Search results for: 'Molecules and Membrane'

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By: HWC, Views: 7615

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

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Muscle cell structures - actin, myosin and titin filaments

By: HWC, Views: 7894

Once the muscle cell has been excited it will contract. • A muscle action potential will trigger the release Of Ca2+ ions into the sarcoplasm. • The Ca2+ ions bind to the regulatory proteins and trigger contraction. • Within skeletal muscle cells are structures that provide the ability...

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The pH scale - Strong acids and Weak acids

By: HWC, Views: 7783

The pH scale • Expresses concentration of H+. • range: 0-14. • 7 is neutral. • Less 7 is acid. • greater 7 is basic (alkaline). Strong acids - role in the body ■ In strong acids all molecules dissociate. ■ HC1 is highly acidic and found only in the stomach. • H...

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Lipid digestion - mouth, stomach and small intestine

By: HWC, Views: 7808

• Lipid digestion takes place primarily in the small intestine; some occurs in the mouth and stomach. • Lipases are enzymes that break down triglycerides and phospholipids. • Lingual and gastric lipases hydrolyze a small amount of triglycerides. • End products are fatty acids and...

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Cytotoxic T cell receptors, activation, proliferation, differentiation & action

By: HWC, Views: 8060

• Most cells which have CD8 on their surface become cytotoxic T cells (Tc cells). • CD8 T cells recognize a foreign antigen when it is presented in conjunction with the protein, MHC-I. • Nearly all nucleated cells in the body express MHC-I molecules. • T cells that recognize self-pe...

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Polysaccharides

By: HWC, Views: 7328

More complex sugars are called polysaccharides (from "poly" meaning "many" and "saccharum" meaning "sugar"). Many things in nature are made of polysaccharides. Here we show one of the polysaccharides in corn, another in wood, and another in the exoskeletons of insects like grasshoppers. How are a...

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Mechanisms of capillary exchange (transcytosis & bulk flow)

By: HWC, Views: 7412

■ 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...

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Proteins Defined, Hierarchy & Composition of Cells

By: HWC, Views: 7215

Proteins are long chains of amino acids linked together by peptide bonds. Together with the other three biological macromolecules—carbohydrates, lipids, and nucleic acids—proteins are the building blocks of cells. Proteins are the most complex and abundant biological macromolecules in cel...

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T cell receptors

By: HWC, Views: 7431

• T cells are responsible for cell-mediated immunity. • Each T cell contains a unique form of T cell receptor (TCR) on its membrane. • These T cell receptors are produced through a process of genetic recombination which is able to produce millions of different variations. • Each T ce...

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