3.7 Cellular Respiration
Cellular respiration is the controlled release of
energy from organic compounds (lipids,
carbohydrates and proteins) in cells
to produce ATP.
3.7 Syllabus Statements
3.7.1 Define ‘Cellular Respiration.
3.7.2 State that, in cell respiration, glucose in the cytoplasm is
broken down by glycolysis into pyruvate, with a small
yield of ATP.
3.7.3 Explain that, during anaerobic cell respiration, pyruvate
can be converted in the cytoplasm into lactate, or ethanol
and carbon dioxide, with no further yield of ATP.
3.7.4 Explain that, during aerobic cell respiration, pyruvate can
be broken down in the mitochondrion into carbon
dioxide & water with a large yield of ATP.
Cellular Respiration (The Basics)
Cellular respiration is the controlled release of energy
from organic compounds (lipids, carbohydrates and
protein) in cells to form ATP.
 Occurs in ALL ORGANISMS (even those organisms
like prokaryotes w/out mitochondria) because all
living cells need a continual supply of energy.
 Cellular respiration is considered a catabolic
reaction and involves a series of very complex
metabolic reactions involving numerous enzymes.
Cellular Respiration Involves a Transformation of
Energy.
The Balanced Equation
Cellular Respiration and Breathing (Respiration)
Cellular Respiration occurs at the cellular
level and is NOT the same thing as breathing.
 Cellular Respiration occurs at the cellular
level (cytoplasm and mitochondrion in
eukaryotes) and inner cell membrane
(prokaryotes).
 Breathing delivers a reactant (oxygen gas)
for cell respiration and removes a waste
product (carbon dioxide).
Where Does Cellular Respiration Occur?
In prokaryotes, however, cell
Respiration occurs in the folds of the
Cell membrane.
A Summary of Aerobic Cell Respiration
In aerobic
cell
respiration,
approx.
36-38 ATP
are
produced per
glucose
Molecule.
The Use of Glucose in Cell Respiration
 Glucose is often the organic compound used in cell respiration.
Chemical reactions in the cytoplasm break down glucose into a simpler
organic compound called pyruvate. A small amount of ATP is released.
Anaerobic Cell Respiration
 If no oxygen is available, the pyruvate remains in the cytoplasm and is
converted into a waste product that can be removed from the cell. No
ATP is produced in these reaction. In humans, the waste product
lactate (lactic acid) is produced. In yeast, the products are ethanol
(alcohol) and carbon dioxide.
Aerobic Cell Respiration
 If oxygen is available, the pyruvate enters the mitochondrion. Inside
the mitochondrion, the pyruvate is broken down into carbon dioxide
and water. A large amount of ATP (36-38 ATP molecules) are produced
from one glucose molecule. Aerobic cell respiration has a higher yield
(per gram of glucose) than anaerobic cell respiration.
SUMMARY
Comparing Photosynthesis and Cellular Respiration
Interpreting Graphs