24

Animations
(Animation Requirements)

• Stomach Digestion
• Nutritional Mode of a Clam Compared to a Squid
• Dental Caries
• Digestion
• Endoscopy
• Ulcers
• Small Intestine Digestion
• Formation of Gallstones
• Kidney Function I

Art Labeling Activities

• Wall of Digestive Tract
• Anatomy of Kidney and Lobe

Dieting. Almost all of us at one time or another worry about our weight. It turns out there's a lot of interesting biology involved.

1. Impossible dreams: Fad diets and our futile search for an easy way to lose weight.
2. Why fat people are hungrier.
3. New drugs reduce cholesterol by inhibiting a key enzyme used in manufacturing it.
4. Diet drugs may be good news for those of us who are overweight.
5. Despite earlier hopes, high-fiber diets don't seem to protect against colon cancer.
6. The turkey's revenge; Why eating Thanksgiving dinner puts on the pounds.
7. In the battle to lose weight, I seem to be losing.

FAD Diets
FAD diets like the Atkins diet are wildly popular, because they promise pain-free weight loss. The combination of hope and hype make this diet, and others like it, perpetual best sellers. The secret of the Atkins diet, put simply, is to avoid carbohydrates. Follow it, and you lose weight rapidly--at first. The temporary weight loss turns out to have a simple explanation: because carbs act as water sponges in your body, depleting your body of carbs causes it to lose water. Government studies have shown that those who achieve longer-lasting benefits from the Atkins diet, or other fad diets like The Zone, work not for the bizarre reasons claimed by their promoters, but simply because they are low-calorie diets. There are two basic laws which no diet can successfully violate: 1. all calories are equal, 2. calories in minus calories out equals fat. The fundamental fallacy of all fad diets is the idea that somehow carbohydrate calories are different from fat and protein calories. This is scientific foolishness. Every calorie contributes equally to your weight, whatever its source. The diets work simply because they obey the second law. By reducing calories in, they reduce fat.

Discovering the Virus Responsible for Hepatitis C
Hepatitis is a sometimes fatal disease of the liver caused by a virus. There are three distinct forms. Infectious hepatitis or hepatitis A is transmitted by contact with feces from infected individuals. Serum hepatitis or hepatitis B is passed through the blood and other body fluids. A third form called hepatitis C, caused by the hepatitis C virus (HCV), eluded doctors and researchers for many years. It was only isolated in 1990. It too is transmitted through the blood. Hepatitis B and C cause chronic liver damage that can be fatal. Because these viruses are transmitted through the blood, a diagnostic antibody test was necessary to protect the nation's blood supply from contamination. Although a diagnostic test had been developed for the hepatitis B virus, the hepatitis C virus proved challenging because HCV cannot be grown reliably in a laboratory culture and it is strictly a primate virus (infecting only humans, chimpanzees, and tamarins).

A research team lead by Michael Houghton at Chiron, a California biotechnology company, developed a diagnostic antibody test for HCV. With the HCV diagnostic test in hand, they set out to test its specificity and sensitivity.