Carbohydrates & Lipids Fundamentals

Vocabulary flashcards covering key terms and definitions about carbohydrates (starch, maltose) and lipids (triglycerides, phospholipids, steroids) from the lecture notes.

Starch (coiled structure)

The α-glucose polymer is helically coiled to make the molecule compact, enabling efficient energy storage in cells.

Hydrolysis

A reaction that splits a larger molecule into smaller units by adding water; e.g., starch → α-glucose or triglyceride → glycerol + fatty acids.

Condensation Reaction

A chemical process that joins two molecules with the removal of a water molecule; forms bonds such as glycosidic or ester linkages.

α-Glucose

A six-carbon monosaccharide that serves as the primary substrate for cellular respiration and building block of starch and maltose.

α-1,4 Glycosidic Bond

The covalent linkage between C1 of one α-glucose and C4 of another, found in maltose and amylose.

Maltose

A disaccharide produced from two α-glucose units via condensation; can be hydrolysed by maltase into two glucose molecules.

Maltase

An enzyme that catalyses both the formation and hydrolysis of maltose by acting on α-1,4 glycosidic bonds.

Lipid

A water-insoluble, organic compound containing C, H, and O with proportionally less oxygen than carbohydrates; soluble in organic solvents.

Triglyceride (Triacylglycerol)

A lipid formed by condensation of three fatty acids with one glycerol, joined by ester bonds; primary form of long-term energy storage.

Glycerol

A three-carbon alcohol, each carbon bearing a hydroxyl group, serving as the backbone of triglycerides and phospholipids.

Fatty Acid

A long hydrocarbon chain (typically 16–18 C) with a terminal carboxyl group; can be saturated or unsaturated.

Saturated Fatty Acid

Fatty acid whose hydrocarbon chain contains no C=C double bonds; fully hydrogenated, solid at room temperature, increases LDL levels.

Unsaturated Fatty Acid

Fatty acid with one or more C=C double bonds; chain is not fully hydrogenated, liquid at room temperature, lowers LDL levels.

Phospholipid

A lipid containing a phosphate group, glycerol, and two fatty acids; amphipathic molecule forming the bilayer of cell membranes.

Hydrophilic Head (of phospholipid)

The phosphate-containing, polar region of a phospholipid that interacts with water.

Hydrophobic Tail (of phospholipid)

The non-polar fatty acid chains of a phospholipid that avoid water and face inward in lipid bilayers.

Steroid

A lipid characterized by a backbone of four fused carbon rings (three hexagons and one pentagon); includes cholesterol and steroid hormones.

Cholesterol

A 27-carbon steroid with a single hydroxyl group; amphipathic, modulates membrane fluidity and is a precursor for bile salts, vitamin D, and steroid hormones.

Myelin Sheath

Lipid-rich layer (containing cholesterol and phospholipids) that insulates axons and speeds up nerve impulse transmission.

Bile Salt

Cholesterol-derived molecule that emulsifies dietary fats in the small intestine to aid digestion.

Vitamin D

A sterol produced from cholesterol; essential for calcium absorption and healthy bones and teeth.

Adipose Tissue

Connective tissue that stores triglycerides, acting as an energy reserve, heat insulator, and cushion for organs.

Metabolic Water

Water generated during the oxidation of lipids and carbohydrates, vital for desert animals like kangaroo rats.

Low-Density Lipoprotein (LDL)

Particle that transports cholesterol in blood; levels increase with saturated fats and decrease with unsaturated fats.

Wax Cuticle

Hydrophobic lipid layer covering plant epidermis, reducing water loss and blocking pathogen entry.