Lipids – Biology 1: Chemicals of Life

25 vocabulary flashcards covering key lipid concepts, structures, and functions from the Biology 1 lecture.

Lipids

Greasy, hydrophobic biomolecules composed mainly of non-polar hydrocarbons, insoluble in water but soluble in non-polar or medium-polar solvents.

Triglyceride

A simple lipid made of one glycerol molecule ester-linked to three fatty acids; principal form of fat and oil energy storage.

Fatty Acid

Long hydrocarbon chain with a terminal carboxyl (-COOH) group; carbon skeleton usually even-numbered and may be saturated or unsaturated.

Saturated Fat

Lipid whose fatty acids contain no double bonds; solid at room temperature and common in animal fats like butter.

Unsaturated Fat

Lipid whose fatty acids contain one or more double bonds; liquid at room temperature and typical of plant oils.

Cis Double Bond

Natural configuration of double bonds in unsaturated fatty acids that introduces a bend, preventing tight packing of chains.

Trans Fat

Partially hydrogenated unsaturated fat containing trans double bonds; solidifies oils and mimics the artery-clogging effects of saturated fat.

Hydrogenation

Industrial addition of hydrogen to unsaturated fats, converting some cis bonds to trans bonds and increasing shelf-life.

Ester Bond

Chemical linkage formed between the hydroxyl group of glycerol and the carboxyl group of a fatty acid during lipid synthesis.

Condensation Reaction

Dehydration synthesis that joins molecules (e.g., forming ester bonds in triglycerides) while releasing water.

Glycerol

Three-carbon alcohol that serves as the backbone to which fatty acids and phosphate groups attach in many lipids.

Van der Waals Interactions (in fats)

Weak attractions between closely packed hydrocarbon chains that limit molecular motion and make saturated fats more solid.

Adipose Cells

Specialized mammalian cells that store triglycerides as long-term, energy-rich reserves.

Functions of Triglycerides

Provide concentrated energy, thermal insulation, organ cushioning, waterproofing, and buoyancy due to low density.

Waxes

Lipids of long-chain fatty acids esterified to long-chain alcohols; water-repellent coatings found in plant cuticles and beeswax.

Phospholipid

Complex lipid consisting of glycerol, two fatty acids, a phosphate group, and an additional polar head; key membrane component.

Amphipathic Molecule

Compound possessing both hydrophilic (polar) and hydrophobic (non-polar) regions, enabling interaction with water and lipids.

Phospholipid Bilayer

Double layer formed when phospholipids orient tails inward and heads outward in water; fundamental structure of cell membranes.

Glycolipid

Membrane lipid covalently bonded to a carbohydrate; contributes to membrane stability and facilitates cellular recognition.

Steroid

Lipid with a backbone of four fused carbon rings and various functional groups; lacks fatty acids.

Cholesterol

Major steroid that stabilizes cell membranes and serves as precursor for steroid hormones, bile salts, and vitamin D.

Bile Salts

Cholesterol-derived steroids that emulsify dietary fats during digestion, aiding lipid absorption.

Omega-3 and Omega-6 Fatty Acids

Essential polyunsaturated fatty acids required for brain function and regulation of inflammation.

Liposome

Spherical phospholipid vesicle used as a carrier in drug delivery systems and cosmetic formulations.

Membrane Fluidity

Flexibility of the cell membrane maintained by unsaturated fatty acids, which prevent tight packing of lipid tails at low temperatures.