LEC EXAM #2 CHP. 8 Flashcards
Exergonic reaction:
Releases energy
Reactants > products
Autotroph:
Makes its own food from inorganic source
Heterotroph:
Gets food from organic material
Chemoautotroph:
Makes its own food from a chemical source
LEO goes GER:
Loss of electrons: oxidation
Gain of electrons: reduction
Electron carriers:
NAD+/NADH and FAD/FADH2
Metabolism is made up of:
Anabolism: building up
Catabolism: breaking down
Why does ATP have a lot of energy associated with it?
Has 3 phosphates next to each other that have a negative charge (repelling each other) -> breaking off a phosphate releases some energy (exergonic rx)
Release of phosphate from ATP causes:
Coupling of energonic reactions (reactions that require energy)
Enzymes/biological catalysts make the energy of activation hill:
SMALLER and makes it more likely that the reaction will make place
Product formation:
Does NOT form faster with the enzyme
Rate of the reaction with or without the enzyme:
Stays the same, the enzyme just makes it more likely that the reaction will occur
Energonic reaction:
Requires energy
Products > reactants
Apoenzyme:
Holoenzyme:
- Not active until it binds a coenzyme (vitamin) or cofactor (inorganic ion)
- Has cofactor and coenzyme
Cofactor:
Coenzyme:
Inorganic ion
Vitamin
Enzyme:
- comes from proteins
- lower activation energy
- works like a lock and key
- only binds a specific substrate
- biological catalyst
Substrate:
- Molecule that enzyme acts on
- Fits into an a specific shape of the active site of an enzyme
Process of enzyme reaction:
- Substrate enters active site of enzyme
- Enzyme/substrate complex forms
- Substrate is converted to products (cofactor or coenzymes)
- Products leave the enzyme
Allosteric site:
Other site that causes confirmation change
Non-competitive inhibiton:
Doesn’t directly compete for active site-> binds to allosteric site instead-> causes confirmation change that doesn’t allow you to bind substrate (turns off enzyme)
2 ways to turn off an enzyme:
- Competitive inhibition
- Noncompetitive inhibition
- Cofactors or coenzymes not being present
Allosteric activators:
Activates the enzyme/changes the shape so the substrate can bind again
Allosteric inhibitors:
Binds to enzyme to make it inactive
Feedback inhibition:
The final product of the metabolic pathway that inhibits the pathway by preventing the enzyme from converting the product
True or false:
Prokaryotic and eukaryotic cells both perform glycolysis in the cytoplasm:
True
Enzymes come from:
Proteins that come from genes
Gene:
Piece of DNA that codes for a protein
How do you control whether a competitive inhibitor binds or doesn’t bind to the active site?
Decreasing the inhibitors or substrate
Every cell does:
Glycolysis
-Bacteria, prokaryotic, eukaryotic, e.coli
Noncompetitive inhibition vs. feedback inhibition:
Product MUST be the noncompetitive inhibitor in feedback inhibition but in noncompetitive inhibition, the inhibitor doesn’t have to be the product
Glucose has:
6 carbons-> breaks down into 2, 3 carbon molecules
How many pyruvate can I make from 1 glucose molecule?
2 pyruvate
Investment phase of glycolysis:
Process of converting glucose into glyceraldehyde 3-phosphate
-2 ATP-> 2 ADP (costs us 2 ATP)
Pay off phase of glycolysis:
-Process of making 2, 3 carbon pyruvate from glyceraladehyde 3-phosphate
NAD+-> NADH
2 ADP-> 2ATP
Pyruvate can do what in eukaryotic cells?
Cross the mitochondrial membrane
What cannot cross the mitochondrial membrane?
Glyceraldehyde 3-phophate
What do we get back from the pay off phase of glycolysis?
NAD+-> NADH: electron carriers that have energy associated with it
2ADP-> 2ATP: excess energy
Aceytl-coA=
2 carbons each
In Krebs, for every acetyl-coA, we get:
3 NADH
1 FADH2
1 ATP
4 oxaloacetate + 2 acetyl-coA=
6 carbon= citrate
Oxaloacetate:
4 carbon
Goal of Krebs:
To make electron carriers (NAD+/NADH) and to send them to the ETC
Aerobic prokaryotic cells in glycolysis:
- With oxygen
- Same steps take place but happens in the cytoplasm
Eukaryotes:
Always in mitochondria
Prokaryotes:
Always in cytoplasm and doesn’t cross mitochondrial membrane
Inner membrane of mitochondria:
Outer membrane of mitochondria:
Matrix
Inner membrane space
ETC:
Series of electron carrying proteins
As NADH-> NAD+ and drops off an electron into the matrix:
It pumps out a proton into the inner membrane space
Result of protons in the inner membrane space:
3H+ in inner membrane space
Last pump:
Gives electron to oxygen to make water
Oxygen in the ETC is:
Last electron accepter
ATP synthase:
Tunnel protons go through in the ETC
How is ATP made in the ETC?
Uses the energy of the protons in the inner membrane space to go down their concentration gradient through ATP synthase to take ADP + an inorganic phosphate to make ATP
IN THE ETC:
FADH2 yields:
NADH yields:
2 ATP
3 ATP
Why does FADH2 give you less ATP?
Because it’s dropping off it’s electron at the 2nd pump
NADH-> NAD+ drops off it’s electron at:
First pump
In aerobic prokaryote:
ETC happens in the plasma membrane
In aerobic prokaryotes, protons are pumped:
Outside the cell into plasma membrane-> protons come down ATP synthase into the cytoplasm
Anaerobic prokaryotes:
Can still perform ETC but do NOT have oxygen as their last electron carrier
If no O2 is present:
- Won’t be able to regenerate NAD+
- Fermentation occurs
Goal of fermentation:
-To take NADH-> NAD+ so that you can continue to do glycolysis-> NET 2 ATP
How do humans make ATP anaerobically?
Pyruvate-> (NADH->NAD+)-> lactic acid-> 2 ATP
Yeast makes:
Humans make:
Goal?
Ethanol
Lactic acid
To make NAD+ to continue to run glycolysis to yield 2 ATP
Competitive inhibitor:
Competing for the active site
Krebs occurs where for?
Prokaryotes:
Eukaryotes:
Cytoplasm
Mitochondria
