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Action potentials - electrical characteristics and generation

By: HWC, Views: 7584

• An action potential is the nervous impulse or signal for long distance communication. Each action potential is generated at the cell's trigger zone. • Action potentials are considered an all-or-nothing phenomena because they are either generated or not. • The generation of an action...

Second Messengers in the Inositol-lipid Signaling Pathway

By: HWC, Views: 7010

Extracellular signals produce specific responses in target cells through the action of intracellular second messengers. Here, we focus on three second messengers, IP3, DAG, and Ca2+, all involved in the inositol-lipid signaling pathway. A hormone-receptor signal on the cell surface leads to the a...

Nucleic acid digestion - brush border enzymes, end products & transport mechanism

By: HWC, Views: 7528

• Further digestion occurs at the microvilli (brush border) of the epithelial cells of the villi in the small intestine. • Two brush border enzymes complete nucleic acid digestion: • Phosphatases, which catalyze the cleavage of a phosphate to form a nucleoside (nitrogenous base and pent...

Nervous pathway to the Neuromuscular (NMJ)

By: HWC, Views: 8286

• A nervous impulse, also called an action potential, starts from the brain or spinal cord to signal skeletal muscle cell contraction. Action potentials continue along a motor neuron to the muscle cell. • The signal to contract must cross a synapse - the neuromuscular junction (NMJ) - betwe...

Power Supply Polyacrylamide Gel Protein Sample

By: HWC, Views: 7106

SDS-polyacrylamide gel electrophoresis is a powerful tool, which resolves proteins according to their molecular weights. Because proteins differ in size, shape, and charge, a protein sample is first denatured with the anionic detergent SDS. When the sample is heated, the SDS molecules bind to ...

Neurotransmission at chemical synapses & Excitory and inhibitory potentials

By: HWC, Views: 7668

• A series of events occur at chemical synapses in order to communicate with the adjacent cell. • The action potential arrives at the presynaptic membrane. • The depolarization phase of the action potential opens voltage gated Ca+ channels. • increased inflow of Ca+' into the cyto...

Role of transport in a cell

By: HWC, Views: 7877

Transport of chemicals across the plasma membrane provides the following functions: Importing molecules for the maintenance of metabolic processes. Exporting chemicals produced by the cell or waste products. Communicating with other cells, allowing for the generation and conduction of a...

Protein catabolism - deamination

By: HWC, Views: 7893

• Digestion hydrolyzes proteins into amino acids, which are transported to the bloodstream. • Amino acids and proteins are not stored. • Instead, they are: • Oxidized to generate ATP. • Used to synthesize new proteins. • Converted to carbohydrates or lipids for storage (if e...

Junction Types - Tight and Adherens Junctions

By: HWC, Views: 8046

Many tissues contain in tercellular junctions between cells. 1. Tight junction 2. Adherens junction 3. Desmosome 4. Hemidesrnosome 5. Gap junction 1. Tight junction • Web-like strips of proteins fuse together adjacent plasma membranes. • Tight junctions prevent the transport...