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Import of Dietary Glucose from Intestines to Bloodstream

By: HWC, Views: 6119

• Membranes have hydrophobic interiors. which resist the passage of hydrophilic compounds and ions. • However. transporter membrane proteins facilitate the passage of these molecules. • Passive transporters accelerate diffusion of molecules towards equilibrium (decrease a concentrat...

ribosome

By: HWC, Views: 6334

The trp operon in E. coli contains five structural genes corresponding to enzymes that convert chorismate into tryptophan. The trpE gene contains a 5' untranslated region that plays an important role in the regulatory mechanism called attenuation. The 5' UTR contains four regions. Region 1 en...

Pores and Ion Channels

By: HWC, Views: 5892

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...

Miller's reaction chamber experiment Animation

By: HWC, Views: 288

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. ...

Glucose anabolism reactions: Glycogenolysis and Gluconeogenesis

By: HWC, Views: 7016

• Glucose not needed immediately is stored as glycogen. The process that creates it is glycogenesis. • When ATP is needed for body activities, stored glycogen is broken down by a process called glycogenolysis. • Glucose can be formed through two different anabolic reactions: • Glycog...

Lipid catabolism - lipolysis and beta oxidation and oxidation of fatty acids

By: HWC, Views: 6924

• Digestion hydrolyzes lipids into fatty acids and glycerol. • Fatty acids and glycerol are: • Oxidized to generate ATP. • Used to produce triglycerides that are stored as energy reserves in adipose tissue. • Lipid catabolism begins with lipolysis in which lipids are broken do...

Acids and bases - definition

By: HWC, Views: 6608

Acids and bases are found all around your house. For example, if you open your pantry or refrigerator, you might see a lot of acids. Fruit juice, soda pop, vinegar, and milk are all examples of acids. The word acid actually comes from a Latin term meaning ''sour.'' Many materials, like sugar for ...

Protein digestion - stomach & small intestine

By: HWC, Views: 6094

• Protein digestion occurs in the stomach and small intestine. • The stomach enzyme pepsin initiates the process. • Pancreatic and intestinal brush border enzymes complete the digestive process. • In the stomach, pepsin is created from pepsinogen in the presence of pH-lowering hyd...

Lipid absorption - end products & transport mechanism

By: HWC, Views: 6196

• The end products, fatty acids and monoglycerides, depend on bile salts for absorption. • Bile salts form micelles (tiny spheres), which ferry fatty acids and monoglycerides to epithelial cells. • Free fatty acids, monoglycerides, and some phospholipids and cholesterol molecules, dif...