Chapter 3: Organic Molecules Review

Vocabulary flashcards covering core concepts: polymers and monomers, dehydration synthesis/hydrolysis, carbohydrates (monosaccharides to polysaccharides), nucleic acids (DNA/RNA and nucleotides), proteins (amino acids and protein structure), and lipids (triglycerides, phospholipids, waxes, sterols, trans fats).

Organic molecule

A molecule composed mainly of carbon and hydrogen (often with other elements) and produced by living organisms.

Autotroph

An organism that can form organic molecules from inorganic energy sources (e.g., via photosynthesis).

Heterotroph

An organism that must consume organic molecules produced by other organisms for energy.

Carbohydrates

Organic molecules made of carbon, hydrogen, and oxygen in a roughly 1:2:1 ratio; include simple sugars and complex sugars.

Monosaccharide

A single sugar; the monomer of carbohydrates (e.g., glucose, fructose).

Disaccharide

Two monosaccharides joined together; a simple carbohydrate (e.g., sucrose).

Oligosaccharide

A carbohydrate with roughly 3–100 monosaccharide units.

Polysaccharide

A carbohydrate with more than about 100 monosaccharide units; a complex carbohydrate (e.g., starch, cellulose, glycogen).

Dehydration synthesis / Condensation

A reaction that links monomers by removing water to form a polymer.

Hydrolysis

A reaction that breaks polymers into monomers by adding water.

Nucleic acids

Polymers made of nucleotides that store and transmit genetic information (DNA and RNA).

Nucleotide

Monomer of nucleic acids; composed of a sugar, a phosphate, and a nitrogenous base.

DNA

Deoxyribonucleic acid; stores genetic information; typically double-stranded with a deoxyribose sugar.

RNA

Ribonucleic acid; involved in protein synthesis; typically single-stranded with ribose sugar.

Amino acid

Monomer of proteins; central carbon with an amino group, a carboxyl group, a hydrogen, and a variable R group.

Peptide bond

Bond between adjacent amino acids in a protein chain.

Protein

Polymer of amino acids that performs a vast array of functions in organisms.

Primary structure

Linear sequence of amino acids in a protein.

Secondary structure

Folding patterns such as alpha helices or beta sheets held together by hydrogen bonds.

Tertiary structure

Three-dimensional folding of a protein due to interactions among R groups.

Denaturation

Loss of protein structure and function due to heat, pH change, or other stress.

Prion

Misfolded protein that can induce misfolding of other proteins and cause neurodegenerative diseases.

Lipids

A diverse class of hydrophobic molecules; not always true polymers; include triglycerides, phospholipids, sterols, and waxes.

Triglyceride

Lipid with a glycerol backbone and three fatty acid tails; major form of dietary fat.

Saturated fat

Triglyceride tails with no double bonds; typically solid at room temperature and often animal-derived.

Unsaturated fat

Triglyceride tails with one or more double bonds; typically liquid at room temperature and often plant-derived.

Trans fat

Hydrogenated unsaturated fats that are solid at room temperature; linked to health risks.

Phospholipid

Lipid with a glycerol backbone, a phosphate-containing head, and two fatty acid tails; forms cell membranes; head is hydrophilic, tails are hydrophobic.

Wax

Hydrophobic lipids that provide waterproofing in organisms.

Membrane bilayer

Two-layer arrangement of phospholipids forming cell membranes; heads face water, tails face inward.