AP Biology - Macromolecules, Carbon, Water & Nucleic Acids Vocabulary Flashcards

Vocabulary flashcards covering the properties of water, carbon chemistry, carbohydrates, lipids, proteins, and nucleic acids based on AP Biology lecture materials.

Polar Molecule

A molecule with an uneven distribution of overall charge, such as water, where electrons in polar covalent bonds spend more time near the oxygen atom than the hydrogen atoms.

Cohesion

The phenomenon in which hydrogen bonds collectively hold water molecules together, aiding the transport of water against gravity in plants.

Adhesion

The attraction between different substances, such as between water molecules and plant cell walls.

Surface Tension

A measure of how difficult it is to stretch or break the surface of a liquid, which is unusually high in water due to hydrogen bonding.

Specific Heat

The amount of heat that must be absorbed or lost for $1\,g$ of a substance to change its temperature by $1\,^\circ\text{C}$.

Evaporative Cooling

The process in which the surface of a liquid cools down during evaporation as the molecules with the highest kinetic energy depart.

Solvent

The dissolving agent of a solution.

Solute

The substance that is dissolved in a solution.

Hydration Shell

The sphere of water molecules that surrounds each ion when an ionic compound is dissolved in water.

Hydrophilic

Having an affinity for water.

Hydrophobic

Lacking an affinity for water; nonpolar substances that tend to repel water.

Molarity

A measure of solute concentration in an aqueous solution, defined as the number of moles of solute per liter of solution ($M$).

Acid

A substance that increases the $H^+$ concentration of a solution.

Base

A substance that reduces the $H^+$ concentration of a solution.

Buffer

A substance that minimizes changes in the concentrations of $H^+$ and $OH^-$ in a solution by reversibly combining with hydrogen ions.

Ocean Acidification

The process by which $CO_2$ dissolved in seawater forms carbonic acid ($H_2CO_3$), lowering ocean pH and reducing carbonate ion concentration required for calcification.

Organic Chemistry

The branch of chemistry devoted to the study of carbon-containing compounds, regardless of origin.

Isomers

Compounds that have the same molecular formula but differ in structural arrangement and properties.

Structural Isomers

Isomers that differ in the covalent arrangements of their constituent atoms.

Cis-Trans Isomers

Isomers that have the same covalent bonds but differ in spatial arrangement due to the inflexibility of double bonds.

Enantiomers

Isomers that are non-superimposable mirror images of each other due to an asymmetric carbon atom.

Hydrocarbons

Organic molecules consisting solely of carbon and hydrogen atoms.

Functional Groups

Specific chemical groups attached to a carbon skeleton that are directly involved in chemical reactions and give organic molecules unique properties.

Adenosine Triphosphate (ATP)

An organic phosphate molecule consisting of adenosine attached to three phosphate groups, serving as the principal energy currency of the cell.

Polymer

A long molecule consisting of many similar or identical building blocks connected by covalent bonds.

Monomer

The repeating subunit that serves as the building block of a polymer.

Dehydration Reaction

A chemical reaction in which two molecules become covalently bonded to each other with the removal of a water molecule.

Hydrolysis

A chemical reaction that breaks covalent bonds between monomers by the addition of a water molecule.

Monosaccharide

The simplest carbohydrate monomer (simple sugar), with molecular formulas generally consisting of multiples of $CH_2O$.

Glycosidic Linkage

A covalent bond formed between two monosaccharides by a dehydration reaction.

Starch

A storage polysaccharide in plants consisting entirely of glucose monomers linked by $\alpha$ glycosidic bonds.

Glycogen

An extensively branched glucose storage polysaccharide found in liver and muscle tissue of animals.

Cellulose

A structural polysaccharide consisting of glucose monomers linked by $\beta$ 1-4 glycosidic linkages, serving as the main component of plant cell walls.

Chitin

A structural polysaccharide found in the exoskeleton of arthropods and the cell walls of many fungi.

Triacylglycerol

A fat molecule composed of three fatty acids linked to one glycerol molecule by ester linkages.

Ester Linkage

The covalent bond formed between a hydroxyl group of glycerol and a carboxyl group of a fatty acid during dehydration synthesis.

Saturated Fatty Acid

A fatty acid in which all carbons in the hydrocarbon tail are connected by single bonds, maximizing hydrogen content.

Unsaturated Fatty Acid

A fatty acid possessing one or more double bonds between carbon atoms in its hydrocarbon chain, introducing kinks.

Phospholipid

A lipid made of glycerol joined to two fatty acids and a phosphate group, forming amphipathic molecules that form cell membrane bilayers.

Steroid

A type of lipid characterized by a carbon skeleton consisting of four fused carbon rings.

Cholesterol

A steroid that forms an essential component of animal cell membranes and acts as a precursor for hormone synthesis.

Amino Acid

An organic molecule possessing a central $\alpha$ carbon bound to a hydrogen atom, a carboxyl group, an amino group, and a variable R group.

Peptide Bond

The covalent bond between the carboxyl group of one amino acid and the amino group of another, formed by a dehydration reaction.

Polypeptide

A polymer of amino acids linked together by peptide bonds.

Protein

A biologically functional molecule consisting of one or more polypeptides folded into a specific three-dimensional conformation.

Primary Structure

The specific linear sequence of amino acids in a polypeptide chain.

Secondary Structure

Local coils and folds in a polypeptide backbone resulting from hydrogen bonding, including $\alpha$-helices and $\beta$-pleated sheets.

Tertiary Structure

The overall three-dimensional shape of a single polypeptide chain, stabilized by side chain (R group) interactions.

Quaternary Structure

The overall protein structure resulting from the aggregation of two or more individual polypeptide subunits.

Disulfide Bridge

A strong covalent bond formed between two cysteine monomers when their sulfhydryl groups react, reinforcing protein tertiary structure.

Denaturation

A process in which a protein unravels and loses its native structure due to environmental factors such as changes in pH, temperature, or salt concentration.

Gene

A discrete unit of hereditary information consisting of a specific sequence of nucleotides in DNA (or RNA, in some viruses).

Gene Expression

The multi-step process by which DNA directs its own replication and mRNA synthesis, which in turn directs protein synthesis.

Deoxyribonucleic Acid (DNA)

A nucleic acid molecule, usually double-stranded, that contains deoxyribose sugar and stores genetic information.

Ribonucleic Acid (RNA)

A nucleic acid molecule, usually single-stranded, containing ribose sugar and functions in gene expression.

Nucleotide

The monomer of a polynucleotide, consisting of a five-carbon pentose sugar, a nitrogenous base, and one or more phosphate groups.

Nucleoside

The portion of a nucleotide consisting of a nitrogenous base bound to a pentose sugar, excluding any phosphate groups.

Pyrimidines

Nitrogenous bases consisting of a single six-membered ring, including cytosine (C), thymine (T), and uracil (U).

Purines

Nitrogenous bases consisting of a six-membered ring fused to a five-membered ring, including adenine (A) and guanine (G).

Phosphodiester Linkage

A covalent bond consisting of a phosphate group linking the sugars of two adjacent nucleotides in a polynucleotide chain.

Antiparallel

The structural arrangement of the two sugar-phosphate backbones in a DNA double helix, running in opposite $5' \rightarrow 3'$ directions.

Genomics

The systematic study and comparison of whole sets of genes and their interactions within and between species.

Proteomics

The systematic study of full sets of proteins and their functional properties.

Bioinformatics

The application of computational tools and software to analyze and process large biological datasets.