Download Cellular Respiration Lecture Notes

Cellular Respiration
Lecture Notes
I. Introduction
a. ‘Big Picture’ Ideas
i. Energy
1. ATP is the only form of energy that the cell can use
2. Used for cell to do work
ii. Structure/Function
1. Uses energy from catabolic processes to fuel anabolism
b. Important
Molecules
c. Oxidation/Reduction Reactions
i. Loss of electrons for oxidation
ii. Gain of electrons for reduction
d. Phosphorylation Reactions
i. Oxidative phosphorylation
1. 3rd stage of respiration
2. Electrontransport chain accepts electrons from the breakdown of
products during the first 2 stages
3. Passes electrons from one molecule to another
4. electrons combined with hydrogen ions
5. molecular oxygen to form water
6. energy released at each step of the chain is stored in mitochondria to
make ATP
ii. Substrate level
phosphorylation
1. Forms smaller
amount of ATP
2. Enzyme transfer
phosphate group
from substrate to an
ADP (substrate is
organic molecule
generated during
catabolism of
glucose)
e. Review Structure of a
Mitochondrion
II. Glycolysis
a. Big Idea
i. To harvest chemical energy by oxidating glucose --> 2 pyruvate acids + 2 ATP
b. Where Does it occur
i. Cytosol (in cytoplasm)
c. Molecules In
i. Glucose
ii. 2 ADP + 2 P (inorganic
phosphate)
iii. 2 NAD+
d. Molecules Out
i. 2 Pyruvate + 2 H2O
ii. 2 ATP
iii. 2 NADH + 2H+
e. Details to Know
i. 1st Step of breaking down
sugars into 2 pyruvic + 2 ATP
+ 2 NADH
ii. 10 Steps (1st5 = energy
investment, 2nd 5 = energy
payoff)
iii. Anaerobic= no oxygen
required
iv. Releases <1/4 energy stored in
glucose
III. The ‘Intermediate Step’
a. Big Idea
i. Conversion of pyruvate to actyl CoA
b. Where Does it occur
i. Pyruvate enters mitochondion from ctyosol via transport protein
c. Molecules In
i. CO2, NADH, H+, Acetyl CoA
d. Molecules Out
i. Pyruvate, NAD+, Coenzyme A
e. Details to Know
i. Acetyl CoA is necessary to begin Krebs cycle
IV. The Krebs Cycle
a. Big Idea
i. enzymes complete the oxidation of organic fuel to energy with presence of
molecular oxygen
b. Where Does it occur
i. Mitochondrion
c. Molecules In
i. Acetyl CoA, 3 NAD+, FAD, ADP, + Pi (inorganic phosphate)
d. Molecules Out
i. 2 CO2, 3 NADH, 3 H+, ATP, FADH2
e. Details to Know
f. 8 Steps with a specific enzyme for each step
g. Oxidizes organic fuel derived from pyruvate
h. 1 ATP released per turn
i. Most energy is transferred to NAD+ and FAD
j. Energy then goes to electron transport chain to synthesize ATP by oxidative
phosphorylation
V. The Electron Transport Chain
a. Big Idea
i. NADH → protiens → drive H+ out of Mitochondrial matrix → let H+ flow
through ATP Synthase to make ADP + Pi → ATP
b. Where Does it occur
i. Mitochondrial matrix, membrane, and intermembrane space
c. Molecules In
i. NADH & H+ & O2
ii. ADP + Pi
d. Molecules Out
i. H2O ATP
e. Details to Know
i. Chemiosmosis – ATP synthesis powered by the flow of H+ back across the
membrane (Oxidative phosphorylation)
ii. Cytochromes (cyt) – protein electron carriers w/ prosthetic group (heme group)
iii. Heme group – 4 organic rings surrounding central iron; similar to hemoglobin
but carries electrons, not oxygen
iv. ATP Syhtnase – enzyme that makes ATP from ADP & inorganic phosphate
1. Rotor – spins clockwise when H+ flows past it down the conc. Gradient
2. Stator – holds knob stationary, anchored to membrane
3. Rod – also spins, activates catalytic sites in knob
4. Knob – catalytic sites join Pi + ADP → ATP
v. Proton-motive force – H+ gradient across membrane
VI. Review Respiration Products & Reactants
VII.
Fermentation
a. Big Idea
i. Glycolysis + recycling of NADH → NAD+ by transferring electrons to pyruvate
or derivatives
b. Where Does it occur
c. Molecules In
i. Alcohol Fermentation
1.
2. Glucose + 2 H+ + 2 NADH
ii. Lactic Acid Fermentation
1.
2. Glucose + 2 H+ + 2 NADH
d. Molecules Out
i. 2 NAD+ + 2 Lactate/2 Ethanol
e. Details to Know
i. Less efficient that respiration
ii. Evolutionarily 1st
iii. Anaerobic (no oxygen)
VIII.
Control of Respiration
I. Catabolic Pathways