Topic 4 Lipids

Vocabulary flashcards covering the structure, naming, categories, digestion, and health implications of lipids based on lecture notes.

Fatty Acids

The building blocks of triglycerides and phospholipids, consisting of a chain of carbon (C) and hydrogen (H) atoms with a methyl (omega) end and an acid (carboxyl) end.

Short-chain fatty acids

Fatty acids containing fewer than $6$ carbons; produced by gut bacteria and found in small amounts in dairy.

Medium-chain fatty acids

Fatty acids containing $6–10$ carbons; common sources include coconut oil and palm oil.

Long-chain fatty acids

Fatty acids containing $12+$ carbons; common sources include animal fats and plant oils.

Saturated Fatty Acids

Fatty acids with no double bonds that are solid at room temperature, such as butter, beef fat, and coconut oil.

Monounsaturated Fatty Acids (MUFA)

Fatty acids with one double bond, usually liquid at room temperature; examples include olive oil, avocado oil, and peanut oil.

Polyunsaturated Fatty Acids (PUFA)

Fatty acids with two or more double bonds, usually liquid at room temperature; examples include sunflower oil, fish oils, and corn oil.

Omega-3

A fatty acid where the first double bond is at the $3rd$ carbon from the omega end; an example is alpha-linolenic.

Omega-6

A fatty acid where the first double bond is at the $6th$ carbon from the omega end; an example is Linoleic acid (LA).

Cis Fat

A fatty acid with a bent structure where hydrogens are on the same side of the double bond.

Trans Fat

A fatty acid with a straighter structure where hydrogens are on opposite sides of the double bond; raises LDL and lowers HDL.

Triglycerides

Lipids that make up about $95\%$ of dietary and stored body fat; functions as a source of energy, insulation, and protection of organs.

Phospholipids

Lipids where one fatty acid is replaced by a phosphate group; they serve as a major component of cell membranes and acts as emulsifiers.

Sterols

Multi-ring carbon structures without fatty acids; examples include cholesterol and precursors for Vitamin D, bile acids, and steroid hormones.

Lingual lipase

An enzyme in the mouth that begins minor fat digestion.

Gastric lipase

An enzyme in the stomach that continues fat digestion, breaking about $30\%$ of lipids into diglycerides and free fatty acids.

CCK (Cholecystokinin)

A hormone released by the small intestine that stimulates the gallbladder to release bile and the pancreas to release lipase.

Bile

A substance that emulsifies fat by breaking large fat globules into small micelles to increase surface area for digestion.

Pancreatic lipase

An enzyme that breaks triglycerides into monoglycerides and fatty acids in the small intestine.

Chylomicrons

Lipoproteins formed from long-chain fatty acids, cholesterol, and proteins that transport dietary triglycerides through the lymphatic system.

Lipoproteins

Clusters of lipids and proteins that allow hydrophobic fats to travel through the blood.

LDL ("Bad Cholesterol")

Low-density lipoprotein that delivers cholesterol to cells; excess can oxidize and accumulate in artery walls, leading to atherosclerosis.

HDL ("Good Cholesterol")

High-density lipoprotein that removes cholesterol from the blood and returns it to the liver.

Triglycerides target level

The recommended blood lipid level is less than $1.7\,mmol/L$.

Total Cholesterol target level

The recommended blood lipid level is less than $5.2\,mmol/L$.

LDL target level

The recommended blood lipid level is less than $3.5\,mmol/L$.

HDL target level

The recommended blood lipid levels are greater than $1.3\,mmol/L$ for women and greater than $1.0\,mmol/L$ for men.