BIOL 1107 Lecture 9: Chapter 8 and 9 Lecture Notes (Metabolism and Cell Respiration)
METABOLISM
A. Energy coupling: coupling endergonic and exothermic reactions
a. Source = primarily the phosphate
B. Cell respiration has four components:
a. Glycolysis Pyruvate processing
b. The citric acid cycle
c. Electron transport and chemiosmosis
C. Q: why is a glucose molecule so reactive?
a. Endergonic reactions built the glucose molecules → they contain more potential
energy stored than their previous reactants.
b. Allows for greater amount of ATP production.
D. NADH and FADH2 are electron carriers
a. Pyruvate processing, glycolysis, and citric acid cycle all change NAD+ to NADH
b. In electron transport chain, both give up electrons.
i. Oxygen is creating a field of attraction for electrons (oxygen = final
electron acceptor
ii. Oxygen’s electronegativity is pulling the electrons from NADH and
FADH2 towards itself
iii. Oxidation-reduction reaction. (oxygen = reduced, NADH = oxidised)
E. Moving an electron into complex 1 because it is bringing energy into complex 1.
a. Complex 1 = a pump that moves hydrogen against its concentration gradient. So
it needs electrons as a source of energy for active transport.
b. Electron then goes through complex II and III and then Oxygen comes in as the
final electron acceptor
c. Oxygen accepting an electron is what causes ATP synthase to start functioning
i. Generated an abundance of ATP molecules
F. Mitochondria creates an environment in the context of the cell where you can increase
the potential energy to generate ATP molecules as a source of energy
G. ATP synthase - contains a channel that allows ions to pass through without any energy
required. Facilitated diffusion
a. Can take the potential energy and convert it into chemical energy.
b. Performs oxidative phosphorylation
H. Covalent bonds in glucose contain electrons that exhort a large amount of potential
energy. When glucose is broken down in cell respiration, the electrons become available
for NAD+ and FAD+
I. If O2 concentrations is too low, respiration will not undergo anything other than
glycolysis.
J. Either lactic acid or ethanol produced
a. For lactic acid (humans): Inflammation presses against sensory neurons that is
perceived as pain
b. Pathway is reversed, which decreases the pain over the next few days.
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