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The Cholesterol Content of Selected Meats and Dairy Products.

The Cholesterol Content of Selected Meats and Dairy Products. Cholesterol and fats transported thru bloodstream in the form of round particles called lipoproteins. low-density lipoproteins (LDL) & high-density lipoproteins (HDL) are most common.

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The Cholesterol Content of Selected Meats and Dairy Products.

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  1. The Cholesterol Content of Selected Meats and Dairy Products. Cholesterol and fats transported thru bloodstream in the form of round particles called lipoproteins. low-density lipoproteins (LDL) & high-density lipoproteins (HDL) are most common.

  2. Cholesterol molecules fit between fatty acid chains in a lipid bilayer. They regulate the rigidity of the structure.

  3. Membranes are selectively permeable • Small polar molecules, gases, free to go through (CO2, H2O, O2, etc) • Large hydrophobic orlipid solublemolecules can go through • Physical processes (not chemical) • Osmosis • Diffusion • Other molecules (like glucose) must move through channels usingmembrane transport proteins

  4. Three Transport Processes • Diffusion

  5. Membrane Transport • Facilitated Transport • Carrier proteins (transporters) • Create a pathway through the phospholipid bilayer for insoluble materials • Like agate • No energy needed • Active Transport • Pump proteins • Pumpions or grab materials for transport • Requires energy (provided by ATP)

  6. Active Transport Na+ / K+ ion pump in a cell membrane: Maintains an electrical & chemical gradient

  7. Bile Acids • Bile acids are di- or trihydroxy cholesterol derivatives • C 17 side chain is oxidized to carboxylate • The carboxylate is bonded to an amino acid • glycine or taurine

  8. Bile acids perform 4 functions: • their synthesis and excretion in the feces is the only significant mechanism for the elimination of excess cholesterol. • 2. bile acids and phospholipids make cholesterol soluble in bile, preventing precipitation of cholesterol in the gallbladder. • 3. facilitate digestion of triacylglycerols - acting as emulsifying agents that render fats accessible to pancreatic lipases. • 4. facilitate the intestinal absorption of fat-soluble vitamins.

  9. Messenger lipids: steroid hormones • Hormonesget cells to do a particular task body-wide (or stop doing it!) • Two categories: • Sex hormones • Estrogens • Androgens • Progestins • Adrenocorticoid hormones • Mineralocorticoids - control Na+ & K+ balance • Aldosterone • Glucocorticoids - control glucose metabolism & • counteract inflammation • Cortisol (hydrocortisone)

  10. Sex Hormones • Adrenocorticoid Hormones

  11. Eicosanoids: derived fromeicosatetraenoic • (arachidonic)acid • (20:4 cis ∆5,8,11,14-6 fatty acid) • Prostaglandins, Thromboxanes, & Leukotrienes: • Structurally related hormones • Wide range of biological effects: • lower gastric secretions • stimulate uterine contractions • lower blood pressure • influence blood clotting • induce asthma-like allergic responses. • Aspirin affects the reactions of many of these hormones.

  12. Arachidonic acid derivatives

  13. Biological Waxes • Lipids that are monoesters of a long-chain fatty acid and a long-chain alcohol. • Water repellent! • Sebaceous glands • Lanolin • Preen glands • Insects • Leaves

  14. CH3(CH2)14CO2-(CH2)15CH3 Spermaceti CH3(CH2)30CO2-(CH2)33CH3 Carnauba wax CH3(CH2)24CO2-(CH2)29CH3 Beeswax Waxes are widely distributed in nature. The leaves and fruits of many plants have waxy coatings, which may protect them from dehydration and small predators. The feathers of birds and the fur of some animals have similar coatings which serve as a water repellent.

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