Thursday, March 31, 2011

What is anaerobic

Cellular processes that do not require oxygen. Energy can be produced in cells without oxygen. Anaerobic GLYCOLYSIS refers to an energy yielding process by which ATP, the energy currency of the cell, is produced from GLUCOSE without the participation of oxygen. As an example, skeletal muscle produces LACTIC ACID and ATP from glucose when oxygen supplied to muscle is inadequate to meet energy needs during strenuous physical exertion.
Accumulated lactic acid is then converted back to glucose during the recovery period following EXERCISE when the oxygen supply is again adequate.
Anaerobic processes are important for certain bacteria as well. Anaerobic bacteria in the intestine grow without oxygen and block the growth of potential disease-producing microorganisms. Anaerobic fermentation of SUGAR by yeast yields alcohol-containing products such as WINE and BEER.

What is anabolism (biosynthesis)?

Processes involved in synthesizing the molecules needed for cellular growth and maintenance. Thus the formation of PROTEIN, DNA, RNA, LIPID, CARBOHYDRATE, FAT, and GLYCOGEN are anabolic processes. Anabolism consumes chemical energy in the form of ATP and NADPH (a reducing agent), which are supplied by CATABOLISM, the energy-yielding oxidative processes involved in degradation. Optimal function and health rely upon a balance of anabolic and catabolic processes (homeostasis). These two branches of metabolism are controlled by the ENDOCRINE SYSTEM, which in turn responds to external influences such as diet. Anabolic processes require small building blocks supplied by breaking down STARCH, PROTEIN, and FAT in foods to build larger molecules. GLYCEROL and FATTY ACIDS are the subunits of fat; AMINO ACIDS yield proteins; and glucose yields glycogen. Fat and carbohydrate degradation provides an energized form of ACETIC ACID (acetyl CoA) to synthesize fatty acids and cholesterol. Other specialized products are also assembled from several different types of smaller precursors. For example, heme, the iron-containing pigment of the oxygen transport protein HEMOGLOBIN, is synthesized from an amino acid (GLYCINE) and SUCCINIC ACID, a common intermediate in energy-producing pathways.
Growth and an anabolic state, seen as an increase in body mass and muscle mass, occur during childhood, adolescence, pregnancy, and strenuous physical activity, such as body building. The weight gained in these situations represents increased protein, bone, or fat, not fluids. Increased fat stores and accumulated body fat represent stored surplus energy in adults and can result from too little exercise, the over-consumption of FOOD, heredity, or a combination of the above factors.

Monday, February 28, 2011

Anabolic Steroids


A family of steroids related to the male sex hormone TESTOSTERONE. These are classified as prescription drugs used to make up for hormone imbalance and deficiencies. However, synthetic analogs of testosterone have been obtained illegally by athletes and by teenage males to build muscles, and the U.S. FDA has described steroid abuse as a drug epidemic. While testosterone stimulates growth during adolescence, the synthetic derivatives can cause many side effects. Athletes compound this unsafe practice by “stacking” anabolic steroids—taking a combination of brands at 10 to 100 times the recommended doses for weeks at a time.
In men, the side effects of anabolic steroid use include lowered sperm count, enlarged prostate gland, shrinking testicles, balding, and enlarged breasts. If taken before puberty, anabolic steroids can stunt growth. These effects seem to be reversible if anabolic steroids have been used for a short time. Some women body builders also use steroids to build muscle. Side effects in women do not seem to be reversible: masculinization, including increased muscles, increased size of clitoris, growth of facial hair, a deepening voice, shrinkage of breast size, uterine atrophy, and menstrual irregularities. Severe cases of acne and bouts of rage are signs of anabolic steroid use, especially in males. Anabolic steroid use can have more subtle, longterm detrimental effects; damage may show up years later as a HEART ATTACK, high blood pressure, CANCER, and LIVER damage in both men and women.

Amylose

A water-soluble form of STARCH found in seeds, tubers, and root vegetables. It is made up of long chains of GLUCOSE units, and often contains a thousand or more glucose units. Amylose differs from the other prevalent form of starch, AMYLOPECTIN, which is highly branched. Amylose forms large spiral configurations when dissolved in water and can react with iodide to form a characteristic blue-purple pigment. Amylopectin and amylose occur together in starch, and the relative amounts vary depending on the plant sources. During digestion, AMYLASE breaks down amylose to maltose, a disaccharide composed of two glucose units. An intestinal enzyme, MALTASE, then hydrolyzes maltose to the simple sugar glucose, the ultimate product of starch digestion.

Amylopectin

The water-insoluble form of STARCH. Plants synthesize this very long chain of GLUCOSE units as a storage form of energy, often to nurture the future embryo, seedling or sprout. It is often the major form of starch and it possesses a highly branched, bushy structure resembling liver GLYCOGEN (animal starch). In contrast, AMYLOSE is made up of single straight chains of glucose units.
Amylopectin forms a paste in hot water. Starch occurs in seeds, tubers, and root vegetables as both amylopectin and amylose, although the ratio of two forms varies with the source. Cooking softens starch granules, making them available to DIGESTION by AMYLASE. The ultimate product of amylopectin digestion is GLUCOSE. Commercial processing converts starch to glucose, then to HIGHFRUCTOSE CORN SYRUP, a major sweetener

Monday, January 31, 2011

Ammonia (NH3) and Human Health


The nitrogen waste produced primarily from AMINO ACID metabolism. Ammonia is highly toxic to the nervous system and the brain. It may interfere with metabolic processes required for energy production in the brain. Normally the brain transforms ammonia into GLUTAMINE, a safe, neutral amino acid released into the bloodstream. Next, glutamine is absorbed by the intestine, which releases the ammonia for disposal by the LIVER. Normally the liver very efficiently metabolizes ammonia to UREA, the ultimate nontoxic waste product, via the UREA CYCLE to keep the level of ammonia in the blood at very low levels. Urea is excreted safely in urine. Ammonia is also produced in the intestinal tract by bacteria. Ammonia is absorbed by the intestine and transported directly via the portal vein to the liver for disposal. Liver disease, such as CIRRHOSIS, reduces urea production and leads to elevated blood levels of ammonia (ammonemia), which causes neurological abnormalities. Genetic defects in the ammoniadisposal mechanism of the urea cycle generally lead to brain damage.

What is amino sugars

A family of nitrogen-containing sugars. Cells attach NITROGEN to the simple sugars GLUCOSE and GALACTOSE to produce GLUCOSAMINE and galactosamine, respectively. These and similar amino sugars are used to produce carbohydratecontaining proteins (GLYCOPROTEINS) that coat cell surfaces, and for structural materials (MUCOPOLYSACCHARIDES) that help form the matrix of cartilage for ligaments and joints.