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Results for: 'is a weak acid. • Few molecules dissociate because a strong attraction exists between H and HCO5. درجة الحموضة: ھو مقیاس لتحدید تركیز أیونات الھیدروجین H في المحلول یُرمز لدرجة الحموضة بالرمز (pH) وتُعرف أیضاً بالرقم الھیدروجیني أو الأس الهيدروجيني . درجة الحموضة مقیاس مدّرج من 0 إلى 14 ویُعبّر عن تركیز أیونات H وأیونات -OH في المحلول. فالمحالیل الحمضیة تمتلك قیمة pH أقل من (7)، وكلما قلت قیمة pH للحمض زادت قوتھ. والمحالیل القاعدیة تمتلك قیمة pH أكبر من (7)، وكلما زادت قیمة pH للقاعدة زادت قوتھا. أما الماء المقطر فتبلغ قیمة pH لھ (7)، أي أنھ یُعتبر متعادلاً وفق ھذا المقیاس لأن تركیز أیونات-OH مساٍو لتركیز أیونات H تعتمد قيمة PH للمحلول على تركيز كل من أيون الهيدروجين الموجب H وأيون الهيدروكسيد السالب OH-'

Lipid catabolism ( ketogenesis and oxidation of glycerol) and Lipid anabolism (lipogenesis)

By: HWC, Views: 7000

• During excessive beta oxidation, the two-carbon fatty acid fragments are converted into acidic ketone bodies. • Ketosis, the overproduction of ketone bodies, can lead to acidosis (ketoacidosis) of the blood. • After lipolysis, glycerol is converted to pyruvic acid. • Pyruvic aci...

Nucleic acid digestion -small intestine

By: HWC, Views: 6744

Nucleic acid digestion, which takes place in the small intestine, involves: • Pancreatic nucleases. • Brush-border enzymes in the small intestine. • Nucleic acids enter the small intestine dissolved in gastric chyme. • As gastric chyme enters the duodenum of the small intestine, p...

Secretin (inhibiting gastric acid secretion), Cholecystokinin (fat digestion) & Cholecystokinin

By: HWC, Views: 6410

• As chyme approaches the small intestine, secretin also targets acid-producing parietal cells in the gastric mucosa. • Increased secretin inhibits gastric add secretion. • With less gastric acid produced, the chyme going into the intestine is less acidic. • The hormone CCK also reg...

Role of the urinary system - acidosis and alkalosis

By: HWC, Views: 6886

• Tubular cells of the proximal convoluted tubule and collecting tubules can alter filtrate pH and therefore blood pH. • These cells can affect blood pH with two coupled mechanisms: • Reabsorption of bicarbonate ions. • Secretion of hydrogen ions. • The reabsorption of bicarbonate...

Nucleic acid digestion - brush border enzymes, end products & transport mechanism

By: HWC, Views: 6447

• Further digestion occurs at the microvilli (brush border) of the epithelial cells of the villi in the small intestine. • Two brush border enzymes complete nucleic acid digestion: • Phosphatases, which catalyze the cleavage of a phosphate to form a nucleoside (nitrogenous base and pent...

Pores and Ion Channels

By: HWC, Views: 5893

Transmembrane channels, also called membrane channels, are pores within a lipid bilayer. The channels can be formed by protein complexes that run across the membrane or by peptides. They may cross the cell membrane, connecting the cytosol, or cytoplasm, to the extracellular matrix. Membrane po...

Proteins

By: HWC, Views: 5689

Living things must accomplish a great number of tasks just to get through a day, and these tasks are accomplished by a diverse range of biological molecules. In the range of tasks that molecules accomplish, however, proteins reign supreme. Almost every chemical reaction that takes place in living...

How Hemoglobin Picks Up and Delivers Oxygen

By: HWC, Views: 5940

All of the cells in our bodies require oxygen (02) for survival and must release carbon dioxide (CO2) as a waste product. The respiratory and circulatory systems work together as delivery systems for these gases. The lungs exchange these gases between the environment and the bloodstream. The bloo...

Head and Neck Movement Animation

By: Administrator, Views: 299

Interestingly, head and neck muscles are the first ones that the baby can control. A baby can hold his head up before he can sit erect. The muscles of the head and neck perform many important tasks, including movement of the head and neck, chewing and swallowing, speech, facial expressions, an...

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