chapter 5 vocab

Here are clear, concise definitions and explanations for each lipid-related term:

### Fatty Acid

A fatty acid is a long hydrocarbon chain with a carboxyl group at one end. Fatty acids are a building block of fats and can be either saturated or unsaturated.[2]

### Saturated Fatty Acid

Saturated fatty acids have no carbon-carbon double bonds, meaning their carbon chain is "saturated" with hydrogen atoms. They tend to be solid at room temperature and are commonly found in animal fats and some plant oils like coconut oil.[3]

### Unsaturated Fatty Acid

Unsaturated fatty acids contain one or more carbon-carbon double bonds. They are usually liquid at room temperature and found in plant oils, nuts, and fish. Double bonds can be in "cis" (naturally bent) or "trans" (straight, often from processing) configurations.[2][3]

### Trans Fatty Acid

Trans fatty acids have at least one double bond in the "trans" configuration, so the carbon chain is straighter than cis fats. Trans fats are primarily formed during food processing (partial hydrogenation) and increase cardiovascular risk.[1][2]

### Eicosanoid

Eicosanoids are bioactive lipid molecules derived from 20-carbon fatty acids (like arachidonic acid). They act as signaling molecules involved in inflammation, immunity, and many other physiological functions.[2]

### Lipase

Lipase is an enzyme that breaks down fats (triglycerides) into free fatty acids and glycerol during digestion, primarily in the small intestine.[2]

### Bile

Bile is a digestive fluid produced by the liver and stored in the gallbladder. It contains bile salts, which emulsify fats to aid their digestion and absorption.[2]

### Micelle

A micelle is a microscopic structure formed when bile salts surround fat droplets in the intestine, making them more accessible to digestive enzymes and facilitating absorption.[2]

### Chylomicron

A chylomicron is a type of lipoprotein formed in intestinal cells. It transports dietary fats (triglycerides, cholesterol) from the intestine through the lymphatic system into the bloodstream.[2]

### HDL

HDL (High-Density Lipoprotein) is known as "good cholesterol." It transports cholesterol from the blood back to the liver for removal, reducing risk of plaque formation.[3]

### LDL

LDL (Low-Density Lipoprotein) is "bad cholesterol." It carries cholesterol from the liver to tissues, and high levels can lead to cholesterol buildup and increased risk of heart disease.[3]