Chapter 2: Chemistry Comes Alive Flashcards

Vocabulary practice flashcards generated from Chapter 2: Chemistry Comes Alive lecture notes.

Matter

Anything that occupies space and has mass, existing in solid, liquid, or gaseous states.

Kinetic energy

Energy in motion.

Potential energy

Stored energy.

Second Law of Thermodynamics

A general principle stating that all processes in Nature tend to increase the disorder of matter.

Elements

Unique substances that cannot be broken down into simpler substances by ordinary chemical methods.

Atom

The basic building block of an element, composed of a central positively charged nucleus surrounded by orbiting negatively charged electrons.

Atomic symbol

A one- or two-letter chemical shorthand designating an element, derived from its English or Latin name.

Protons

Subatomic particles located in the atomic nucleus that bear a positive electrical charge.

Neutrons

Subatomic neutral particles located in the atomic nucleus.

Electrons

Subatomic particles bearing a negative electrical charge that orbit the atomic nucleus.

Planetary model

A simplified representation of atomic structure depicting electrons moving around the nucleus in fixed, circular orbits.

Molecules

Combinations of two or more atoms held together by chemical bonds.

Compounds

Substances formed when two or more different kinds of atoms bind together chemically.

Mixtures

Substances composed of two or more components physically intermixed without chemical bonding.

Solutions

Homogeneous mixtures of compounds where the solvent is the substance present in the greatest amount and solutes are present in smaller amounts.

Colloids

Heterogeneous mixtures containing solute particles that scatter light, do not settle out, and can undergo sol-gel transformations.

Suspensions

Heterogeneous mixtures containing large solutes and particles that tend to settle out over time.

Chemical bond

An energy relationship between the electrons of reacting atoms, rather than a physical structure.

Ionic bonds

Chemical bonds formed between atoms by the complete transfer of one or more electrons from one atom to another.

Cation

A positively charged ion formed when an atom loses one or more electrons.

Anion

A negatively charged ion formed when an atom gains one or more electrons.

Covalent bonds

Chemical bonds produced when reacting atoms share electrons that occupy a single orbital common to both atoms.

Hydrogen bonds

Weak attractions formed when a hydrogen atom covalently linked to an electronegative atom is attracted by another electron-hungry atom.

Carbohydrates

A group of organic molecules including sugars and starches composed of carbon, hydrogen, and oxygen that represent 1–2% of cell mass.

Monosaccharides

Simple sugars containing from 3 to 7 carbon atoms that serve as the building blocks of carbohydrates.

Disaccharides

Double sugars formed when two monosaccharides are joined together by dehydration synthesis.

Polysaccharides

Long branching chains or polymers of linked monosaccharides, such as plant starch and animal glycogen.

Triglycerides

Neutral fats composed of three fatty acid chains bound to a single glycerol backbone.

Phospholipids

Amphipathic lipid molecules containing a glycerol backbone, two nonpolar fatty acid tails, and a polar phosphorus-containing head.

Steroids

Molecules constructed from four interlocking hydrocarbon rings, with cholesterol serving as the structural basis for all body steroids.

Amino acids

Amphipathic building blocks of proteins containing an acidic group, an amine group, and a variable R group.

Peptide bonds

Covalent bonds that link amino acids together via dehydration synthesis between an amine group and an acid group.

Primary structure

The linear sequence of amino acids composing a polypeptide chain.

Secondary structure

The structural level where a primary amino acid chain twists into spiral $\alpha$-helices or bends into pleated $\beta$-sheets.

Tertiary structure

The compact ball-like globular molecule formed when secondary structures fold upon one another.

Quaternary structure

The structural level achieved when two or more polypeptide chains with tertiary structure aggregate to form a complex protein.

Enzymes

Globular proteins that function as biological catalysts to increase the rates of chemical reactions.

Activation energy

The amount of energy required to break the bonds of reactants so a chemical reaction can proceed.

Nucleotides

Structural units of nucleic acids consisting of a nitrogen-containing base, a pentose sugar, and a phosphate group.

Deoxyribonucleic acid (DNA)

A double-stranded helical polymer located in the cell nucleus that stores genetic instructions for protein synthesis.

Ribonucleic acid (RNA)

A single-stranded nucleic acid located primarily in the cytoplasm that carries out genetic instructions for protein synthesis.

Adenosine triphosphate (ATP)

An adenine-containing RNA nucleotide with three phosphate groups that provides directly usable energy for cellular work.