Introduction to Lipids and Cell Membranes

Practice flashcards covering the characteristics, types, and biological functions of lipids, including saturated/unsaturated fats, cholesterol transport, and membrane structure.

Lipids

A macromolecule that is not a true monomer or polymer because its components associate with each other rather than forming chemical bonds.

Visceral fat

Fat that wraps around internal organs; while some is necessary for protection, excessive amounts are linked to negative health outcomes like heart attacks.

DEXA scan

A diagnostic tool used to show fat composition and the specific areas where fat is located in the body.

Triglyceride

A common type of fat structure consisting of a glycerol molecule and fatty acid tails.

Saturated fat

A fat with no double bonds in its carbon-hydrogen chains, allowing molecules to pack tightly together, typically making them solid at room temperature like steak fat or butter.

Unsaturated fat

A fat that contains double bonds which cause a "kink" or bend in the tail, preventing tight packing and making them liquid at room temperature like olive oil.

Cis bonds

The typical configuration of double bonds in natural unsaturated fats where the atoms are on the same side.

Trans fat

A "fake" fat created by flipping the bond configuration of an unsaturated fat; it remains liquid but tastes like a saturated fat and is difficult for the body to process.

Omega-3s

Oils found in fish that are important for brain health as they help compose the membranes in the brain.

Fat-soluble vitamins

Vitamins that require fat for absorption in the intestines, specifically $\text{Vitamins A, D, E, and K}$.

Arteriosclerosis

Significant damage to the arteries caused by the collection and accumulation of fats, particularly trans fats, which the body cannot easily eliminate.

$\text{HDL}$ (High-Density Lipoprotein)

Known as "good cholesterol," this fatty protein circulates in the blood to scoop out fat collected on arteries and break it down to make hormones.

$\text{LDL}$ (Low-Density Lipoprotein)

Known as "bad cholesterol," this protein delivers fats to the parts of the body that need it for cell membranes, but can lead to artery damage if levels are too high.

Steroids

A form of fat characterized by a basic structure of $4$ fused rings of carbon rather than fatty acid tails.

Phospholipid

The major component of the cell membrane consisting of a glycerol molecule, fatty acid tails, and a phosphate end; it has both hydrophobic and hydrophilic portions.

Hydrophobic

A characteristic of the fatty acid tails of lipids, meaning they "hate water" and repel it.

Hydrophilic

A characteristic of the phosphate head of a phospholipid, meaning it "likes water" and can form bonds with it because it is charged.