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Non-polar compounds - insolubility

By: HWC, Views: 7844

• A non-polar molecule has uniform distribution of electrons. • Non-polar compounds like fatty acids in lipids have a high proportion of carbon and hydrogen. • Lipids possess no charge or partial charge. • Lipids are not attracted to water molecules. • Lipids are not soluble in...

Pores and Ion Channels

By: HWC, Views: 6907

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...

Mechanisms of capillary exchange (transcytosis & bulk flow)

By: HWC, Views: 7399

■ This method of capillary exchange is mainly used to transport small amounts of large, lipid-insoluble (water soluble) molecules, such as large proteins. ■ Substances, packaged in vesicles, move through endothelial cells via endocytosis and exocytosis. ■ This method of exchange is th...

Primary Active Transport - electrochemical gradient and ion transport / water movement

By: HWC, Views: 7845

Energy derived from ATP changes the shape of a transporter protein which pumps a substance across a plasma membrane against its concentration gradient An electrochemical gradient is a gradient of electrochemical potential, usually for an ion that can move across a membrane. The gradient consis...

TRH/TSH/Thyroid hormone

By: HWC, Views: 7250

Thyroid hormone production • A decline in metabolic rate caused by increased metabolic need or physical exertion stimulates the production of thyrotropin hormone releasing (TRH) hormone from the cells of the hypothalamus. • Thyrotropin hormone releasing hormone targets the thyrotrophic ce...

Insulin (glucose uptake by body cells), glycogenesis and lipogenesis

By: HWC, Views: 7831

Insulin is the regulator that allows the sugar from the foods we eat (be it a piece of cake or a stick of celery) to enter our tissues and become part of the metabolic process. Insulin is made by the Islets of Langerhans, which are found in the pancreas of every person. As we previously mentio...

Major Elements in Biological Molecules: Lipids

By: HWC, Views: 7044

A triglyceride (also called triacylglycerol) is composed of three fatty acid molecules and one glycerol molecule. The fatty acids attach to the glycerol molecule by a covalent ester bond. The long hydrocarbon chain of each fatty acid makes the triglyceride molecule nonpolar and hydrophobic. Pa...