Chemical Basis of Life

Vocabulary flashcards covering the fundamental concepts of the chemical basis of life, including atomic structure, chemical bonding, reactions, and the major classes of organic and inorganic molecules.

Chemistry

The study of matter.

Biochemistry

The chemistry of living organisms.

Matter

Anything that occupies space and has mass, including solids, liquids, and gases.

Atom

The smallest particle of an element.

Element

A basic chemical substance composed of atoms, represented by a 1 or 2 letter symbol.

Proton

A positively charged particle found in the nucleus of an atom with a mass of $1\,amu$.

Neutron

An electrically neutral particle found in the nucleus of an atom with a mass of $1\,amu$.

Electron

An electrically negative particle that revolves around the nucleus with a mass of $0$.

Atomic Number (A#)

The number of protons in the nucleus of an atom.

Atomic Weight (AW)

Nearly equal to the number of protons plus the number of neutrons in an atom's nucleus.

Isotopes

Atoms of an element that have the same A#'s but different AW's due to a different number of neutrons.

Molecule

Formed when two or more atoms combine chemically.

Compound

Formed when atoms of different elements combine, such as water ($H_2O$) or glucose ($C_6H_{12}O_6$).

Valence Electrons

The electrons in the outermost shell of an atom that determine its chemical properties.

Octet Rule

The principle that atoms react with other atoms to achieve 8 electrons in their valence shell, except for the first energy level.

Ionic Bonds

Bonds formed when atoms exchange electrons to fill their valence shells, resulting in an attraction between oppositely charged ions.

Ions

Atoms that have lost or gained electrons to fill their valence shell.

Cation

A positively charged ion, such as $Na^+$, formed by losing an electron.

Anion

A negatively charged ion, such as $Cl^-$, formed by gaining an electron.

Covalent Bonds

Bonds formed by the sharing of electrons between atoms to fill their valence shells.

Non-polar covalent bonds

Covalent bonds where electrons are shared equally between the atoms.

Polar covalent bonds

Covalent bonds where electrons are shared unequally, resulting in a molecule with slightly positive and negative ends.

Hydrogen Bonds

Weak, easily broken bonds formed between a slightly positive hydrogen atom and another slightly negative atom.

Chemical Reaction

The process that occurs whenever chemical bonds are formed, rearranged, or broken.

Reactants

The initial chemicals involved in a chemical reaction.

Products

The substances formed at the end of a chemical reaction.

Synthesis

Constructive, anabolic reactions that build large polymers from smaller monomers, usually requiring energy (endergonic).

Decomposition

Destructive, catabolic reactions that break large molecules into monomers, usually releasing energy (exergonic).

Dehydration

A process where water is removed from building blocks to form a chemical bond.

Hydrolysis

A process where water is used to break chemical bonds between molecules.

Electrolytes

Substances that dissociate in water to form ions and are needed for muscle contraction and nerve impulses.

Acids

Substances that dissociate in water to form hydrogen cations ($H^+$) and an anion.

Bases

Substances that dissociate in water to form hydroxide anions ($OH^-$) and a cation.

Salts

Substances that dissociate in water and form an anion and a cation, neither of which is $H^+$ or $OH^-$.

pH Scale

A scale ranging from 0 to 14 used to measure the relative concentrations of hydrogen and hydroxyl ions.

Buffers

Compounds added to solutions to prevent abrupt changes in pH.

Acidosis

A condition where the body's pH is below 7.4.

Alkalosis

A condition where the body's pH is above 7.4.

Inorganic Substances

Small compounds such as water, oxygen, and carbon dioxide that do not contain both carbon and hydrogen atoms.

Organic Substances

Molecules that contain both carbon and hydrogen, including carbohydrates, lipids, proteins, and nucleic acids.

Carbohydrates

Sugars containing C, H, and O in a 1:2:1 ratio, functioning as an energy source or for energy storage.

Monosaccharides

The simple 6-carbon sugar building blocks of carbohydrates, including glucose, fructose, and galactose.

Glycogen

Animal storage carbohydrate stored in the liver and skeletal muscle.

Starch

Plant storage carbohydrate.

Lipids

Organic molecules containing C, H, and O (with less O than carbohydrates), including fats, phospholipids, and steroids.

Triglycerides

The monomers of fats, composed of one glycerol and three fatty acids.

Saturated fats

Animal fats that have only single bonds between carbons and are solid at room temperature.

Unsaturated fats

Plant fats that have one or more double bonds between carbons and are liquid at room temperature.

Phospholipids

Lipids containing a polar phosphate group ($PO_4^-$) instead of one fatty acid chain; a major cell membrane component.

Steroids

Lipids composed of four interconnected carbon rings, such as cholesterol and certain hormones.

Amino acids

The monomers or building blocks of proteins, consisting of an amino group, a carboxyl group, and an R-group.

Peptide bond

The covalent bond formed between the amino group of one amino acid and the carboxyl group of a second amino acid.

Enzymes

Biological catalysts that increase the rate of chemical reactions without being consumed.

Denaturation

The loss of a protein's 3-dimensional conformation, resulting in a loss of function.

Nucleotides

The building blocks of nucleic acids, consisting of a pentose sugar, a nitrogenous base, and a phosphate group.

DNA (Deoxyribonucleic Acid)

Double-stranded genetic material that directs protein synthesis using the sugar deoxyribose and bases A, T, C, and G.

RNA (Ribonucleic Acid)

Single-stranded nucleic acid that transports DNA code during protein synthesis, using the sugar ribose and bases A, G, C, and uracil.