Lipids & Fats (FN 2070)

Flashcards covering key vocabulary related to lipids and fats, including their structure, types, functions, digestion, absorption, transport, and health implications.

Lipids (Fats)

A major source of energy, a component of cells and tissues, helps absorb vitamins, and can be converted into other molecules.

Fatty Acid

A molecule made up of a carboxylic group and a hydrocarbon chain.

Saturated Fatty Acid

A fatty acid with no double bonds in its structure, typically solid at room temperature.

Unsaturated Fatty Acid

A fatty acid with one or more double bonds in its structure, typically liquid at room temperature and often has a bent or kinked structure due to cis double bonds.

Short-chain fatty acids

Fatty acids consisting of 5 or fewer carbons.

Medium-chain fatty acids

Fatty acids consisting of 6-12 carbons.

Long-chain fatty acids

Fatty acids consisting of 13-21 carbons.

Triglyceride

A lipid composed of a glycerol molecule attached to three fatty acid chains; the main form of fat stored in the body.

Phospholipid

A type of lipid characterized by a hydrophilic (water-attracting) head and two hydrophobic (water-repelling) fatty acid tails; a key component of cell membranes.

Amphipathic

A molecule that possesses both hydrophobic and hydrophilic properties, such as phospholipids.

Steroid

A type of lipid characterized by a distinct four-ring structure, such as cholesterol.

Cholesterol

A type of steroid that is a component of cell membranes and a precursor for hormones and vitamin D.

Essential Fatty Acids (EFA)

Fatty acids, specifically Omega-3 and Omega-6, that cannot be synthesized by the body and must be obtained from the diet.

Eicosanoids

A family of lipid-based biological signaling molecules made from essential fatty acids (omega 3 & 6) that act as short-range messengers, regulating physiological responses like inflammation, pain, and blood flow.

Omega-6 fats

Essential fatty acids that make compounds tending to spark or promote inflammation ('fire starters').

Omega-3 fats

Essential fatty acids that make compounds tending to calm inflammation ('firefighters') partly by blocking COX-2.

Lingual lipase

An enzyme in the mouth that begins the digestion of fats.

Gastric lipase

An enzyme in the stomach that breaks down short- and medium-chain fatty acids.

Cholecystokinin (CCK)

A hormone released by the small intestine in response to the presence of fat, which stimulates the release of bile from the liver/gallbladder and pancreatic lipase from the pancreas.

Bile

A fluid produced by the liver and stored in the gallbladder that emulsifies fats into micelles in the small intestine, increasing their surface area for enzyme action.

Pancreatic lipase

An enzyme released from the pancreas into the small intestine that breaks down triglyceride bonds during fat digestion.

Micelle

Small, emulsified droplets formed during fat digestion, consisting of a hydrophobic core of digested lipids and a hydrophilic shell, which transport lipids to enterocytes.

Enterocyte

An intestinal cell where digested lipids delivered by micelles are absorbed and reassembled into triglycerides.

Chylomicron

A large lipoprotein formed within enterocytes that packages reassembled triglycerides and other fat-soluble substances for transport into the lymphatic system and then the bloodstream.

Lacteal

Special lymphatic vessels located in the villi of the small intestine that absorb dietary lipids, specifically chylomicrons, which are too large to enter blood capillaries directly.

Lipoproteins

General transport vehicles for moving water-insoluble lipids (cholesterol, triglycerides, phospholipids, proteins) around the body within the bloodstream.

Low-density lipoprotein (LDL)

Often called 'bad cholesterol,' these lipoproteins deliver cholesterol to cells; high levels can lead to plaque buildup in arteries.

High-density lipoprotein (HDL)

Often called 'good cholesterol,' these lipoproteins transport excess cholesterol from cells back to the liver for excretion, a process known as reverse cholesterol transport.

Atherosclerosis

A disease characterized by the deposition of plaque (made of cholesterol-rich lipoproteins, foam cells) within the walls of blood vessels, leading to the narrowing and hardening of arteries.