B1.1-Carbohydrates-and-Lipids

Macromolecules

Large biological molecules made from many smaller units (e.g., carbohydrates, lipids, proteins, nucleic acids).

Monomers

Small molecules that can join together to form polymers.

Polymers

Large molecules made by linking many monomers together.

Covalent Bonds

Strong chemical bonds formed when atoms share electrons; hold biological molecules together.

Organic Compound

A carbon-containing compound (excluding CO₂ and carbonates) found in living organisms.

Inorganic Compound

Compounds of non-biological origin, such as water or mineral salts.

Carbohydrates

Organic compounds made of carbon, hydrogen, and oxygen; used for energy, storage, and structure (e.g., sugars, starch, cellulose).

Monosaccharide

A single sugar molecule that cannot be hydrolysed further (e.g., glucose, fructose).

Disaccharide

A sugar made of two monosaccharides joined by a condensation reaction (e.g., sucrose).

Polysaccharide

Large carbohydrates formed from many monosaccharides joined together (e.g., starch, glycogen, cellulose).

Pentose Sugars

Monosaccharides with 5 carbon atoms (e.g., ribose).

Hexose Sugars

Monosaccharides with 6 carbon atoms (e.g., glucose).

Glycosidic Bond

The covalent bond that joins monosaccharides together in carbohydrates.

Starch

A plant storage polysaccharide made of amylose and amylopectin.

Amylose

A polysaccharide of α-glucose with 1–4 glycosidic bonds; forms long, unbranched chains.

Amylopectin

A highly branched polysaccharide of α-glucose; allows rapid glucose release in plants.

Glycogen

A highly branched polysaccharide used as an energy store in animals (liver and muscles).

Cellulose

A structural polysaccharide made of β-glucose; forms plant cell walls.

Cellulose Microfibrils

Bundles of cellulose molecules that provide high tensile strength to plant cell walls.

Storage Carbohydrates

Carbohydrates used to store energy (e.g., starch in plants, glycogen in animals).

Structural Polysaccharide

A carbohydrate used for support and structure (e.g., cellulose, chitin).

Condensation Reaction

A reaction that joins two molecules together using a covalent bond and releases water.

Hydrolysis Reaction

A reaction that breaks a bond using water, splitting polymers into monomers.

Glycoproteins

Proteins with carbohydrate chains attached; involved in cell recognition and signaling.

Glycolipids

Carbohydrates covalently bonded to lipids; important in cell membranes and recognition.

Antigens

Molecules (often glycoproteins) that trigger an immune response.

Lipids

A group of organic molecules including fats, oils, waxes, and steroids; insoluble in water.

Triglyceride

A lipid made of one glycerol molecule bonded to three fatty acids.

Fatty Acids

Long hydrocarbon chains with a carboxyl group; building blocks of lipids.

Fats

Triglycerides that are solid at room temperature (usually saturated).

Oils

Triglycerides that are liquid at room temperature (usually unsaturated).

Saturated Fatty Acids

Fatty acids with no double bonds; carbon atoms are fully bonded to hydrogen.

Unsaturated Fatty Acids

Fatty acids containing one or more double bonds.

Monounsaturated Fatty Acids

Fatty acids with one double bond.

Polyunsaturated Fatty Acids

Fatty acids with two or more double bonds.

Cis

Configuration where hydrogen atoms are on the same side of a double bond, causing a bend.

Trans

Configuration where hydrogen atoms are on opposite sides of a double bond; straight chain.

Steroids

Lipids with four fused carbon rings (e.g., cholesterol, hormones).

Sterols

A subgroup of steroids, including cholesterol and plant sterols.

Cholesterol

A sterol found in animal cell membranes; precursor to steroid hormones and vitamin D.

Isomer

Molecules with the same chemical formula but different structural arrangements.

Polypeptides

Polymers of amino acids (proteins).

Nucleic Acids

Macromolecules (DNA and RNA) that store genetic information.

carboxyl group

a carbon atom double-bonded to one oxygen (carbonyl) and single-bonded to a hydroxyl group (–OH)