Bio Notes

Bio Notes - Nutrition and Digestion Protein - twenty amino...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
Nutrition and Digestion Protein - twenty amino acids are found in human proteins, only 12 of which can be produced in the body. The remaining eight are the essential amino acids and must be supplied in the diet. For children, an additional two amino acids must be present in the diet for growth and development. Death due to starvation usually involves insufficient protein, not energy. Children who are deprived of protein often have low blood albumin, causing the retention of water and a bloated appearance. This nutritional disease is called "kwashiorkor". Meat is a good source of all the essential amino acids, but vegetarians must be careful to select foods that compliment each other in amino acid composition (e.g. rice and beans). Vitamins - small organic molecules that facilitate metabolism by serving as "co- enzymes". Thirteen of these are needed for a well-balanced diet. Some vitamins have antioxidant properties (E, C, A) that may protect against cardiovascular disease and plaque formation. Vitamin B-1 -- essential for glucose oxidation. Deficit leads to buildup of lactic acid, especially in nervous tissue and cardiac muscle. Beri-beri is the nutritional disorder that results. Historically (first discovered in the late 1800's), beri-beri has been a serious problem in places where seed coats are removed from cereal grains (e.g. rice) in the milling process. Vitamin C --required for collagen formation. Deficit in the diet leads to damaged connective tissue, bleeding gums, poor healing capacity, etc. collectively known as scurvey. Citrus fruits are a good source. Claims have been made for other roles of Vitamin C in the body--these are controversial Vitamin D --can be synthesized from a cholesterol-based compound produced in the skin by sunlight. Deficit leads to weak bones (rickets), but excess is also harmful (excessive calcium deposition). It has been hypothesized that geographical patterns of skin pigmentation arise from these considerations. Muslim women that wear burka, have an increase chances to  contract rickets, due to the lack of expose of the skin to sunlight.  To much Vitamin D can lead to calcium deposit in places they should  not be, and this can lead to arthritis and other disorder.  Minerals - serve a variety of roles including structural (e.g. calcium), transport (iron), co-enzymes (magnesium),hormonal (iodine). The condition called goiter (swelling of the thyroid gland in the neck) results from diets deficient in iodine. Iodine must be present to activate the hormone thyroxine, produced by the thyroid gland. II. Digestion and Absorption
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
The principle organs involved in digestion are the stomach, small intestine, and large intestine. The stomach is the site of chemical digestion, using enzymes (such as pepsin) and acidic conditions (pH=1.5 2.5). A peptic ulcer is formed when the protective lining of the stomach breaks down. Most ulcers (90%) are caused by an infection by the
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 8

Bio Notes - Nutrition and Digestion Protein - twenty amino...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online