1. The Major Biomolecules
(and how we Digest them)

2. There are 4 major Biomolecules:
-Carbohydrates
-Lipids (Fats)
-Proteins
-Nucleic Acids

3. Carbohydrates -Carbohydrates are the sugars produced by
primary producers through photosynthesis
and the fuel for Cellular Respiration.
-Digestible carbohydrates include sugars and
starches.
-Fruits, Vegetables, and Milk Products, are natural sources of sugar
-Grains have high concentrations of starches

4. Carbohydrates: Monosaccharides
Carbohydrates are built by the 3 basic sugar
monomers: (Note: All are C6H12O6)
Glucose, Fructose, and Galactose

5. Carbohydrates: Disaccharides
-2 monosaccharides combine to form
Disaccharide molecules
Glucose + Glucose = Maltose (Malts)
Glucose + Fructose = Sucrose (Table Sugar)
Glucose + Galactose = Lactose (Milk)

6. Carbohydrates: Digestion
-Chemical Digestion of Carbohydrates occurs in 3 stages:
-Mouth: Salivary Amylase
-Small Intestine: Pancreatic Amylase
-Villi and Microvilli: Membrane-Bound Enzymes

7. Carbohydrates: Absorption & Storage
-After being absorbed into the bloodstream by the
small intestine, sugars travel through the
hepatic portal vein to the liver.
-In the liver, sugars are recombined and stored
as complex molecules called Glycogen
-HOMEOSTASIS: The Pancreas controls the
uptake and the release of blood sugars by the liver.

8. Proteins -All living cells have proteins (Plant and Animal)
-Common Foods with High amounts
of proteins are:
Eggs, Nuts, Beans, Dairy Products, and Meats
-The Many Roles of Proteins: Repair and Build Body Tissues, Hormone Regulation, Enzyme Activity, Immune System Support, Energy

9. Proteins: Structure
-Proteins are large molecules made up of subunits called
amino acids (Over 100 in nature)
-There are 20 unique amino acids that the
body uses, each with its own unique structure VIDEO 2min
-In order to absorb protein from food, we must break them apart into their individual amino acids.
-Our bodies cannot synthesize (make) 8 of the 20 amino acids, and must obtain them from food: These are called ESSENTIAL AMINO ACIDS

10. Proteins: Digestion
-Chemical Digestion of Proteins occurs in 3 places:
-Stomach: Glands release Pepsin enzyme
-Small Intestine: Pancreas releases proteases
-Villi and Microvilli: Membrane-bound enzymes

11. Proteins: Absorption -Amino acids are absorbed individually or in
groups of 2-3 into the capillaries of the villi
-They are taken to the liver
through the hepatic portal vein

12. Lipids (Fats) -Lipids are Fats -They are found in many foods:
Meats, Eggs, Dairy, Avocados,
Nuts, Seeds, Main Component
of Oils

13. Lipids: Roles in the Body
-Provide a concentrated source of Energy
-Regulate Body Temperature (insulate)
-Protect Vital Organs
-Help produce body cells
-Transport Fat Soluble Vitamins
-Used in the production of Hormones and Vitamins

14. Lipids: Molecular Structure
-The most common type of lipid molecule is
the triglyceride, composed of one
Molecule of glycerol and 3 fatty acid chains
-An important feature of lipid molecules
is that the glycerol head is hydrophilic
(water liking), and the fatty acid chains are
hydrophobic (water fearing)

15. Lipids: Digestion -Lipids do not dissolve in water (water insoluble)
-Bile salts are produced by the liver
and secreted by the gall bladder to
break up lipids into small droplets
that can be absorbed into the bloodstream

16. Lipids: Digestion -The smaller droplets are called micelles
-The pancreas secretes lipases that break down
the lipid molecules into 2 fatty acid chains and a
Monoglyceride
-They then diffuse through the villi into the bloodstream

17. Lipids: Absorption
-Because lipids are insoluble, they don’t diffuse like
sugars and amino acids in the bloodstream, instead,
they are put back together as triglycerides,
mixed with cholesterol, fat-soluble vitamins,
and wrapped in a layer of proteins to make
a transport protein called a Chylomicron