1. CELL RESPIRATION & METABOLISM
Dr. Perkins

2. PURPOSE OF CELL RESPIRATION
TO MAKE ATP
Adenosine triphosphate
Metabolism is actually the sum total of all the chemical reactions in the body that break down molecules and rebuild them. To make ATP, or to consume energy
Catabolism is all the chemical reactions in the body that break down molecules to make ATP 
Anabolism is all the chemical reactions in the body that build molecules into new body structures

3. What is ATP? It’s the universal energy carrier
Phosphate groups
ATP
Energy P
Hydrolysis
Adenine
Ribose
H2O
Adenosine diphosphate
Adenosine Triphosphate +
ADP
This reaction represents the hydrolysis of ATP, which releases energy.

4. Anabolism + Catabolism = Metabolism
Your “Metabolism”
Food breakdown leads to:
Release of energetic electrons
Capture of electrons by NAD+ to make NADH
This drives the synthesis of ATP
Metabolism = all reactions in the body that involve energy transformation
Anabolism + Catabolism = Metabolism

5. Cellular Respiration
“Anaerobic” = “without oxygen”
“Aerobic” means “with oxygen.”
Aerobic respiration produces about 20 times more ATP than
Anaerobic respiration.
But anaerobic respiration provides the ATP we need if we need short bursts of energy.

6. A Metabolic Pathway is…
Cellular Respiration consists of metabolic pathways..
A Metabolic Pathway is…
series of enzyme-controlled reactions leading to a product
each new substrate is the product of the previous reaction
SOME REACTIONS ARE ENDERGONIC; OTHERS ARE EXERGONIC

7. OVERVIEW

8. GLYCOLYSIS STARTS WITH GLUCOSE
GLUCOSE IS A simple sugar
(C6H12O6)
Atoms held together by covalent bonds
Glucose

9. Electrons transfer energy between molecules.
GLYCOLYSIS
One 6-carbon glucose is “oxidized” to form two 3-carbon PYRUVATE molecules
Electrons transfer energy between molecules.
Molecule “A” gives up electrons, and is oxidized.
Molecule “B” receives electrons is reduced.
NAD
NADH

10. Glycolysis Occurs in Two Stages
2. Energy is released as ATP or electrons
1. ATP Energy is added to Glucose

11. fructose1,6-bisphosphate
1. ENERGY-REQUIRING STEPS OF GLYCOLYSIS
IN THE CYTOSOL
GLUCOSE
ADP P
ATP
glucose-6-phosphate
2 ATP are required for glycolysis.
fructose-6-phosphate P
ATP
fructose1,6-bisphosphate P
ADP
PGAL P

12. Energy-Releasing Steps
2. ENERGY-RELEASING STEPS OF GLYCOLYSIS P P
PGAL
PGAL
NAD+
NAD+
IN THE CYTOSOL Pi
NADH Pi
NADH P P P P
1,3-bisphosphoglycerate
1,3-bisphosphoglycerate
ADP
ADP
ATP
ATP P P
3-phosphoglycerate
3-phosphoglycerate
4 ATP and 2 NADH are produced in glycolysis. P P
Energy-Releasing Steps
2-phosphoglycerate
2-phosphoglycerate
H2O
H2O P P
PEP
PEP
ADP
ADP
ATP
ATP
pyruvate
pyruvate

13. Q: WHAT IS THE PURPOSE OF NADH?
REVIEW
A: NADH RECEIVES ELECTRONS IN A REDOX REACTION
FADH is also an electron carrier and it works just like NADH

14. LACTIC ACID FERMENTATION
Pyruvate is converted to LACTIC ACID
Benefit: NAD+ is produced, which can be used for glycolysis to help make 2 ATP (just a little).
LACTIC ACID causes soreness in skeletal muscle
Note: the heart only respires aerobically. RBCs only use lactic acid fermentation because they lack mitochondria.

15. Cori Cycle: Lactic Acid is Converted Back to Pyruvate in the Liver
-- the amount of oxygen you need to convert lactic acid to pyruvate is called “oxygen debt.”
Lactic acid dehydrogenase
The liver can convert pyruvate to G-6-P  glucose  release to blood

16. Not Enough Oxygen to the Heart:
CLINICAL APPLICATION:
Not Enough Oxygen to the Heart:
Myocaridal ischemia refers to inadequate blood flow to heart muscle. Sometimes called
coronary heart disease because of inadequate blood flow in coronary arteries.
atherosclerotic heart disease
Prolonged ischemia can cause death of heart cells, which leads to myocardial infarction (heart attack).
When lactic acid builds up in heart muscle, chest pain (angina pectoris) results.
TREATMENT: nitroglycerin, which improves blood flow.