Search results for: 'urea molecules'

Watch Later 1:29

Oxygen - hemoglobin dissociation curve & Hemoglobin's affinity with oxygen - acidity

By: HWC, Views: 9957

• The partial pressure of oxygen is a primary factor influencing the degree of saturation of hemoglobin. • The Po2 determines the number of oxygen molecules that can bind or dissociate from hemoglobin. • Blood in vessels coming from the lungs is very high in Po2 so saturation is high. ...

Watch Later 1:20

Carbohydrate digestion - mouth and stomach & pancreas and small intestine

By: HWC, Views: 9127

• 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. �...

Watch Later 1:28

The life cycle of protein

By: HWC, Views: 8975

The life cycle of a typical protein begins with its synthesis on a ribosome. As the polypeptide chain grows, molecules of a chaperone protein bind along its length. This prevents misfolding of the nascent polypeptide. ATP binding causes chaperone release. For most proteins, the polypeptide th...

Watch Later 1:56

Role of the urinary system - acidosis and alkalosis

By: HWC, Views: 9540

• Tubular cells of the proximal convoluted tubule and collecting tubules can alter filtrate pH and therefore blood pH. • These cells can affect blood pH with two coupled mechanisms: • Reabsorption of bicarbonate ions. • Secretion of hydrogen ions. • The reabsorption of bicarbonate...

Watch Later 1:24

Endocytosis -Types and Phagocytosis

By: HWC, Views: 9398

Endocytosis is the process by which a substance is brought inside a cell without having to pass through the cell membrane. It is the opposite of endocytosis, the process by which substances exit the cell without having to pass through the cell membrane. Exocytosis – membrane-enclosed secret...

Watch Later 1:39

Lipid absorption - end products & transport mechanism

By: HWC, Views: 8904

• 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...

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Subunits of DNA And Semi Conservative Replication

By: HWC, Views: 5653

Adenine is a purine with a double-ring structure. In double-stranded DNA, adenine base-pairs with thymine. Guanine is a purine with a double-ring structure. In double-stranded DNA, guanine base-pairs with cytosine. Thymine is a pyrimidine with a single-ring structure. In double-stranded DNA, th...

Watch Later 1:42

Second Messengers in the Inositol-lipid Signaling Pathway

By: HWC, Views: 8552

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...

Watch Later 1:32

Hydrogen bonds vs. Ionic bond

By: HWC, Views: 8113

The slight positive charge of a hydrogen atom in a water molecule can attract an atom with a slight negative charge, such as the nitrogen in a molecule of ammonia. This forms a hydrogen bond between the two atoms. Hydrogen bonds join the two strands of a DNA molecule. Although hydrogen bo...

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