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Miller's reaction chamber experiment Animation

By: HWC, Views: 285

A simple diagram of Stanley Miller and Harold Urey's experimental apparatus. The lower portion of the apparatus was filled with water. The upper portion was filled with a mixture of gases that simulated the earth's early atmosphere. Examples are methane, ammonia, hydrogen and carbon dioxide. ...

Role of the urinary system - acidosis and alkalosis

By: HWC, Views: 6882

• 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...

Alternative Energy Sources

By: HWC, Views: 855

Points at which organic compounds enter the reaction stages of aerobic respiration. Complex carbohydrates are broken down into simple sugars, such as glucose. They become the substrates for glycolysis. If your body doesn't need to burn glucose for energy, glucose-6-phosphate can be co...

Plant Defense Mechanisms from Pathogens

By: HWC, Views: 6106

Plants and pathogens have coevolved such that pathogens can recognize plants by the sugars, or other molecules, they produce. Plants, in turn, can recognize pathogens by the molecules they produce. The ability to recognize pathogens allows plants to activate defense systems that can prevent wides...

Gastroesophageal Reflux Disease (GERD)

By: Administrator, Views: 9665

Gastroesophageal reflux disease, or GERD, is a digestive disorder that affects the lower esophageal sphincter (LES), the ring of muscle between the esophagus and stomach. Many people, including pregnant women, suffer from heartburn or acid indigestion caused by GERD.

Peptide Bond Formation Animation

By: HWC, Views: 506

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...

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

By: HWC, Views: 6996

• 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...

Barriers - eye structures, digestive mucosa, respiratory mucosa & genitourinary mucosa

By: HWC, Views: 6895

• Eyebrows, eyelids, eyelashes and conjunctiva serve to trap microbes preventing their invasion. • Tearing (lacrimation) is a protective mechanism that washes away microbes that attempt to enter the eyes. • Salts, mucus, and lysozymes in tears neutralize substances and bacteria. â€...

Biological organic compounds

By: HWC, Views: 6083

Biological organic compounds contain covalent bonds, mainly C-C and C-H bonds, but also both C and H bonded to such other atoms as O and N. Some of these covalent bonds are nonpolar. Others are polar, either because one atom in the group "hogs" electrons away from other atoms in the group, or...