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Protein Secondary and Tertiary Structures - Animation

By: HWC, Views: 3899

Amino acid sequence dictates a protein's final shape. The presence of certain amino acids favors a pattern of hydrogen bonding that causes part of the polypeptide chain to coil and twist into an alpha helix. The presence of other amino acids enables hydrogen bonding between strand like r...

Secondary and tertiary levels of protein structure Animation

By: HWC, Views: 1632

Amino acid sequence dictates a protein's final shape. The presence of certain amino acids favors a pattern of hydrogen bonding that causes part of the polypeptide chain to coil and twist into an alpha helix. The presence of other amino acids enables hydrogen bonding between strand like re...

Protein Structure - Primary, Secondary, Tertiary and Quaternary

By: HWC, Views: 7653

A protein's first order structure, or primary structure, begins with the amino acid sequence of the polypeptide chain. The 20 different amino acids can be arranged in an infinite number of sequences. For example, the hormone insulin, which regulates the uptake of glucose from the blood into ce...

Glucagon (glycogenolysis and gluconeogenesis)

By: HWC, Views: 7586

• Exercise, or not having eaten recently, causes a decline in blood glucose concentration. • Low blood glucose stimulates alpha cells in the pancreatic islets to secrete glucagon. • Glucagon targets liver cells. • Glucagon causes liver cells to undergo: • Glycogenolysis, a proce...

Carbohydrate digestion - mouth and stomach & pancreas and small intestine

By: HWC, Views: 7485

• Digestion of complex carbohydrates (starches and glycogen) involves: • Amylases produced by the salivary glands and pancreas. • Brush-border enzymes in small intestine. • In the mouth, amylase from the parotid and submandibular salivary glands begins carbohydrate digestion. �...

Major Elements in Biological Molecules: Proteins

By: HWC, Views: 7137

Proteins are chains of amino acids linked by peptide bonds. The 20 different amino acids used to make all proteins differ only in their side chains, and the properties of these side chains account for the great diversity of protein structure and function. Collagen is an example of how a prote...

New DNA Strand Replication

By: HWC, Views: 7119

First step: strands are separated • Helicase unwinds the DNA double helix at the replication fork • SSBs coat the single strands to prevent reannealing • Polymerase attaches nucleotide at 3' end • Synthesis is in 5' to 3' direction DNA Polymerase: • Only extends nucleic ac...

DNA Replication Factory and Protein

By: HWC, Views: 7231

DNA (deoxyribose nucleic acid) carries all the genetic information needed to re-create itself and to pass on the characteristics of the organism. The “factory” model of DNA replication hypothesizes a specific nuclear structure in which the molecular machinery for replication forks are brou...

Carbohydrate digestion (brush border enzymes, end products) & Carb absorption (fructose, galactose)

By: HWC, Views: 7706

• Carbohydrate digestion concludes in microvilli of the small intestine, in brush border epithelial cells. Carbohydrate digestion -brush border enzymes • Four brush-border enzymes are involved: • Alpha-dextrinase breaks down alpha-dextrin chains by removing glucose units. • Sucras...