barrier - Provides a SCAFFOLD |
|
What does CM provide a scaffold for? |
-Complexes involved in respiration and photosynthesis for energy generation and chemotaxis - Transport systems - OM and PG synthesis |
|
What are the 3 "steps" of ATP via respiration? |
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 |
|
What is Substrate Level Phosphorylation? |
ATP synthesized from ADP by phosphorylation coupled with breakdown of ahigh energy organic substrate |
|
What enzymes in the CM allow for electron transport? |
CYTOCHROMES |
|
What process generates ATP without ETC? |
FERMENTATION |
|
When is fermentation used?? |
When theres lots of nutrients and no O2 |
|
How is ATP synthesized during fermentation? |
Exclusively by Substrate Level Phosphorylation |
|
What happens during Substrate Level Phosphorylation? |
Enzyme transfers a phosphate group from a substrate molecule to ADP (instead of adding an inorganic Pi to ADP) - Generally called OXIDATIVE PHOSPHORYLATION |
|
Are members of the ETC reduced or oxidized? |
BOTH They are REDUCED by the carrier that precedes it, and oxidized by the carrier that follows it? |
|
Flow of e- from NADH/FADH2 into ETC to O2 results in movement of protons into WHERE? |
The PERIPLASM |
|
What do protons in the periplasm generate? |
- Chemical/electircal difference between cytoplasm and perilasm, Called the PROTON MOTIVE FORCE |
|
How does CM compare to periplasm when H+ are pumped out to generate PMF? |
CM is more alkaline (less H+) and more negative |
|
How does the amount of protons pumped out differ under high and low O2 conditions? |
4 H+ moved out under HIGH O2 conditions 2 H+ moved out under LOW O2 conditions |
|
Gain of e- is called |
REDUCTION |
|
Loss of e- is called |
OXIDATION |
|
What physiological processes is PMF important in? |
1) Oxidative phosphorylation 2) Bacterial Flagella rotation 3) Active transport - moving solute against gradient |
|
What complex generates ATP? |
ATP SYNTHASE |
|
Structure of ATP synthase is similar to what structure? |
FLAGELLAR APPARATUS |
|
WHat are the 2 major compoents of ATP synthase? |
F0 and F1 |
|
Where is F0 inserted? |
in the CM |
|
Where is F1 located |
The CYTOPLASM |
|
How does ATP synthase work? |
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 |
|
Where is ATP synthase located? |
Mitochonrial and bacterial/archaeal membranes |
|
What is simple diffusion? |
- molecules move from area of high concentration to low - NO ENERGY OR CARRIERS/CHANNELS INVOLVED |
|
What is transported by simple diffusion? |
Water and gases |
|
What is facilitated diffusion |
Substances move down a concentration gradient NO ENERGY, but have carrier proteins/channels involved SUBStRATE SPECIFIC |
|
What is Active transport? |
Substrate concentration can be HIGHER inside than outsside the cell Requires ENERGY |
|
What are the 3 types of active transport? |
1) Primary 2) secondary 3) Group translocation |
|
Primary active transport: |
Involves a carrier, requires some ATP hydrolysis to provide energy |
|
Secondary active transport |
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 |
|
Group translocation: |
Involves chemical modification of substrate as it enters the cell |
|
What is the best studied group translocation system? |
PTS (Phosphotransferase system)- Sugars are PHOSPHORYLATED as they are brought into the cell |
|
What is the phosphaet source in PTS? |
Phosphophenlpyruvate |
|
What is the advantage of group translocation? |
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 |
|
Macromolecules are generally too large to be brought into a cell (even though good carbon source). How are they transferred across the CM? |
Must be DEGRADED BY EXTRACELLULAR ENZYMES (into smaller tranposrtable units) |
|
What are examples of some extracellular enzymes? |
Amylase (starch) Cellulase (cellulose) |
|
Can bacteria transport large molecules out of the cell? |
YES |
|
Can they assemble large molecules on the cell surface? |
YES |
|
What do they require for secretion and assembly of large molecules outside of the cell? |
PROKARYOTIC PROTEIN SECRETION SYSTEMS (next lecture) |