Biological Macromolecules – Lecture 04

Vocabulary flashcards summarizing key terms and definitions from Lecture 04 on Biological Macromolecules.

Macromolecule

A very large molecule formed by the assembly of many smaller molecules (monomers); includes carbohydrates, proteins, lipids, and nucleic acids.

Monomer

A small building-block molecule that can bond repeatedly with others to form a polymer.

Polymer

A macromolecule composed of repeating monomer units linked together.

Polymerization

The chemical process that links monomers to form a polymer.

Condensation reaction

Reaction that joins two molecules into one while removing a small molecule, often water; also called dehydration synthesis.

Hydrolysis

The reverse of condensation; breaks polymers into monomers by adding water and releases energy.

Carbohydrate

Organic compound with general formula (CH₂O)ₙ used for energy and structural roles; includes sugars and starches.

Monosaccharide

The simplest carbohydrate; a single sugar unit such as glucose.

Disaccharide

A sugar formed by two linked monosaccharides, e.g., sucrose.

Polysaccharide

A carbohydrate polymer made of many monosaccharide units, e.g., starch.

Glucose

Six-carbon monosaccharide (C₆H₁₂O₆); primary cellular energy source.

Sucrose

Disaccharide of glucose + fructose; common table sugar.

Lactose

Disaccharide of glucose + galactose; milk sugar.

Maltose

Disaccharide of two glucose units; found in germinating seeds.

Starch

Plant polysaccharide used for energy storage; digestible by animals.

Glycogen

Animal storage polysaccharide located chiefly in liver and muscle.

Cellulose

Structural polysaccharide in plant cell walls; indigestible to animals.

Chitin

Nitrogen-containing polysaccharide forming insect and arthropod exoskeletons.

Simple carbohydrate

Mono- or disaccharide that is rapidly broken down to provide instant energy.

Complex carbohydrate

Polysaccharide that supplies a sustained energy release upon digestion.

Protein

Polymer of amino acids with diverse structural, enzymatic, and regulatory functions.

Amino acid

Monomer containing an amine group, carboxyl group, and variable R group; builds proteins.

Essential amino acid

Amino acid that cannot be synthesized by the body and must be obtained from diet.

Non-essential amino acid

Amino acid that the body can synthesize on its own.

Peptide bond

Covalent bond linking the carboxyl group of one amino acid to the amine group of another.

Primary structure

Linear sequence of amino acids in a protein.

Secondary structure

Localized folding of a protein into α-helices or β-pleated sheets.

Tertiary structure

Overall three-dimensional shape of a single polypeptide chain.

Quaternary structure

Association of multiple polypeptide chains into one functional protein.

Enzyme

Protein that acts as a biological catalyst to speed up chemical reactions.

Lipid

Hydrophobic organic molecule (mainly C and H) including fats, oils, phospholipids, and steroids.

Fatty acid

Long hydrocarbon chain with a terminal carboxyl group; component of many lipids.

Glycerol

Three-carbon alcohol that forms the backbone of triglycerides and phospholipids.

Triglyceride

Lipid consisting of glycerol bound to three fatty acids; major energy storage form.

Saturated fatty acid

Fatty acid with no carbon–carbon double bonds; typically solid at room temperature.

Unsaturated fatty acid

Fatty acid with one or more double bonds; usually liquid at room temperature.

Phospholipid

Lipid with two fatty acids and a phosphate group; amphipathic component of cell membranes.

Lipid bilayer

Double layer of phospholipids that forms the structural basis of cell membranes.

Steroid

Lipid characterized by four fused carbon rings; includes cholesterol and hormones.

Cholesterol

Steroid that stabilizes cell membranes and serves as precursor for steroid hormones.

Essential fatty acid

Fatty acid the body cannot synthesize and must obtain through diet.

Nucleic acid

Polymer of nucleotides that stores or transmits genetic information (DNA or RNA).

Nucleotide

Monomer composed of a phosphate group, pentose sugar, and nitrogenous base.

DNA (Deoxyribonucleic acid)

Double-helical nucleic acid that stores long-term genetic information.

RNA (Ribonucleic acid)

Single-stranded nucleic acid that helps translate genetic code into proteins.

Adenine

Purine nitrogenous base in DNA and RNA; pairs with thymine in DNA or uracil in RNA.

Thymine

Pyrimidine base found only in DNA; pairs with adenine.

Uracil

Pyrimidine base found only in RNA; pairs with adenine.

Cytosine

Pyrimidine base present in DNA and RNA; pairs with guanine.

Guanine

Purine base present in DNA and RNA; pairs with cytosine.