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How proteins function? How do proteins work?

By: HWC, Views: 7415

How proteins function is really about how proteins "do work" in cells. How do proteins work? Let's start thinking about protein function by looking at something important to you: your hair. Keratin is a structural protein that is composed of 2 intertwined or helical strands. Keratin is also f...

Mechanism of enzyme action

By: HWC, Views: 7618

â–  The substrate makes contact with the active site. â–  A change in the shape of the enzyme occurs resulting in the transformation of the substrate. â–  A substrate may undergo decomposition, have its atoms rearranged, or two substrates may be synthesized. â–  The products of the reaction...

Osmosis - water transport

By: HWC, Views: 7868

Osmosis is the flow of water down its concentration gradient, across a semi-permeable membrane. Osmosis is an example of diffusion, which is when molecules tend to distribute themselves evenly in a space. what is a semi-permeable membrane? It is a membrane or barrier that allows some molec...

Pores and Ion Channels

By: HWC, Views: 6930

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: 7416

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

Conduction of action potentials

By: HWC, Views: 7901

• Action potentials must be rapidly conducted over long distances in order for the nervous system to communicate with other cells. • Propagation of an action potential uses processes similar to those that generate the potential at the trigger zone. • a When a graded potential reaches ...

Mechanics of Sound Animation

By: Administrator, Views: 11001

Process of Hearing Sound waves are directed to the eardrum, causing it to vibrate. These vibrations move the three small bones of the middle ear (malleus, incus, and stapes). Movement of stapes at oval window sets up pressure waves in the perilymph and endolymph. Process of Hearing The wav...

Uterine (menstrual) cycle - phases

By: HWC, Views: 7731

• The uterus goes through a cyclical developmental pattern to be ready for implantation and support of an embryo. • The uterine, or menstrual, cycle is under the control of ovarian horrnones. • The uterine cycle also has three phases: • Menstrual phase • Proliferative phase â€...

Lipid absorption - end products & transport mechanism

By: HWC, Views: 7276

• 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...