Lecture #18: Background To Biochemistry Flashcards
Oxidation- reduction reaction
A^0 + B^0 —-> A^+ + B^+
A^+ = oxidized state, reduced energy
B^+ = reduced state, increase energy
Exergonic/exothermic reation
A + B —> C+D + energy
Endergonic/endothermic reaction
M + N + energy —> O + P
Catalyst
- speeds up a chemical reaction
- without being changed in the process
Enzyme
Most important in biology
protein catalyst
- 3-D shape
- lowers activation energy
Affected by:
- temperature
- pH
Ribosomes
RNA catalyst
Allosteric enzymes
enzyme that changes effectiveness based on changing shape when a molecule binds to it
2 ways that it works (both changes shape of enzyme):
1. Activators
2. Inhibitors
Activators
bind to inactive enzyme to activate it
Inhibitors
bind to active enzyme to inactivate it
Control of chemical reactions
- increase the amount of reactants
- increase the amount of enzyme
- increase the amount of activator for allosteric enzyme
Biochemical pathway
starting molecule –> Intermediate –> Intermediate –> product (used up by cell activity) –> back to starting molecule
- if product inhibits an enzyme = self-regulating process (endproduct inhibition/feedback inhibition)
Co enzymes
Non-proteins, helpers for enzymatic reactions
NAD+
- oxidized form
- less energetic
- electron acceptor
NADH
- reduced form
- more energetic
- electron doner
NAD+ + 2H —> NADH + H+
NAD+ —> NADH = reduction
Create ATP
NADH can donate 2e- to an electron transport chain
e- passed through a chain of molecules (in membrane) - energy from e- is used to pump protons (H+) across the membrane (Build up high conc. of H+)
Then the H+ diffuse back through a coupled channel to create ATP
Oxidative phosphorylation
ADP + free phosphate –> ATP
- endergonic process (uses energy)
Substrate phosphorylation
ADP + strip a phosphate from another molecule –> ATP
- exergonic process (releases energy)
Energy
to maintain order of complex structure (or living organisms), there must be a constant input of energy
If a system is left on its own
Complex –> Simple
More order –> less order
more energetic molecules
–> less energetic molecules
What law of thermodynamics is this?
2nd - law of entropy
- entropy = disorder (measure of disorder)
Photosynthesis
6 CO2 + 6H2O (sunlight)—> C6H12O6 (carbohydrate) + 6 O2
- endergonic process
Cellular respiration
C6H12O6 + 6 O2 —> 6 CO2 + 6 H2O + energy (ATP)
- exergonic process
