AP Biology: Water, Functional Groups, and Macromolecules Vocabulary

Vocabulary practice flashcards covering water properties, functional groups, carbohydrates, lipids, and protein structure levels based on lecture notes.

Polar Molecule

A molecule, such as water, with positive ($+$) and negative ($-$) poles that allows it to pull other molecules apart and dissolve them.

Hydrogen Bond

A weak chemical attraction that attracts water molecules to each other.

Surface Tension

A measure of how difficult it is to stretch or break the surface of a liquid, allowing organisms like water striders to stay on water.

Cohesion

The property of water being attracted to other water molecules, causing drops on surfaces to move towards each other.

Adhesion

The property of water molecules being attracted to other non-water surfaces.

Capillary Action

A combination of cohesion and adhesion that allows water to move up small tubes.

High Specific Heat

The property of water that allows it to resist changes in temperature.

Evaporative Cooling

The process where water releases heat as it evaporates from a surface, such as during sweating.

Functional Groups

Regions of molecules most commonly involved in chemical reactions that are hydrophilic, increase the solubility of compounds, and give molecules unique properties.

Hydroxyl Group

A polar functional group called alcohols ending in '-ol' that helps dissolve organic compounds like sugar in water.

Carbonyl Group

A functional group containing a double bond where the bond location determines the compound, requiring a carbon chain of at least 3.

Carboxyl Group

A functional group that forms organic carboxylic acids when its $H^+$ dissociates due to the pull from both oxygen atoms.

Amino Group

A functional group called amines that picks up $H^+$ from the surrounding solution to act like a base and acquire a positive ($+$) charge.

Sulfhydryl Group

A functional group ($-SH$) chemically similar to oxygen, found in organisms such as skunks and millipedes.

Phosphate Group

A functional group formed by detached phosphoric acid covalently attached by 1 oxygen to a carbon chain, which can transfer energy between organic molecules.

Methyl Group

A non-polar functional group found in proteins and nucleic acids (DNA).

Methylation

A key chemical process involving methyl groups that functions in turning genes on and off.

Monomer

Individual building block parts that link together to make up a polymer.

Polymer

A large molecule composed of many monomers joined together.

Dehydration Synthesis

The reaction that links monomers together by removing a water molecule.

Hydrolysis

The reaction that undoes dehydration synthesis by breaking bonds with the addition of water, releasing energy.

Carbohydrates

Molecules containing $CHO$ with a hydroxyl group attached to each carbon except one, where monomers recognize each other by shape.

Monosaccharide

Single sugar units with a sweet taste that serve as major nutrients for cells (such as glucose) and are used for synthesis of other organic molecules.

Disaccharide

A molecule consisting of two monosaccharides linked together.

Glycosidic Linkage

A covalent bond formed by condensation between two sugar monomers, such as glucose and glucose forming maltose.

Polysaccharide

A long chain of linked sugar monomers used for energy storage (starch/glycogen) or structural support (cellulose/chitin).

Lipids

Mostly hydrophobic hydrocarbon molecules with $C-H$ bonds that are soluble in nonpolar solvents, including fats, oils, and waxes.

Ester Linkage

The covalent bond formed between carboxyl and hydroxyl groups to connect glycerol and fatty acids in a triglyceride.

Saturated Fats

Fats saturated with hydrogens containing all single carbon bonds that are solid at room temperature, such as animal fats (bacon grease, lard).

Unsaturated Fats

Fats containing one or more double bonds that cause kinks preventing close packing, making them liquid at room temperature (plant/fish fats like corn, peanut, and olive oil).

Hydrogenated Oils

Unsaturated fats converted to saturated fats by adding hydrogen, used to make products like margarine solid at room temperature.

Phospholipids

Lipids consisting of glycerol, two fatty acids (hydrophobic tail), and a phosphate group (hydrophilic head) that form cell bilayers.

Steroids

Lipids characterized by four carbon rings, such as cholesterol which is a component of animal cells that forms other steroids including sex hormones.

Amino Acid

The monomer of proteins, containing an amino group, a carboxyl group, and a variable R-group attached to a central carbon.

R-group

The side chain that gives an amino acid its specific chemical properties; hydrophobic R-groups contain $CH$ molecules while hydrophilic R-groups contain $OH$ or $NH$ molecules.

Peptide Bond

The covalent bond used to join amino acids together in a protein chain.

Denaturation

The unravelling of a protein's structure that makes it biological inactive.

Primary Structure

The unique sequence of amino acids linked by covalent bonds that cannot be denatured.

Secondary Structure

Protein structure consisting of alpha helices and beta pleated sheets stabilized by hydrogen bonds between every 4th peptide bond, which can be denatured.

Tertiary Structure

Three-dimensional protein structure determined by R-group interactions, including hydrogen bonds, hydrophobic interactions, and disulfide bridges, which can be denatured.

Quaternary Structure

A complex protein molecule structure composed of multiple aggregated polypeptide chains, which can be denatured.