Chapter 2 Vocabulary

Flashcards covering the key vocabulary and definitions from Chapter 2: Basic Chemistry.

Matter

Anything that occupies space and has mass.

Mass

The amount of matter in an object.

Energy

The capacity to do work.

Kinetic Energy

Energy of movement.

Potential Energy

Inactive or stored energy.

Chemical Energy

Stored in chemical bonds.

Electrical Energy

Results from the movement of charged particles.

Mechanical Energy

Energy directly involved with moving matter.

Radiant Energy

Energy that travels in waves.

Elements

Unique substances that cannot be broken down into simpler substances.

Atoms

Mostly identical building blocks of an element.

Atomic symbol

One- or two-letter abbreviation for an element.

Protons

Particles in the nucleus with a positive charge.

Neutrons

Particles in the nucleus with no charge.

Electrons

Occupy random positions within orbitals surrounding the nucleus, have a negative charge.

Atomic Number

Equal to the number of protons of an element in an atom.

Mass Number

Equal to the number of protons plus the number of neutrons in an atom.

Isotopes

Structural variations of an atom that have the same number of protons, but different numbers of neutrons..

Atomic Weight

A weighted average of the mass numbers of all known isotopes of an element, based on their relative abundance in nature.

Radioisotopes

Heavier, unstable isotopes of an element that spontaneously decompose into more stable forms, producing radioactivity.

Half-life

The time for a radioisotope to lose one-half of its radioactivity.

Molecule

A combination of two or more atoms.

Molecule of an element

A combination of two or more of the same atoms.

Molecule of a compound

A combination of two or more different atoms.

Mixtures

Consist of two or more substances that are physically mixed.

Solutions

Homogeneous mixtures of compounds that may be gases, liquids, or solids.

Solvent

The substance present in the greatest amount in a solution.

Solutes

Substances dissolved in the solvent in a solution.

Colloids

Heterogeneous mixtures that often appear milky and have larger solute particles that do not settle out of solution.

Suspensions

Heterogeneous mixtures with large, often visible solutes that will settle out of solution.

Chemical Bond

An energy relationship between the electrons of the reacting atoms.

Ionic bonds

Chemical bonds that form between two atoms when one or more electrons are transferred from one atom to the other.

Anion

An atom that gains an electron, taking on a negative charge.

Cation

An atom that loses an electron acquires a positive charge.

Covalent Bonds

Occur when pairs of atoms share electrons, and atoms may share one, two, or three pairs of electrons, forming single, double, or triple bonds.

Nonpolar covalent bonds

Have an equal distribution of the shared electrons’ charge across the bond.

Polar covalent bonds

Electrons are more attracted to one atom (an electronegative atom) than the other (an electropositive atom).

Hydrogen bonds

Formed when a hydrogen that is covalently bonded to one atom (often oxygen or nitrogen) is attracted to another electronegative atom, forming a sort of “bridge.”

Chemical equation

Describes what happens in a reaction by indicating number and type of reactants, chemical composition of the products, and the relative proportion of each reactant and product (if balanced).

Synthesis (combination) reactions

Involve formation of chemical bonds and are the basis of anabolic, or constructive, processes in cells.

Decomposition reaction

A molecule is broken down into smaller molecules by breaking chemical bonds, and is a degradative, or catabolic, process.

Exchange (displacement) reactions

Involve both synthesis and decomposition reactions, and involve parts of reactants “trading places,” forming new products.

Oxidation-reduction reactions

Special exchange reactions in which electrons are exchanged between reactants.

Exergonic reactions

Energy is released, producing products that have lower potential energy than the reactants.

Endergonic reactions

Result in products that contain more potential energy than the reactants.

Chemical equilibrium

Occurs when the rate of the forward reaction equals the rate of the reverse reaction, resulting in no net change in the amount of reactants or products.

Catalysts

Increase the rate of a chemical reaction without taking part in the reaction.

Water

Most important inorganic molecule, makes up 60–80% of the volume of most living cells.

High heat capacity

Absorbs and releases a great deal of heat before it changes temperature.

High heat of vaporization

Takes a great deal of energy (heat) to break the bonds between water molecules.

Solvent

Polar molecule that plays a role in dissociation of ionic molecules.

Salts

Ionic compounds containing cations other than H+ and anions other than the hydroxyl (OH–) ion that dissociate in water into their component ions when dissolved.

Electrolytes

Conduct electrical currents in solution.

Acids

Proton donors, have a sour taste & dissociate in water to yield hydrogen ions & anions.

Bases

Proton acceptors, taste bitter, feel slippery, and absorb hydrogen ions.

pH

The relative concentration of hydrogen ions is measured in concentration units.

Neutralization

An acid & a base are mixed, creating displacement reactions that form a salt & water.

Buffers

A combination of a weak acid and weak base that resists large fluctuations in pH that would be damaging to living tissues.

Dehydration synthesis

A hydrogen atom is removed from one monomer, and a hydroxyl group is removed from the atom to be paired with.

Hydrolysis

A water molecule is used to split the covalent bond between two atoms, in reverse of dehydration synthesis.

Organic compounds

Molecules unique to living systems, & all contain carbon.

Biomolecules

Large complex molecules made of thousands of atoms.

Macromolecules

Chainlike molecules made of many smaller subunits.

Polymers

Chainlike molecules made of many smaller subunits, called monomers, joined by dehydration synthesis.

Carbohydrates

A group of molecules, classified as either monosaccharides, disaccharides, or polysaccharides, that contain carbon hydrogen and oxygen, and include sugars and starches.

Monosaccharides

Simple sugars, named for the number of carbons they contain, that are single- chain or single-ring structures.

Disaccharides

Formed when two monosaccharides are joined by dehydration synthesis.

Polysaccharides

Long chains of monosaccharides linked together by dehydration synthesis.

Energy Source

In the body, carbohydrates are primarily used as an enegy source.

Lipids

Insoluble in water, but dissolve readily in nonpolar solvents, and include triglycerides, phospholipids, steroids, and other lipoid molecules.

Triglycerides

Consist of glycerol (a sugar alcohol), and fatty acids (linear hydrocarbon chains).

Insulation and mechanical protection

Found mainly beneath the skin and serve as insulation and mechanical protection.

Saturated fatty acids

Having only single bonds between adjacent carbons.

Unsaturated fatty acids

Bearing at least one double bond between a pair of carbons in the chain.

Phospholipids

Diglycerides with a phosphorus-containing group and two fatty acid chains that are primarily used to construct cell membranes.

Steroids

Flat molecules made up of four interlocking hydrocarbon rings and are used in the body in cell membranes and hormones.

Eicosanoids

Derived from arachidonic acid, and function in blood clotting, and regulation of blood pressure, inflammation, and labor contractions.

Proteins

The basic structural material of the body and play vital roles in cell function.

Amino Acids

Long chains of amino acids connected by peptide bonds, which join the amine of one amino acid to the acid of the next.

Primary structure (of a protein)

The linear sequence of amino acids.

Secondary structure(of a protein)

Proteins twist and turn on themselves to form a more complex structure.

Tertiary structure (of a protein)

Results from protein folding upon itself to form a ball -like structure.

Quaternary structure (of a protein)

Two or more polypeptide chains grouped together to form a complex protein.

Fibrous proteins

Extended, strand-like, insoluble molecules that provide mechanical support and tensile strength to tissues.

Globular proteins

Compact, spherical, water-soluble, and chemically active molecules that oversee most cellular functions.

Enzymes

Globular proteins that act as biological catalysts, enabling biological processes to happen quickly enough to support life.

Active site

The location on the protein that catalyzes the reaction.

Activation energy

The energy required by a reaction.

Nucleic Acids

Primary classes are deoxyribonucleic acid (DNA) & ribonucleic acid (RNA).

DNA

The genetic material of the cell and is found within the nucleus.

RNA

Located outside the nucleus and is used to make proteins using the instructions provided by the DNA.

Nucleotides

The structural units of nucleic acids and consist of three components: a nitrogen- containing base, a pentose sugar, and a phosphate group.

Nitrogenous bases

Five nitrogenous bases are used in nucleic acids: two large, double-ringed purines: adenine (A) and guanine (G), and three smaller, single-ring pyrimidines: cytosine (C), uracil (U), and thymine (T).

DNA Structure

A double - stranded polymer containing the nitrogenous bases adenine, thymine, guanine, and cytosine, and the sugar deoxyribose that spiral into a double helix.

RNA Structure

A single -stranded polymer containing the nitrogenous bases A, G, C, and U, and the sugar ribose.

ATP (adenosine triphosphate)

The primary energy transfer molecule used in the cell.

ATP is composed of:

An adenine-containing RNA nucleotide that has two additional phosphate groups attached, connected by high-energy bonds.

Phosphorylation

Energy is transferred from ATP to other systems in cells by removing the terminal phosphate from ATP and binding it to other compounds.