Organic Molecules and Macromolecules Flashcards

Vocabulary flashcards covering organic chemistry principles, functional groups, isomers, polymerization reactions, carbohydrates, lipids, proteins, enzymes, and nucleic acids based on the lecture transcript.

Organic Chemistry

The branch of chemistry devoted to carbon compounds.

Carbon

The chemical element whose properties are fundamental to forming biologically important organic molecules, capable of forming up to four covalent bonds.

Functional Groups

Groups of atoms with characteristic chemical structures and properties that bond to carbon in organic molecules.

Amino Group

A weakly basic functional group ($\text{-NH}_2$) that can accept $\text{H}^+$, is polar, and forms part of peptide bonds in amino acids and proteins.

Carbonyl Group

A polar, highly chemically reactive functional group ($\text{-CO}$) found in ketones, aldehydes, steroids, waxes, and proteins that forms hydrogen bonds.

Carboxyl Group

An acidic functional group ($\text{-COOH}$) that gives up $\text{H}^+$ in water and forms part of peptide bonds in amino acids and fatty acids.

Hydroxyl Group

A polar functional group ($\text{-OH}$) that forms hydrogen bonds with water; found in steroids, alcohol, carbohydrates, and some amino acids.

Methyl Group

A nonpolar functional group ($\text{-CH}_3$) that may be attached to DNA, proteins, and carbohydrates.

Phosphate Group

A polar, weakly acidic functional group ($\text{-PO}_4^{2-}$) that is negatively charged at typical pH of living organisms; found in nucleic acids, ATP, and phospholipids.

Sulfhydryl Group

A polar functional group ($\text{-SH}$) found in proteins containing cysteine that forms disulfide bridges.

Isomers

Organic molecules that have identical molecular formulas but a different arrangement of atoms.

Structural Isomers

Isomers that differ in the order in which their constituent atoms are attached.

Stereoisomers

Isomers with identical bonding relationships whose atoms differ in their spatial positioning.

Geometric Isomers

Stereoisomers (cis/trans isomers) that differ in spatial positioning of atoms around a double bond.

Enantiomers

Stereoisomers that exist as non-superimposable mirror images of each other (chiral molecules).

Polymers

Large biological molecules constructed by linking together many identical or similar subunits called monomers.

Monomers

Small, repeating organic subunits that polymerize to form polymers.

Dehydration Synthesis Reaction

A chemical reaction that synthesizes polymers from monomers by removing a molecule of water ($\text{H}_2\text{O}$).

Hydrolysis Reaction

A chemical reaction that depolymerizes or breaks down polymers into monomers by adding a molecule of water ($\text{H}_2\text{O}$).

Monosaccharides

Single sugar molecules consisting of linked carbons and hydrogens that serve as the monomers of carbohydrates.

Glycosidic Bond

The covalent bond formed between two monosaccharides joined by a dehydration reaction.

Starch

A plant storage polysaccharide composed of $\alpha\text{-glucose}$ monomers, existing as unbranched amylose and branched amylopectin.

Glycogen

A highly branched animal storage polysaccharide composed of $\alpha\text{-glucose}$ monomers linked by $\alpha\text{-1-4}$ and $\alpha\text{-1-6}$ linkages.

Cellulose

An unbranched structural polysaccharide in plant cell walls composed of long chains of $\beta\text{-glucose}$ molecules joined by $\beta\text{-1-4}$ linkages.

Chitin

A structural polysaccharide found in animal exoskeletons and fungal cell walls composed of $N\text{-acetylglucosamine}$ monomers.

Fatty Acids

Hydrocarbon chains of varying length terminating in a carboxyl group that serve as basic subunits of lipids.

Saturated Fatty Acid

A fatty acid with no double bonds between carbon atoms, resulting in a linear structure that packs tightly and is solid at room temperature.

Unsaturated Fatty Acid

A fatty acid containing one or more double bonds that introduce kinks in the hydrocarbon chain, preventing tight packing and causing it to be liquid at room temperature.

Cis-Fats

Naturally occurring unsaturated fats where the hydrocarbon chain is in the cis conformation across double bonds.

Trans-Fats

Artificially manufactured unsaturated fats where the hydrocarbon chain is in the trans conformation across double bonds.

Triglycerides

Pseudo-polymers formed by joining three fatty acid molecules to a single glycerol backbone via ester bonds in dehydration reactions.

Ester Bond

The covalent bond formed between the hydroxyl group of glycerol and the carboxyl group of a fatty acid.

Phospholipids

Amphipathic lipid molecules consisting of a polar hydrophilic head and two nonpolar hydrophobic fatty acid tails, forming cell membrane bilayers.

Steroids

Lipids defined by a structure of four fused carbon rings, including cholesterol, estradiol, and testosterone.

Waxes

Lipids composed of fatty acids bonded to long hydrocarbon chains, used by organisms for waterproofing and protection.

Amino Acids

The building blocks of proteins, consisting of a central $\alpha\text{-carbon}$ bonded to an amino group, a carboxyl group, a hydrogen atom, and a variable side chain ($\text{R}$ group).

Peptide Bond

The covalent bond formed between the carboxyl carbon of one amino acid and the amino nitrogen of another during protein synthesis.

Polypeptide

A linear sequence of amino acids linked together by peptide bonds, serving as the structural unit of a protein.

Primary Structure

The linear sequence of amino acids in a polypeptide chain.

Secondary Structure

Conformations within a polypeptide, such as $\alpha\text{-helices}$ and $\beta\text{-pleated sheets}$, held together by hydrogen bonds between backbone atoms.

Tertiary Structure

The overall three-dimensional shape of a single polypeptide chain formed by folding secondary structures and connecting coil regions.

Quaternary Structure

The functional protein complex formed when two or more polypeptide subunits bind to each other.

Disulfide Bridge

A covalent bond formed between the sulfhydryl ($\text{-SH}$) groups of two cysteine residues within a protein.

Denaturation

A process in which a protein loses its specific three-dimensional shape and biological activity due to heat, pH changes, or chemicals.

Chaperone Proteins

Proteins that assist misfolded proteins in correctly refolding into their functional three-dimensional structures using ATP.

Enzyme

A protein that acts as an organic catalyst to accelerate a chemical reaction without being consumed, by lowering its activation energy ($E_a$).

Ribozyme

An RNA molecule that exhibits enzymatic activity.

Induced Fit Model

The model describing how an enzyme undergoes a conformational change upon substrate binding at the active site to form the enzyme-substrate complex.

Competitive Inhibitor

A reversible inhibitor that binds directly to the active site of an enzyme, competing with the substrate.

Noncompetitive Inhibitor

A reversible inhibitor that binds to an allosteric site on an enzyme, altering its shape so that it cannot bind substrate effectively.

Nucleotides

The monomeric units of nucleic acids, each composed of a pentose sugar, a phosphate group, and a nitrogenous base.

Phosphodiester Bond

The covalent bond linking nucleotides, formed between the $3'$ hydroxyl group of one pentose sugar and the $5'$ phosphate group of the adjacent sugar.

Purines

Double-ring nitrogenous bases found in nucleic acids, consisting of Adenine and Guanine.

Pyrimidines

Single-ring nitrogenous bases found in nucleic acids, consisting of Cytosine, Thymine (DNA only), and Uracil (RNA only).

Deoxyribonucleic Acid (DNA)

A double-stranded, antiparallel nucleic acid containing deoxyribose sugar and thymine that stores genetic information in units called genes.

Ribonucleic Acid (RNA)

A typically single-stranded nucleic acid containing ribose sugar and uracil that provides access to genetic information for protein expression.