Search Results

How proteins function? How do proteins work?

By: HWC, Views: 7403

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...

Miller's reaction chamber experiment Animation

By: HWC, Views: 1320

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. ...

Mechanism of enzyme action

By: HWC, Views: 7611

■ 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...

Osmosis - water transport

By: HWC, Views: 7861

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: 6919

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...

Urinary System Animation

By: Administrator, Views: 1292

The urinary system: kidneys, ureters, bladder, and urethra with expanded view of a nephron and the urine-filled space within a bladder. Urinary system: two kidneys, two ureters, one bladder, one urethra. Also called the excretory, genitourinary (GU), or urogenital (UG) system. Produces, stor...

Mechanisms of capillary exchange (transcytosis & bulk flow)

By: HWC, Views: 7406

■ 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...

Conduction of action potentials

By: HWC, Views: 7894

• 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 ...

Language Areas Animation

By: Administrator, Views: 10901

Specific language areas of the brain. Many cortical (and non-cortical!) regions are involved in language processing. The primary language pathway begins in Wernicke’s area (posterior temporal lobe), which receives information from the auditory and visual cortices and assigns meaning (= lang...