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50 Cards in this Set

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Define Anabolic Reactions
Link smaller molecules into bigger ones, energy storing reaction, require the input of energy
Define Catabolic Reactions
reactions which break large molecules down into smaller ones, release energy
What is the first law of thermodynamics
Energy is neither created nor destroyed, ie. Initial energy equals final energy.
What is the second law of thermodynamics?
(Entropy) When energy is transformed, disorder in the universe increases.
What is total free energy?
Potential disorder
What are the two ways that a cell can drive a chemical reaction? And what do they need to sustain themselves?
1) By creating disorder inside the cell (digesting a polymer)
2) With a chemical reaction that releases heat and creates disorder in the universe.
These reactions require a constant uptake of energy-rich molecules.
What is the equation for total free energy?
dG = dH-TdS
What happens when dG is negative?
Free energy is released
What happens when dG is positive?
Free energy is required
What are the four types of reactions and their conditions (using the free energy equation)
1) Exergonic, heat is released and S, (entropy or disorder) is increased
2) Heat is released but entropy decreases therefore the reaction is only spontaneous below a certain temperature
3) Heat kept in (H goes up) and entropy increases but it must still be above a certain temperature
4)Heat is kept in and entropy decreases. This is endergonic and will NOT be a spontaneous reaction.
What kind of reactions are anabolic reactions?
They are endergonic
What is chemical equilibrium?
When a reaction A to B and it's reverse, B to A are both taking place at the same rate.What
What is ATP used for?
It's used in cells to capture, transfer and store energy
What is ATP made from?
Adenine nitrogen molecule, Ribose sugar base, and multiple phosphate groups (namely 3)
What is the reaction for ATP?
ATP +H20 -> ADP + Pi(phosphate group) + free energy
Why is the reaction for ATP exergonic?
Because the P-O bond breaking releases more energy than the H-O bond that forms after
How is ADP removed?
Either by hydrolysis or reforming to ATP
What is activation energy?
Energy required to push to exergonic reactions along (put it into some kind of transition state)
What is a catalyst?
A substance that speeds up a reaction but does not actually get used up in the reaction
What are most catalysts made of? (biological catalysts)
proteins, ie enzymes
Does free energy change with catalysts?
No, only the transformation or activation energy
How are exergonic reactions initiated?
By heat, to increase the average kinetic energy of molecules.
How do enzymes work?
Lower the activation energy
What are the three ways that enzymes catalyze reactions?
They orient the substrates correctly, they induce strain on the substrates, or they add charges to the substrates
What are cofactors?
These are usually metal ions or small organic molecules that help the enzymes induce a reaction
What are the principles that govern metabolic pathways?
- Each reaction in the pathway is catalyzed by it's own enzyme
- The operation of each metabolic pathway can be regulated by it's key enzyme
What regulates metabolism?
Inhibitors on enzymes
What happens with irreversible inhibition?
This doesn't allow the enzyme to ever react with the substrate again
How does DIPF (mustard gas) irreversibly inhibit acetylcholinesterase?
It covalently bonds to the active site
What is a competitive inhibitor?
An inhibitor that competes with the substrate for the active site
What is a non competitive inhibitor?
This is an inhibitor that doesn't compete for the active site but instead manages to change the enzyme so that it doesn't accept the substrate
What is another name fore noncompetitive inhibitor?
A Negative allosteric regulator
What is more efficient? Allosteric or competitive inhibition?
Allosteric, it doesn't need to compete with the substrate and is less likely to harm the active site.
What do positive allosteric regulators do?
They activate the enzyme
Describe cooperative allosteric transition. Also, what is the general trend in the rate of allosteric transition with the number of subunits?
Allosteric transition, first has a difficult time binding the inhibitor to the active site, but then this stabilizes the next subunit and so on. With more subunits.the enzyme activation becomes faster.
What metabolic processes are used to breakdown glucose for energy?
- Glycolysis followed by cellular respiration
- Glycolysis followed by fermentation
Define reduction
When hydrogen atoms or electrons are gained
Define oxydation
When electrons or hydrogen atoms are lost
How do you recognize oxydation reactions?
Usually in organic molecules, the number of C-H bonds decreases
What is NAD?
It carries the electrons in cellular redox reactions
What is the reaction for NADH oxidation?
NADH + H+ +1/2O2 -> NAD+ +H20 (0verall)
Oxidation: NADH -> NAD+ +H+ +2e
Reduction: 1/2O2 +2H+ + 2e -> H2O
What is redox potential
The tendency to lose or gain electrons
What are the two stages of glycolysis?
- ATP breaking a sugar to two C3
- Oxidation of a C3 giving NADH + H+ and ATP
What is produced for every glucose in glycolysis?
2 pyruvate
2 NADH + 2H
How do you drive an unfavorable reaction?
Couple them with a favorable one like hydrolysis of ATP
What is the sugar broken down into before entering the second stage of glycolysis?
Glyceraldehyde 3-phosphate
What does the pyruvate after glycolysis do? Where is this reaction catalyzed?
It's oxidixed to acetate and converted to acetyl CoA. Catalyzed in the mitochondrial matrix.
Where does glycolysis take place?
The cytoplasm
Write out the glycolysis reaction.
in notes
Write out the equation for the oxydation of pyruvate
in notes