Download Cellular respiration

Breathing (Pulmonary Respiration)
versus Cellular Respiration
Cellular Respiration
General Equation:
C6H12O6 + 6O2  6CO2 + 6H2O + ~38 ATP
Glucose + Oxygen  Carbon Dioxide + Water + Energy
Cellular respiration is how all
eukaryotic cells gain energy, in the form
of ATP, from macromolecules, such as
glucose (sugar).
Types of Respiration
•Aerobic Respiration – cellular
respiration using oxygen (O2).
•Anaerobic Respiration (Fermentation)
– cellular respiration in the absence of
O2.
•There are 2 types of Anaerobic
Respiration – Lactic Acid Fermentation
and Alcoholic Fermentation.
REDOX reactions: A series of reactions where
molecules are reduced then oxidized or vice-versa,
resulting in the transfer of energy.
Reduction: When a molecule gains an electron (e-)
thereby reducing its charge (increasing energy).
Oxidation: When a molecule loses an electron (e-)
thereby gaining a charge (decreasing energy).
Which variable (X or Y) is being reduced/oxidized?
X- + Y+  X+ + Y-
Cellular respiration consists of
3.5 steps:
1. Glycolysis (splitting of sugar)
1.5 Prep-Step
2. Krebs Cycle or Citric acid cycle
3. Electron transport chain
Mitochondrial Anatomy
1. Glycolysis
•Occurs in the cytosol of the cell, regardless of
the presence of oxygen (O2)
•Involves the splitting of a glucose (sugar)
molecule into two, 3-carbon molecules
(pyruvate)
•Uses 2 ATP molecules to split glucose but
creates 4 ATP molecules from this splitting.
•Also reduces 2 NAD+ into 2 NADH’s
1.5 Prep-Step
•Occurs in the matrix of the
mitochondria ONLY if oxygen (O2) is
present in the mitochondrion.
•Converts the 2 pyruvates (from
glycolysis) into 2 acetyl-CoA’s
•Generates 2 NADH’s & 2 CO2
2. Krebs Cycle
•Occurs in the matrix of the mitochondrion.
•Turns twice for each glucose broken down in
glycolysis
•Adds acetyl-CoA to a 4-carbon molecule,
which is then oxidized (electrons taken away
from) in multiple steps into 2CO2 per turn (or
4 CO2 per glucose molecule)
•Generates 3 NADH’s, 1 ATP, and 1 FADH2 per
turn
3. Electron Transport Chain
(ETC)
•Occurs in the inner membrane of the
mitochondrion.
•Series of REDOX reactions between
molecules that take electrons from NADH &
FADH2 and passes them to the FINAL
ELECTRON ACCEPTOR (OXYGEN!!!)
•When oxygen receives these electrons it
becomes H2O
•Electrons that travel through the ETC
generate energy that powers proton pumps.
ETC Continued…
•Proton pumps pump H+ from the matrix
into the intermembrane space (IMS)
which generates a chemiosmotic
gradient of H+ (between the
intermembrane space and the matrix)
•This gradient allows H+ to travel back
(down their gradient) to the matrix
through a membrane protein, ATP
Synthase.
ETC Continued…
•Each NADH that gives ETC electrons
results in the generation of 3 ATP
•Each FADH2 that gives ETC electrons
results in the generation of 2 ATP
•Energy generated (proton motive
force) from H+ traveling down their
gradient is used to power ATP
Synthase to create ATP.
Anaerobic Respiration
Fermentation and Respiration Compared
1.
Both produce ATP from food, cellular respiration is
aerobic while fermentation is anaerobic.
2. Both use glycolysis; have a net production of 2 ATP
by substrate phosphorylation, and both used NAD+
as the oxidizing agent.
3. Respiration yields up to 19 times more ATP per
glucose molecule than fermentation does.
Types of Fermentation
Alcoholic fermentation- pyruvate is
converted to ethanol to regenerate the
supply of NAD+. (Done by yeast)
C6H12O6  2C2H5OH +2CO2 +NAD+
Lactic acid fermentation- pyruvate is
reduced to NADH to form lactate, no
release of CO2.
C6H12O6  2C3H6O3 + NAD+
Diagram of
Both
Biochemical
Pathways
CR vs PS