Transcript Cellular Respiration

CELLULAR
RESPIRATION
The process where organisms obtain
most of their ATP is called Cellular
Respiration
Cellular respiration occurs in the
mitochondria of the cell.
Cellular respiration occurs in two parts:
aerobic respiration and anaerobic
respiration.
Aerobic respiration requires the presence of oxygen.
Anaerobic respiration requires a lack of oxygen
Anaerobic respiration: Glycolysis
Glycolysis
occurs in the
cytoplasm
around the
mitochondria.
The steps of Glycolysis are as follows:
• One glucose molecule is
broken down to 2 G3P
molecules. Two molecules of
ATP are used in this process.
• Each G3P is converted into a
3-carbon molecule called
Pyruvate. During this
conversion, 2 ATPs are
formed from ADP and 2
NADHs are formed from
NAD+. ATP and NADH are
both energy storage
molecules.
Aerobic respiration: The Krebs Cycle and
the Electron Transport Chain
• The Krebs Cycle occurs in the mitochondrial matrix.
Before entering the cycle:
• Pyruvate reacts with a molecule called coenzyme A to form a
2-carbon molecule called Acetyl CoA. During this conversion,
one molecule of carbon dioxide and one molecule of NADH is
formed.
In the Cycle:
• A four carbon compound reacts with acetyl CoA
to create a 6-carbon molecule called citric acid.
• Citric acid is broken down to a five carbon
compound. During this conversion, one molecule
of NADH is released and one molecule of carbon
dioxide is released.
• The five carbon molecule is broken down to a
four carbon molecule. During this conversion,
one carbon dioxide, one ATP, 2 NADHs, and
FADH2 is formed. ATP, NADH, and FADH2 are all
energy storage molecules.
The Electron Transport Chain:
• NADH and FADH2 release electrons that travel through the
mitochondrial membrane. They also create a concentration
gradient by releasing H+ into the mitochondrial matrix.
• The H+ ions travel through a molecule called ATP Synthase
and allow the formation of ATP.
• Each NADH produces three ATP molecules and each
FADH2 produces 2 ATP molecules