Cellular respiration is the controlled release of energy from organic compounds in cells via enzyme-catalysis to form ATP, and can take place in the presence or absence of oxygen. The first step, glycolysis, involves breaking down glucose into pyruvate and a small amount of ATP in the cytoplasm without oxygen. Aerobic respiration occurs when oxygen is present, with pyruvate being broken down into carbon dioxide and water in the mitochondria, producing a large yield of ATP. Anaerobic respiration takes place without oxygen, with pyruvate being converted to lactate in human cells or ethanol and carbon dioxide in yeast cells.

1. Topic 3.7 – Cellular Respiration

2. Cellular Respiration is the controlled release of
energy from organic compounds in cells to form ATP
via enzyme-catalysis. Take place in mitochondria.
Can take place in the presence or absence of oxygen
3.7.13.7.1

3. ATP (adenine triphosphate)
Adenine, Adenosine, Ribose, Phosphate Groups
Used as an energy source in the cell for various purposes.
3.7.13.7.1

4. The first step of cell
respiration is glycolysis,
which involves breaking
down glucose into
pyruvate and a small yield
of ATP.
Takes place into the
cytoplasm and does NOT
require oxygen.
Glucose  2 pyruvate + 2 ATP + 2 NADH
3.7.23.7.2

5. Anaerobic Respiration
When oxygen is not available, cells use anaerobic
respiration to obtain energy (ATP).
In human cells, glycolysis is carried out in the cytoplasm
and the resulting pyruvate is covered to lactate (both 3
carbons). Called lactic fermentation.
3.7.33.7.3

6. Anaerobic Respiration
When oxygen is not available, cells use anaerobic
respiration to obtain energy (ATP).
In yeast cells, glycolysis is carried out and the resulting
pyruvate(3C) is converted into ethanol (2C) and carbon
dioxide (1C). Called alcoholic fermentation.
3.7.33.7.3

7. Anaerobic Respiration
During intense exercise, our body is only able to supply a
limited amount of oxygen to the muscles (aerobic
respiration).
The oxygen delivered is not enough to produce enough
energy to contract muscles at the proper rate, so when it is
used up, cells use anaerobic respiration to release more
energy. Buildup of the lactate produced can cause muscle
cramps.
3.7.33.7.3

8. Anaerobic Respiration
Yeast is used in bread making so that dough will rise.
Glucose  Pyruvate  Carbon Dioxide
+ ATP + Ethanol
The carbon dioxide created
when pyruvate is converted
creates bubbles in the dough
which cause it to rise. Ethanol
produced is evaporated during
the baking process.
3.7.33.7.3

9. Anaerobic Respiration
Glucose
Pyruvate + 2 ATP + 2 NADH
Lactate Carbon Dioxide
& Ethanol
glycolysis
humans yeast
3.7.33.7.3

10. Aerobic Respiration
When oxygen IS present, aerobic respiration is used to obtain
energy. After glycolysis, pyruvate moves from the cytoplasm
into the mitochondria.
There, it is broken down into carbon dioxide and water with a
large yield of ATP. Produces much more energy than
anaerobic respiration or glycolysis. Uses O2.
CO2
Glucose  Pyruvate  H2O
ATP
3.7.43.7.4

11. 3.7.43.7.4

12. 3.7
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 and water with a large yield of ATP.