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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-'

Peptide Bond Formation Animation

By: HWC, Views: 513

During protein synthesis, peptide bonds link amino acids together in the order specified by DNA instructions. In this case, the first two amino acids in the protein are methionine and alanine. Here are ball-and-stick models of these amino acids. Peptide bond formation is a type of condensatio...

SNP Polymorphysim Microarray Chip - How to Test a Person's DNA

By: HWC, Views: 5964

To test a person's DNA, a researcher first needs a source of tissue. Most of the cells in a blood sample are red blood cells, which lack nuclei, but there are also a number of white blood cells, which do contain nuclei and chromosomal DNA. If we could see a particular DNA sequence in these cel...

Hershey Chase Experiments

By: HWC, Views: 3823

Hershey and Chase knew that T4 bacteriophages consist of proteins and DNA. They asked which viral component must enter a bacterial cell to infect it: DNA or protein? They grew viruses with either radioactive sulfur, which labels the viral protein, or radioactive phosphorus, which labels DNA. ...

Haustral churning, Gastrocolic reflex and mass peristalsis & Defecation

By: HWC, Views: 6796

• As the cecum becomes filled and distends, a local reflex causes: • Closure of the ileocecal valve. • Activation of haustral churning. • Haustral churning mixes the chyme, which helps absorption of water, salts, and vitamins. • Haustral churning propels the contents of the colo...

Stomach peristalsis - Movement of Food Through the Small Intestine

By: HWC, Views: 6688

Peristalsis is a series of wave-like muscle contractions that moves food to different processing stations in the digestive tract. The process of peristalsis begins in the esophagus when a bolus of food is swallowed. The strong wave-like motions of the smooth muscle in the esophagus carry the food...

Major Elements in Biological Molecules: Carbohydrates

By: HWC, Views: 6225

Carbohydrates include simple sugars (monosaccharides) as well as large polymers (polysaccharides). Glucose is a hexose, a sugar composed of six carbon atoms, usually found in ring form. A starch macromolecule is a polysaccharide composed of thousands of glucose units. Glucose molecules can be ...

Splitting of Sugar, Oxidation/ Reduction & ATP Generation

By: HWC, Views: 6380

The next reaction shows us the meaning of "glycolysis" or the splitting of glucose. The fructose bisphosphate molecule is split into two molecules each containing 3 carbons as the backbone. FBP is split into two 3-carbon molecules called G3P, or glyceraldehyde 3-phosphate. Notice that the phos...

Types of energy transfer reactions: oxidation-reduction reactions and ATP generation reactions

By: HWC, Views: 7210

■ Metabolism balances anabolic and catabolic reactions. ■ Anabolism is energy transfer from ATP to simpler molecules in order to build them up into larger, more complex molecules. ■ Catabolism is breaking down larger, more complex molecules, usually to transfer energy from them in order...

Types of Transport - Uniport, Antiport and Symport (Glucose and Na+K+ Transporters)

By: HWC, Views: 6273

Some transport proteins bind and transport molecules very selectively. Uniport is the transport of one solute molecule. Symport is the transports of two solute molecules in the same direction. Antiport is the transports of two solute molecules in opposite directions. 1. Glucose bin...

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