Organic Molecules Notes - Vocabulary Flashcards

Vocabulary flashcards covering key terms and definitions related to organic molecules, their functional groups, and the four major biomolecule families.

Water

Best solvent; forms hydrogen bonds; stable; polar covalent bonds; absorbs heat; original source of hydrogen and oxygen.

Carbon

Base of all organic compounds; tetravalent; can form 4 covalent bonds; bonds to itself and to other elements to build carbon skeletons.

Carbon skeleton

The chain or ring framework of carbon atoms in an organic molecule; can be unbranched, branched, contain double bonds, or form rings.

Organic molecules

Molecules composed mainly of carbon with hydrogen; two or more carbons bonded; may have hydrogens attached; contain functional groups; determine properties.

Functional group

A specific arrangement of atoms that imparts characteristic properties to organic molecules (examples: -OH, -SH, C=O, -COOH, PO4, -NH2).

Hydroxyl group (-OH)

A functional group that dissolves well in water; found in alcohols.

Sulfhydryl group (-SH)

A functional group; also called a thiol; tends to be hydrophilic.

Carbonyl group (C=O)

A functional group; hydrophilic; includes aldehydes and ketones.

Carboxyl group (COOH)

A functional group; hydrophilic; acids (donate H+ in solution).

Phosphate group (PO4)

A hydrophilic functional group; acts as acids; often involved in energy transfer and signaling.

Amino group (-NH2)

A hydrophilic functional group; acts as a base.

Dehydration synthesis

Condensation reaction; two molecules join with removal of a water molecule to form a larger molecule (e.g., disaccharides, peptide bonds).

Monosaccharide

Single sugar units; building blocks for larger carbohydrates (examples: glucose, fructose, ribose, deoxyribose).

Glucose

A monosaccharide; major energy source for cells.

Fructose

A monosaccharide; simple sugar found in fruits and honey.

Ribose

A five-carbon sugar in RNA.

Deoxyribose

A five-carbon sugar in DNA; lacks one oxygen compared to ribose.

Disaccharide

Two monosaccharides joined by a glycosidic bond; formed via dehydration synthesis (examples: sucrose, lactose, maltose).

Sucrose

Disaccharide composed of glucose + fructose; table sugar.

Lactose

Disaccharide composed of glucose + galactose; milk sugar.

Maltose

Disaccharide composed of two glucose units; product of starch digestion.

Polysaccharide

Many monosaccharides linked together; used for energy storage or structure (examples: glycogen, starch, cellulose, chitin).

Glycogen

Polysaccharide; animal storage form of glucose; highly branched.

Starch

Polysaccharide; plant storage form of glucose.

Cellulose

Polysaccharide; plant structural carbohydrate; beta-1,4 linkages; not digestible by humans.

Chitin

Polysaccharide; structural carbohydrate in arthropod exoskeletons and fungi.

Starch test (iodine)

Iodine test turns blue-black in the presence of starch; positive test indicates starch presence.

Lipids

Class of C, H, O compounds with no fixed H:O ratio; includes triglycerides, phospholipids, steroids; hydrophobic; energy storage and structure.

Triglyceride

Three fatty acids esterified to glycerol; primary form of fat for energy storage; formed by dehydration synthesis.

Glycerol

Backbone molecule to which fatty acids attach in triglycerides.

Fatty acid

Hydrocarbon chain with a carboxyl group; can be saturated or unsaturated.

Saturated fatty acid

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

Unsaturated fatty acid

Fatty acid with one or more double bonds; often cis; typically liquid at room temperature.

Trans fatty acid

Fatty acid with trans double bonds; produced by hydrogenation; associated with negative health effects.

Phospholipid

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

Steroid

Lipids with four fused rings; cholesterol; precursors to steroid hormones (e.g., progesterone, testosterone, estradiol).

Cholesterol

A common animal sterol; component of cell membranes and precursor to steroid hormones.

Proteins

Macromolecules containing C, H, O, N (and sometimes S); built from amino acids; essential for structure, enzymes, transport, and signaling.

Amino acid

Building blocks of proteins; contain amino group, carboxyl group, and a side chain (R); about 20 different kinds; can be polar, nonpolar, acidic, or basic.

Peptide bond

Covalent bond joining amino acids; formed by condensation (water is released).

Protein structure levels (primary to quaternary)

Primary: sequence of amino acids; Secondary: alpha-helix or beta-sheet; Tertiary: 3D folding; Quaternary: multiple polypeptide chains.

Denaturation

Unraveling of a protein due to heat or extreme pH, leading to loss of structure and function.

Nucleic acids

Class of biomolecules containing CHONP; store and transmit genetic information; made of nucleotides.

Nucleotide

Monomer of nucleic acids; consists of a sugar (ribose or deoxyribose), a phosphate group, and a nitrogenous base.

Deoxyribose

Five-carbon sugar in DNA.

Ribose

Five-carbon sugar in RNA.

DNA (Deoxyribonucleic acid)

Hereditary material; double-stranded; uses deoxyribose; bases A, T, G, C.

RNA (Ribonucleic acid)

Single-stranded nucleic acid; uses ribose; bases A, U, G, C; involved in protein synthesis.

Adenine, Thymine, Cytosine, Guanine, Uracil

Nitrogenous bases of nucleic acids; A-T and G-C pair in DNA; A-U and G-C pair in RNA.

Base pairing

A pairs with T (DNA) or U (RNA); G pairs with C; holds the two strands of DNA together.

Transcription

Process by which DNA is used as a template to synthesize mRNA in the nucleus.

Translation

Process by which the mRNA code is read by ribosomes to assemble amino acids into a polypeptide.