Today: Nutrition and Digestion Next Week: Circulation, Respiration, and Reproduction

During digestion complex molecules are broken down and then used to build needed molecules and to produce energy

Food Pyramid based on 2,000 calories/day

Federal Food Subsidies vs Food Pyramid

Protein needed per day = 0.8g/kg of body weight So a 150 lb person needs 54 g or 2 oz of protein/day

20 amino acids CB 5.17

8 Essential Amino Acids CB 41.10

Many cultures combine these foods in their traditional diets: beans and rice, beans and corn, peanut butter on bread, soy and rice, lentils and bread or rice CB 41.10

The Calorie Restriction Society for people trying to live longer by eating fewer calories

Regulation of Drosophila Life Span by Olfaction and Food-Derived Odors S Libert, J Zwiener, X Chu, W VanVoorhies, G Roman, S Pletcher Science Vol. 315: February 2007

Calorie Restricted Flies Normal Diet Flies Smelling food reduces life span in CR flies Fig 1

Flies with a poor sense of smell live longer Or83b is a gene involved in the fly’s sense of smell Fig 2A

Fig 4B Flies lacking the Or83b gene are resistant to starvation

Calorie Restricted Flies Normal Diet Flies Smelling food reduces life span in CR flies Fig 1

Calorie Restriction related websites:

JAMA, November 7, 2007—Vol 298, No. 17 pg Cause-Specific Excess Deaths Associated with Underweight, Overweight, and Obesity Flegal KM et al JAMA, November 7, 2007—Vol 298, No. 17 pg Overweight (BMI 25-30) people live longer than normal (BMI ), underweight (BMI 30) people

JAMA, November 7, 2007—Vol 298, No. 17 pg Overweight people live longer than normal, underweight, or obese people for all causes of death CVD= cardiovascular disease

JAMA, November 7, 2007 Vol 298:

CB The Digestive System

CO 2 + H 2 OC 6 H O 2 CO 2 + H 2 O C 6 H O 2 light sugar Photosynthesis Cellular Respiration ATP energy ADP

Energy used Energy released Cells store energy in ATP

Using ATP

Complex molecules are broken down and then used to build needed molecules and to produce energy

Animals take in complex molecules from the environment for energy production

Animal digestion occurs outside of our cells.

animal and fungal digestion occurs outside of our cells.

CB Physical digestion: liquefying of food Chemical digestion: breaking large molecules into small molecules