Vocab

Isotope

Atoms of the same element that have different numbers of neutrons.

Valence electrons

Electrons in the outer shell of an atom that are involved in chemical bonding.

Covalent bond

A chemical bond formed by the sharing of electron pairs between atoms.

Ionic bond

A chemical bond formed through the transfer of electrons from one atom to another, resulting in attraction between oppositely charged ions.

Hydrogen bond

A weak bond formed between a hydrogen atom covalently bonded to an electronegative atom and another electronegative atom.

Polar Molecule

A molecule that has a partial positive charge on one end and a partial negative charge on the other.

Nonpolar Molecule

A molecule that has no separation of charge, resulting in no positive or negative ends.

Electronegativity

The tendency of an atom to attract electrons in a chemical bond.

Cohesion

The attraction between molecules of the same substance.

Adhesion

The attraction between molecules of different substances.

Surface Tension

The cohesive force that causes the molecules at the surface of a liquid to be pushed together.

Specific Heat

The amount of heat required to raise the temperature of a substance by one degree Celsius.

Heat of Vaporization

The amount of energy required to convert a unit mass of a liquid into vapor.

Evaporative Cooling

A process in which the surface of an object becomes cooler during evaporation.

Aqueous solution

A solution in which water is the solvent.

Hydrophilic

Substances that have an affinity for water.

Hydrophobic

Substances that do not have an affinity for water.

pH

A measure of the acidity or basicity of a solution.

Buffer

A substance that minimizes changes in pH when acids or bases are added.

Isomer

Compounds that have the same chemical formula but different structural arrangements.

Structural isomer

Isomers that differ in the covalent arrangements of their atoms.

Cis-trans isomer

Isomers that differ in the arrangement of groups around a double bond.

Enantiomer isomer

Isomers that are mirror images of each other.

Functional Group

A specific group of atoms that are responsible for the characteristic reactions of a compound.

Hydroxyl

A functional group consisting of an oxygen atom bonded to a hydrogen atom (-OH).

Carbonyl

A functional group characterized by a carbon atom double-bonded to an oxygen atom (C=O).

Carboxyl

A functional group containing both a carbonyl and a hydroxyl group (-COOH).

Amino

A functional group consisting of a nitrogen atom bonded to two hydrogen atoms (-NH2).

Phosphate

A functional group consisting of a phosphorus atom bonded to four oxygen atoms (-PO4).

Methyl

A functional group consisting of a carbon atom bonded to three hydrogen atoms (-CH3).

Macromolecule

A large molecule composed of smaller structural units (monomers) bonded together.

Monomer

A small molecule that can join together with other small molecules to form larger molecules.

Polymer

A large molecule made up of repeating structural units (monomers).

Dehydration Synthesis

A reaction that joins two molecules, resulting in the loss of water.

Hydrolysis

A reaction that breaks down a compound by adding water.

Carbohydrates

Organic compounds made up of carbon, hydrogen, and oxygen, typically in a 1:2:1 ratio.

Monosaccharide

The simplest form of carbohydrates, consisting of single sugar units.

Polysaccharide

Carbohydrates that are made up of more than two monosaccharides.

Glycosidic Linkage

The bond formed between two monosaccharides through dehydration synthesis.

Cellulose

A structural polysaccharide found in plant cell walls.

Lipid

A diverse group of hydrophobic organic molecules, including fats and oils.

Fatty acid

A carboxylic acid with a long aliphatic chain.

Saturated fatty acid

Fatty acids that contain no double bonds between carbon atoms.

Unsaturated fatty acid

Fatty acids that contain one or more double bonds between carbon atoms.

Phospholipid

A lipid containing a phosphate group; forms the bilayer of cell membranes.

Steroids

Lipids characterized by a carbon skeleton consisting of four fused rings.

Protein

A macromolecule made up of amino acids and plays critical roles in biological processes.

Polypeptide

A chain of amino acids linked by peptide bonds.

Amino Acid

The building blocks of proteins, consisting of an amino group, carboxyl group, and variable side chain.

Peptide Bond

The bond formed between two amino acids during protein synthesis.

Primary Structure

The unique sequence of amino acids in a polypeptide chain.

Secondary Structure

The localized folding of polypeptides into structures like alpha-helices and beta-sheets.

Tertiary Structure

The overall three-dimensional shape of a polypeptide.

Quaternary Structure

The structure formed when two or more polypeptide chains associate to form a functional protein.

Denature

The process by which proteins lose their structure due to environmental conditions.

Nucleic Acid

Biological molecules essential for life, including DNA and RNA.

Nucleotide

The basic building block of nucleic acids, consisting of a sugar, phosphate group, and nitrogenous base.

Enzyme

A protein that acts as a catalyst to accelerate a chemical reaction.

Catalyst

A substance that increases the rate of a chemical reaction without being consumed.

Activation Energy

The minimum energy required to start a chemical reaction.

Substrate

The reactant or substance upon which an enzyme acts.

Active Site

The specific region of an enzyme where the substrate binds.

Cofactors

Non-protein molecules that assist enzymes in catalyzing reactions.

Coenzymes

Organic cofactors, often derived from vitamins, that assist enzymes.

Competitive Inhibition

A process in which a substance competes with the substrate for binding to the active site of an enzyme.

Noncompetitive Inhibition

An inhibitor binds to an enzyme at a site other than the active site, altering the enzyme's activity.

Allosteric Enzymes

Enzymes that are regulated by the binding of molecules at sites other than the active site.

Cooperativity

A form of allosteric regulation that can amplify enzyme activity.

Feedback Inhibition

A regulatory mechanism in which the end product of a reaction inhibits an enzyme involved in its production.

Prokaryote

Single-celled organisms that lack a nucleus and membrane-bound organelles.

Eukaryote

Organisms made up of cells that contain a nucleus and membrane-bound organelles.

Diffusion

The passive movement of molecules from an area of higher concentration to an area of lower concentration.

Osmosis

The diffusion of water through a selectively permeable membrane.

Hypotonic Solution

A solution with a lower concentration of solutes compared to the inside of the cell.

Hypertonic Solution

A solution with a higher concentration of solutes compared to the inside of the cell.

Isotonic Solution

A solution with the same concentration of solutes as the inside of the cell.

Facilitated Diffusion

The process by which molecules pass across a membrane through protein channels.

Surface Area: Volume

A ratio that describes the relationship between an object's surface area and its volume, impacting cell function and efficiency.

Endocytosis

The process by which a cell takes in material by engulfing it in an energy-using process.

Exocytosis

The process by which a cell expels materials in vesicles.

Active Transport

The energy-requiring process of moving substances across a membrane against their concentration gradient.

Water Potential

A measure of the potential energy in water, influencing the movement of water in and out of cells.

Phospholipids

Lipid molecules that are a fundamental component of cellular membranes.

Glycoproteins

Proteins that have carbohydrates covalently bonded to them, often playing a role in cell recognition.

Glycolipids

Lipids with a carbohydrate attached, playing a role in cell membrane structure.

Proteins (Integral & Peripheral)

Integral proteins span the membrane, while peripheral proteins are loosely attached to the membrane surface.

Aquaporins

Channel proteins that facilitate the transport of water across cell membranes.

Endergonic

Reactions that absorb free energy from their surroundings, non-spontaneous.

Exergonic

Reactions that release energy, spontaneous.

Gibbs Free Energy

The energy associated with a chemical reaction that can be used to do work.

Enthalpy

The total heat content of a system and the measure of energy flow in a system.

Entropy

A measure of disorder or randomness in a system.

Photosynthesis

The process by which green plants use sunlight to synthesize foods from carbon dioxide and water.

Chemiosmosis

The movement of ions across a selectively permeable membrane, down their electrochemical gradient.

ATP Synthase

An enzyme that creates ATP from ADP and inorganic phosphate during cellular respiration.

ATP

A high-energy molecule that stores and provides energy for cellular processes.

Cellular Respiration

The process through which cells convert glucose and oxygen into energy.

Glycolysis

The process of breaking down glucose to form pyruvate, producing a small amount of ATP.

Krebs Cycle

A series of chemical reactions used by all aerobic organisms to release stored energy.

Electron Transport Chain

A series of protein complexes in the inner mitochondrial membrane that transfer electrons and pump protons to create ATP.