Organic Compounds – Lecture Vocabulary

A comprehensive set of vocabulary flashcards covering the key terms and definitions from the lecture on organic compounds, their structures, functions, and biochemical roles.

Organic Chemistry

The study of compounds that contain carbon.

Carbon Backbone

The chain, branch, or ring framework of carbon atoms that forms the structural foundation of organic molecules.

Functional Group

A small cluster of atoms attached to a carbon backbone that determines many properties of an organic molecule.

Hydroxyl Group (–OH)

Functional group found in sugars and alcohols.

Methyl Group (–CH₃)

Functional group common in fats, oils, steroids, and amino acids.

Carboxyl Group (–COOH)

Acidic functional group present in amino acids, sugars, and proteins.

Amino Group (–NH₂)

Basic functional group found in amino acids and proteins.

Phosphate Group (–H₂PO₄)

Functional group present in nucleic acids and ATP.

Macromolecule

A very large organic molecule with a high molecular weight, e.g., proteins or DNA.

Monomer

A single, repeating subunit that can be bonded to form polymers.

Polymer

A molecule made of many repeating monomer subunits.

Polymerization

The process of joining monomers to form a polymer.

Dehydration Synthesis

Reaction that joins monomers by removing –OH and –H, producing water.

Hydrolysis

Reaction that breaks polymers by adding water (–OH and –H).

Carbohydrate

Hydrophilic organic molecule with general formula (CH₂O)n.

Monosaccharide

A single sugar unit such as glucose, galactose, or fructose.

Glucose

Blood sugar; primary energy source for most cells (C₆H₁₂O₆).

Galactose

Monosaccharide converted to glucose for metabolism.

Fructose

Fruit sugar; an isomer of glucose, converted to glucose in the body.

Disaccharide

Sugar composed of two monosaccharides.

Sucrose

Table sugar; glucose + fructose.

Lactose

Milk sugar; glucose + galactose.

Maltose

Malt sugar; glucose + glucose.

Oligosaccharide

Short chain of 3–10 (or a few more) monosaccharides.

Polysaccharide

Long chain of 50 or more monosaccharides.

Glycogen

Animal energy-storage polysaccharide made by liver, muscle, brain, uterus, and vagina.

Starch

Plant energy-storage polysaccharide; only significant digestible polysaccharide in the human diet.

Cellulose

Structural polysaccharide in plant cell walls; dietary fiber for humans.

Conjugated Carbohydrate

A carbohydrate covalently bound to a lipid or protein.

Glycolipid

Conjugated carbohydrate on the external surface of cell membranes.

Glycoprotein

Protein with carbohydrate moiety on the cell surface and in mucus.

Proteoglycan

Large molecule with small core protein and large carbohydrate component; provides gels for lubrication and support.

Lipid

Hydrophobic organic molecule with a high ratio of hydrogen to oxygen.

Fatty Acid

Chain of 4–24 carbons with a carboxyl group on one end and a methyl on the other.

Saturated Fatty Acid

Fatty acid whose carbon atoms are saturated with hydrogen (no C=C double bonds).

Unsaturated Fatty Acid

Fatty acid containing at least one C=C double bond.

Polyunsaturated Fatty Acid

Fatty acid with multiple C=C double bonds.

Essential Fatty Acid

Polyunsaturated fatty acid that must be obtained from the diet.

Triglyceride

Neutral fat composed of three fatty acids bonded to glycerol; functions in energy storage, insulation, and shock absorption.

Phospholipid

Lipid with two fatty acid tails and a phosphate-containing head; main structural component of cell membranes.

Amphiphilic

Having both hydrophobic (tail) and hydrophilic (head) regions, as in phospholipids.

Trans-Fatty Acid

Fatty acid with hydrogen atoms across from each other at a C=C bond; resists breakdown and raises cardiovascular risk.

Cis-Fatty Acid

Fatty acid with hydrogen atoms on the same side of a C=C bond; naturally occurring form.

Eicosanoid

20-carbon lipid derived from arachidonic acid; acts as a local hormone.

Prostaglandin

Type of eicosanoid involved in inflammation, blood clotting, and other processes.

Steroid

Lipid with 17 carbon atoms in four interlocking rings.

Cholesterol

Parent steroid from which other steroids are synthesized; component of cell membranes and nervous tissue.

HDL (High-Density Lipoprotein)

‘Good’ cholesterol particle with low lipid-to-protein ratio; may protect against cardiovascular disease.

LDL (Low-Density Lipoprotein)

‘Bad’ cholesterol particle with high lipid-to-protein ratio; contributes to cardiovascular disease.

Protein

Polymer of amino acids; the most versatile biomolecule.

Amino Acid

Monomer of proteins; contains amino, carboxyl, and variable R group.

Peptide Bond

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

Peptide

Molecule composed of two or more amino acids linked by peptide bonds.

Conformation

Unique three-dimensional shape of a protein required for its function.

Denaturation

Extreme conformational change due to heat or pH that destroys protein function.

Primary Structure

Linear sequence of amino acids in a protein.

Secondary Structure

Alpha helix or beta sheet formed by hydrogen bonding within a protein.

Tertiary Structure

Further folding of a protein into globular or fibrous form due to interactions among R groups and water.

Quaternary Structure

Association of two or more polypeptide chains into a functional protein.

Prosthetic Group

Non-amino acid component covalently bound to a conjugated protein (e.g., heme in hemoglobin).

Enzyme

Protein that acts as a biological catalyst, lowering activation energy.

Substrate

The specific reactant an enzyme acts upon.

Active Site

Region of an enzyme where the substrate binds and reaction occurs.

Activation Energy

Energy required to initiate a chemical reaction; lowered by enzymes.

Metabolic Pathway

Chain of enzymatically catalyzed reactions converting a starting molecule to an end product.

Ligand

Any molecule that reversibly binds to a protein, often a receptor.

Nucleotide

Molecule composed of a nitrogenous base, a sugar, and one or more phosphate groups.

ATP (Adenosine Triphosphate)

Primary energy-transfer nucleotide containing adenine, ribose, and three phosphates.

Nitrogenous Base

Single- or double-ring carbon-nitrogen compound in a nucleotide (e.g., adenine).

DNA (Deoxyribonucleic Acid)

Polymer of nucleotides that stores genetic information and directs protein synthesis.

RNA (Ribonucleic Acid)

Single-stranded nucleic acid (mRNA, rRNA, tRNA) that helps translate genetic instructions into proteins.