1. Biology 212 Anatomy & Physiology I
Nutrition and Metabolism

2. Body requires, among many other things:
a) Water = solvent for all body fluids
b) Electrolytes (ions, minerals) for osmotic balance
electrical signals
Vitamins = cofactors for enzyme-catalyzed reactions,
growth, antioxidants, vision, blood clotting
Proteins
Carbohydrates
Lipids
Structural molecules to build/repair cells and tissues
and
Fuel molecules to produce energy

3. We have already discussed water balance
Let’s focus on the nutritional needs and metabolic uses of
other nutrients which are absorbed into the blood from the intestines and distributed to all other cells in the body.

4. Two types of metabolism:
Catabolism = breaking larger molecules into smaller ones
e.g. proteins amino acids
starch glucose
glucose CO2 + H20 + energy
fatty acid CO2 + H20 + energy
Occurs: digestive system, inside cells
Anabolism = building smaller molecules into larger ones
e.g. glucose glycogen
fatty acids + glycerol triglycerides
amino acids proteins
Occurs: inside cells

5. Body requires, among many other things:
Water = solvent for all body fluids
Electrolytes (ions, minerals) for osmotic balance
electrical signals
Vitamins = cofactors for enzyme-catalyzed reactions,
growth, antioxidants, vision, blood clotting
Structural molecules to replace damaged ones
Fuel molecules to produce energy

6. Human body consumes 2,000 – 5,000 kilocalories per day
and must replace this through fuel molecules in the diet
1 kilocalorie (Kcal) = 1,000 calories
1 calorie = measurement of energy
Specifically = amount of heat necessary to
increase the temperature of one
gram of water by one degree
centigrade
Just to put things in perspective:
5,000 kcal = amount of energy needed to heat 50 kg
(~110 pounds) of water from freezing to boiling

7. kcal/hour
Activity per kg body wt
Running – 9 minute mile
Cross-country skiing
Jogging
Racquetball
Basketball
Swimming
Tennis
9 mph
Hiking
Walking
Housecleaning

8. Primary sources of fuel molecules in diet:
Monosaccharides from breakdown of polysaccharides
(mostly glucose) (mostly starch)
Fatty acids from breakdown of diglycerides & triglycerides
Also possible: amino acids from breakdown of proteins
One gram of fatty acids: kcal of energy
One gram of monosaccharides: 4 kcal of energy
One gram of amino acids: kcal of energy

9. Primary sources of fuel molecules in diet:
Monosaccharides from breakdown of polysaccharides
(mostly glucose) (mostly starch)
Fatty acids from breakdown of diglycerides & triglycerides
Also possible: amino acids from breakdown of proteins
If diet contains more fuel molecules than body needs for immediate needs, the excess can be stored in a variety of cells, e.g. diglycerides & triglycerides in adipocytes
& other cells
glycogen in hepatocytes
myocytes

10. Regardless of type of Complete catabolism results in
fuel molecule used: release of energy which is stored
as adenosine triphosphate (ATP)

11. This ATP can later be broken down to release this energy for cellular functions which need it:
e.g. Active transport of molecules across membranes
Pumping ions for polarization
Moving molecules or organelles within cell
Synthesizing proteins
Contraction of myocytes
Movement of cilia or flagella
etc.

12. Most commonly used fuel molecule = glucose
First stage of glucose catabolism
inside cells = glycolysis
One molecule of
glucose (C6H1206)
produces
2 molecules pyruvic
acid (C3H6O2)
2 molecules ATP
Oxygen not required

13. Most commonly used fuel molecule = glucose
First stage of glucose catabolism
inside cells = glycolysis
One molecule of molecules pyruvic acid
glucose (C6H1206) molecules ATP
If oxygen IS NOT available, pyruvic acid molecules converted to lactic acid, which diffuses out of cell as waste product
produces

14. Most commonly used fuel molecule = glucose
First stage of glucose catabolism
inside cells = glycolysis
One molecule of molecules pyruvic acid
glucose (C6H1206) molecules ATP
If oxygen IS available, pyruvic acid molecules further catabolized in tricarboxylic (“Krebs”) cycle
(Your book may refer to this as the “matrix reactions”)
produces

15. Tricarboxylic acid / Krebs cycle:
Oxygen required
Each pyruvic acid molecule (3 carbons) gives off one carbon atom,
then
combines with 3 molecules of oxygen (O2)
to produce
3 molecules CO2
3 molecules H2O
18 molecules ATP

16. Electron Transport Chain and ATP Synthesis:

17. Thus:
If no oxygen available: 1 glucose yields 2 ATP
If oxygen available: glucose yields 38 ATP

18. Carbohydrates such as starch are readily available in diet
&
Can easily be broken down to form glucose,
which is easily absorbed from intestine into blood
You don’t need all of that glucose immediately for production of energy so
Excess glucose must be removed from blood and stored

19. (Excess glucose must be removed from blood and stored)
1. Joined into glycogen
Primarily in hepatocytes and skeletal myocytes

20. (Excess glucose must be removed from blood and stored)
2. Converted to fatty acids through process of lipogenesis
Bonded to glycerol to form diglycerides & triglycerides

21. Similarly:
If enough glucose not available in diet,
Other molecules, primarily products of fat catabolism
& amino acid catabolism
can be converted to glucose molecules through
gluconeogenesis
and also stored as glycogen; primarily in liver

22. Glucose not only fuel molecule many cells can use
Recall: fatty acids contain long chains of carbon atoms

23. Glucose not only fuel molecule many cells can use
Recall: fatty acids contain long chains of carbon atoms
These can be catabolized by breaking off two-carbon pieces and feeding these into the tricarboxylic acid cycle

24. Body requires, among many other things:
Water = solvent for all body fluids
Electrolytes (ions, minerals) for osmotic balance
electrical signals
Vitamins = cofactors for enzyme-catalyzed reactions,
growth, antioxidants, vision, blood clotting
Structural molecules to replace damaged ones
Fuel molecules to produce energy

25. Recall: Two types of metabolism:
Catabolism = breaking larger molecules into smaller ones
e.g. proteins amino acids
starch glucose
glucose CO2 + H20 + energy
fatty acid CO2 + H20 + energy
Occurs: digestive system, inside cells
Anabolism = building smaller molecules into larger ones
e.g. glucose glycogen
fatty acids + glycerol triglycerides
amino acids proteins
Occurs: inside cells

26. Many macromolecules constantly need replacement through anabolism from smaller molecules, for example:
Amino acids Enzymes, Antibodies,
Contractile proteins,
Membrane proteins,
Lipoproteins
Monosaccharides Glycoproteins,
Nucleic acids, ATP
Fatty acids Glycolipids
+ glycerol Phospholipids
Nucleotides Nucleic acids

27. These anabolic reactions occur by
dehydration synthesis

28. Many of these smaller molecules (monomers) are recycled from catabolism of larger molecules (polymers)
Others must be obtained through diet

29. Amino acids which
can’t be formed from
other amino acids =
Essential amino acids
Fatty acids which
can’t be formed from
other fatty acids =
Essential fatty acids

30. All monosaccharides
can be formed from so no essential monosaccharides
other monosaccharides
Nucleotides can be
formed from other so no essential nucleotides
nucleotides & other
molecules

31. Body requires, among many other things:
Water = solvent for all body fluids
Electrolytes (ions, minerals) for osmotic balance
electrical signals
Vitamins = cofactors for enzyme-catalyzed reactions,
growth, antioxidants, vision, blood clotting
Structural molecules to replace damaged ones
Fuel molecules to produce energy

32. Minerals needed
in the human diet
because
They are being lost in urine, feces, sweat, menstruation, cell death, etc.

33. 13 molecules are recognized as vitamins

34. To maintain homeostasis
1. Fuel molecules, structural molecules, vitamins, minerals,
and water must be obtained through diet
2. Water balance must be maintained
3. Fuel molecules catabolized to produce ATP
4. Large structural molecules formed as
Old molecules broken down and lost
5. Ions used for many purposes
6. Vitamins used for many purposes
7. Waste products must be removed