1. Biochemistry of Digestion
BIG IDEAS
Biochemistry of Digestion

2. Element vs. Compound Pure substance
All elements are organized on the Periodic Table
Represented by a Chemical Symbol
Cl – Chlorine
I – Iodine
O2 – oxygen gas
2 or more different elements chemically combined
Represented by a Chemical Formula
NaCl – table salt
H2O – water
CO2 – carbon dioxide

3. Organic vs. Inorganic RARELY contains the element carbon (C) Examples:
NaCl
H2O
Never living
Contains the element carbon (C)
Often includes other elements such as hydrogen (H), oxygen (O), phosphorus (P), nitrogen (N), sulfur (S)
Examples:
C6H12O6 (glucose)
CH4 (methane gas)
C3H6O3 (lactic acid)
Is or once living
Carbohydrates - energy: bread, fruit, vegetables
Proteins - structure: meat
Lipids – energy storage, cell membrane: fats, oils
Nucleic Acid: DNA

4. So why should I care about organic compounds?
Organic compounds are broken apart and recycled by the body to function and grow

5. Physical vs. Chemical Digestion
SAME substance
Change in appearance or location
AKA Mechanical digestion
Examples:
Crushing, grinding, tearing food with teeth
Swallowing food
Peristalsis: pushing or squeezing of food
Bile breaks fat into tiny fat droplets
NEW substance
Change in properties
Examples:
Enzymes, saliva, and stomach acid help to break bond of compounds to form simpler substances
Saliva in mouth breaking down carbohydrates
Pepsin breaks down protein in the stomach
Energy transformation and absorption by the villi in the small intestines

6. LARGE MOLECULES  small molecules
Carbohydrates are large molecules
Complex carbohydrates are also called starches
Chemical digestion or carbohydrates begins in the mouth
Sugar is a smaller molecule

7. LARGE MOLECULES  small molecules
Large molecules (carbohydrates)are like a long train of multiple box cars (smaller molecules, sugar) linked together
Digestion breaks the bonds between compounds

8. Energy Transformations in organisms
Radiant energy  Chemical energy (photosynthesis)
Food people eat has stored chemical energy
Chemical energy  Thermal energy (digestion)
Chemical energy  Heat energy (digestion)
Chemical energy  Mechanical energy (moving)
Mechanical energy  Heat/Thermal energy

9. Law of Conservation of …
ENERGY cannot be created or destroyed, only rearranged
Organisms must eat to obtain energy
MATTER cannot be created or destroyed, only rearranged
Organisms recycle or chemically change food (matter) for their needs