Lipids and Cell Membranes Overview

Membrane Proteins

• Integral membrane proteins penetrate the cell membrane.

Bile Acids

• Bile acids help in the digestion and absorption of fats by emulsifying them in the small intestine.

Lipoproteins

• Low-density lipoprotein (LDL) is considered "bad cholesterol" and carries cholesterol from the liver to the tissues.

Cholesterol Conversion

• Approximately 500 mg of cholesterol is typically converted to bile acids and eliminated in bile daily.

Estrogen

• Estrogen is the primary hormone responsible for regulating the menstrual cycle and the development of female secondary sex characteristics.

Progestins

• Progestins play a crucial role during pregnancy by preparing the uterus for implantation and maintaining the pregnancy.

Unsaturated Fatty Acids

• Increasing the degree of unsaturation in fatty acids lowers their melting point, making them more liquid at room temperature.

Androgens

• Androgens are a group of hormones that promote the development and maintenance of male sexual characteristics.

Fatty Acid Classifications

• Branched-chain fatty acids are not a recognized classification of fatty acids.

Unsaturated Fatty Acids Configuration

• Naturally occurring unsaturated fatty acids generally have a cis configuration around their double bonds.

Emulsifiers

• Emulsifiers enhance the digestion and absorption of fats by breaking down large fat globules into smaller droplets.

Fatty Acid Nomenclature

• The notation 18:3(Δ9,12,15) represents an 18-carbon fatty acid with 3 double bonds located at carbon positions 9, 12, and 15.

Common Fatty Acid Characteristics

• Even number of carbon atoms and a carboxyl group are common characteristics of fatty acids present in naturally occurring lipids.

Polyunsaturated Essential Fatty Acids

• Polyunsaturated essential fatty acids are critical for various functions, including cell membrane integrity and hormone production.

Omega-3 Fatty Acids Sources

• Flaxseed oil is a rich source of omega-3 fatty acids.

Unsaturated Fatty Acids Packing

• The presence of double bonds in unsaturated fatty acids prevents them from packing as tightly as saturated fatty acids, making them more fluid at room temperature.

Lipid Common Characteristic

• Insolubility in water is a common characteristic of all lipids.

Energy Storage Lipid

• Triacylglycerols (fats and oils) are primarily involved in energy storage.

Protective Lipids

• Waxes serve a protective function in organisms by forming a water-repellent coating.

Fats vs Oils

• Fats are solid at room temperature, while oils are liquid at room temperature.

Triacylglycerols

• Triacylglycerols consist of glycerol esterified with three fatty acid molecules.

Lipids Functions

• Transport of oxygen is not a function of lipids.

Phospholipids Role

• Phospholipids play a critical role in forming the cell membrane and acting as signaling molecules in the body.

Fats and Oils Common Property

• Hydrophobic nature is a common property of fats and oils at room temperature.

Fatty Acid Structural Characteristic

• A long-chain hydrocarbon tail with a carboxyl group at one end defines the primary structural characteristic of fatty acids.

Fatty Acids Water Solubility

• Water solubility of fatty acids decreases with increasing carbon chain length.

Fatty Acids Melting Point

• Fatty acids with shorter chains and more double bonds have lower melting points compared to those with longer chains and fewer double bonds.

Fatty Acid Classification

• Medium-chain fatty acids are a class of fatty acids with carbon chain lengths between 6 and 12 carbons.

Alpha Carbon

• The second carbon atom from the carboxyl group is referred to as the alpha (α) carbon in a fatty acid.

Biological Waxes Uses

• Insect communication is not a typical use for biological waxes.

Fatty Acid Structure Component

• Phosphate group is not a component included in the structure of fatty acids.

Fatty Acid Synthesis

• Fatty acid synthesis occurs in the cytoplasm of cells.