Chapter 2: Chemical Level of Organization

Vocabulary flashcards covering key terms and concepts from Chapter 2: Chemical Level of Organization, including atomic structure, chemical bonds, reactions, solutions, and biological macromolecules.

Matter

Anything that occupies space and has mass.

Mass

The amount of matter contained in an object, which remains the same on Earth as in the zero-gravity of outer space.

Element

A pure substance that is distinguished from all other matter by the fact that it cannot be created or broken down by ordinary chemical means.

Compound

A substance composed of two or more elements joined by chemical bonds.

Atom

The smallest quantity of an element that retains the unique properties of that element.

Proton

The positively charged particle of an atom that gives mass to the atom and is located within the nucleus.

Neutron

The non-charged particle that gives mass to the atom and is located within the nucleus.

Electron

The negatively charged particle of an atom that exists in a cloud or shell surrounding the nucleus.

Atomic number

The number of protons in the nucleus of an atom, which identifies the element.

Mass number

The sum of the number of protons and neutrons in an element's nucleus.

Isotope

One of the different forms of an element, distinguished from one another by different numbers of neutrons in the nucleus.

Radioisotopes

Heavy and unstable isotopes that exhibit radioactivity.

Electron shell

A layer of electrons that encircle the nucleus at a distinct energy level.

Valence shell

An atom's outermost electron shell, which determines its reactivity with other atoms.

Rule of Eight

A valence shell filling convention which notes that an atom is least reactive when its outer valence shell is full or has at least $8$ electrons.

Molecule

Two or more atoms of different or same element held together by a chemical bond.

Bond

A weak or strong electrical attraction that holds atoms in the same vicinity.

Ion

An atom that has a net positive ($+$) or negative ($-$) charge.

Cation

A positively charged ion.

Anion

A negatively charged ion.

Ionic Bond

An ongoing, close association between ions of opposite charge involving the transfer of electrons from one atom to another.

Covalent Bond

A bond where atoms in a molecule share electrons in a mutually stabilizing relationship rather than donating or accepting them.

Non-polar covalent bond

A covalent bond with an equal sharing of electrons between two different atoms, creating no electrical imbalance.

Polar covalent bond

A covalent bond with an unequal sharing of electrons, where electrons spend more time around one atom than the other to create an imbalance of electrical charge.

Hydrogen Bond

A weak chemical bond formed when a weakly positive hydrogen atom already bonded to an electronegative atom is attracted to another electronegative atom from another molecule.

Metabolism

The sum total of all chemical reactions that go on to maintain an organism's health and life.

Kinetic Energy

The form of energy powering any type of matter in motion.

Potential Energy

The energy matter possesses because of the positioning or structure of its components.

Chemical Energy

The form of potential energy in which energy is stored in chemical bonds.

Reactant

A general term used for the one or more substances that enter into a chemical reaction.

Product

The one or more substances produced by a chemical reaction.

Synthesis Reaction

An anabolic reaction involving the joining of components that were formerly separate, absorbing and storing chemical energy in a bond.

Decomposition Reaction

A catabolic reaction in which something larger breaks down into its component parts, releasing chemical energy by breaking a bond.

Exchange Reaction

A reaction in which both synthesis and decomposition occur, forming and breaking chemical bonds while energy is absorbed, stored, and released.

Inorganic Compound

A substance that does not contain both carbon AND hydrogen, such as $H_2O$, $HCl$, and $CO_2$.

Organic Compound

A substance synthesized via covalent bonds within living organisms that contains BOTH carbon and hydrogen.

Heat Sink

A substance or object that absorbs and dissipates heat but does not experience a corresponding increase in temperature.

Dehydration synthesis

A chemical reaction in which one reactant gives up a hydrogen atom ($H$) and another gives up a hydroxyl group ($OH$) to synthesize a new product.

Hydrolysis

A chemical reaction in which a water molecule disrupts a compound by breaking its bonds, splitting water into hydrogen ($H$) and hydroxyl ($OH$).

Mixture

A combination of two or more substances, each of which maintains its own chemical identity and are not chemically bonded into a new compound.

Solution

A homogeneous liquid mixture in which a solute is evenly distributed and dissolved in a solvent.

Acid

A substance that releases hydrogen ions ($H^+$) in solution.

Base

A substance that releases hydroxyl ions ($OH^-$) in solution.

pH

The measure of relative acidity or alkalinity of a solution, determined by the negative, base-10 logarithm of its hydrogen ion ($H^+$) concentration.

Buffer

A solution of a weak acid and its conjugate base that neutralizes small amounts of acids or bases in body fluids to maintain homeostasis.

Monosaccharide

A monomer and building block of carbohydrates with the base chemical formula $(CH_2O)_n$.

Disaccharide

A pair of monosaccharides formed via dehydration synthesis joined by a glycosidic bond.

Polysaccharide

A carbohydrate structure containing a few to a thousand or more monosaccharides.

Triglycerides

A common dietary lipid formed by dehydration synthesis of glycerol and three fatty acid chains.

Saturated fatty acids

Fatty acid chains with no double carbon bonds and maximum hydrogen atoms, which are solid at room temperature.

Phospholipid

A lipid molecule that composes the bilayer structure of cell membranes.

Prostaglandin

A lipid signaling molecule used in the regulation of blood pressure, inflammation, and pain.

Peptide bond

A covalent bond formed between amino acid subunits via dehydration synthesis reactions.

Essential amino acid

One of $9$ amino acids that cannot be synthesized within the body and must be obtained through the diet.

Fibrous proteins

Elongated, hydrophobic, strong, and durable structural proteins of secondary structure.

Globular proteins

Globe- or sphere-shaped, highly reactive, hydrophilic proteins of tertiary or quaternary structure held together by hydrogen bonds.

Enzyme

A type of globular protein that causes chemical reactions in the body to occur or to occur at a very rapid rate.

Deoxyribonucleic Acid (DNA)

A nucleic acid that stores genetic information, composed of adenine, cytosine, guanine, and thymine bases.

Ribonucleic Acid (RNA)

A nucleic acid used to manifest the genetic code as protein, composed of adenine, cytosine, guanine, and uracil bases.

Adenosine Triphosphate (ATP)

The primary energy molecule of the body containing two high-energy covalent bonds linking its three phosphates.