Chapter 2: Chemical Level of Organization

Comprehensive vocabulary flashcards covering subatomic structure, chemical bonds, reactions, enzymes, water properties, pH, organic macromolecules, and high-energy compounds.

Chemistry

The science that deals with the structure of matter.

Matter

Anything that takes up space and has mass.

Atom

The smallest possible unit of matter, composed of subatomic particles including protons, neutrons, and electrons.

Proton

A positively charged subatomic particle found in the nucleus with a mass similar to a neutron.

Neutron

An electrically neutral subatomic particle found in the nucleus with a mass similar to a proton.

Electron

A negatively charged, lighter subatomic particle that orbits the nucleus.

Atomic Number

The unique number of protons in an atom that defines each element.

Element

A pure substance composed of atoms of one kind that cannot be broken down into simpler substances by ordinary physical means.

Isotopes

Versions of an element that have different numbers of neutrons.

Mass Number

The number of protons plus the number of neutrons in an atom, unique for each isotope.

Radioisotopes

Isotopes with unstable nuclei that undergo radioactive decay.

Half-life

The time required for half of a given amount of a radioisotope to decay.

Atomic Weight

An average of the different atomic masses and proportions of different isotopes of an element.

Mole (mol)

A specific quantity in grams equal to the atomic weight of an element, containing Avogadro's number ($6.023 \times 10^{23}$) of atoms.

Valence Shell

The outermost electron shell of an atom whose number of electrons determines the chemical properties of an element.

Molecule

Two or more atoms joined together by shared electrons.

Compound

A substance composed of two or more atoms of different elements.

Ionic Bond

A chemical bond created by the attraction between oppositely charged positive and negative ions.

Cation

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

Anion

A negatively charged ion formed when an electron acceptor gains donated electrons.

Covalent Bond

A strong chemical bond created when atoms share electrons.

Nonpolar Covalent Bond

A covalent bond with equal sharing of electrons between two atoms that have an equal pull on the electrons.

Polar Covalent Bond

A covalent bond featuring unequal sharing of electrons between two atoms, creating partial positive and partial negative charges.

Hydrogen Bond

A weak electrical attraction between the partial positive charge of a hydrogen atom in a polar covalent bond and the partial negative charge of an oxygen, nitrogen, or fluorine atom in another polar covalent bond.

Metabolism

All chemical reactions occurring in the cells and tissues of the body at any given time.

Kinetic Energy

The energy of motion.

Potential Energy

Stored energy an object possesses because of its position or its physical or chemical structure.

Catabolism

Decomposition reactions that break molecules into smaller fragments and release energy to power cellular processes.

Anabolism

Synthesis reactions that assemble larger molecules from smaller molecules, using energy to form chemical bonds.

Hydrolysis Reaction

A decomposition reaction involving water that breaks chemical bonds, represented as $\text{AB} + \text{H}_2\text{O} \rightarrow \text{AH} + \text{BOH}$.

Dehydration Synthesis

A synthesis reaction that joins molecules together and produces a water molecule, represented as $\text{AH} + \text{BOH} \rightarrow \text{AB} + \text{H}_2\text{O}$.

Activation Energy

The amount of energy needed to start a chemical reaction.

Enzyme

A biological catalyst that lowers the activation energy of reactions and speeds them up without being changed or consumed.

Exergonic Reaction

A chemical reaction in which the amount of energy released is greater than the activation energy, producing a net release of energy.

Endergonic Reaction

A chemical reaction in which the activation energy required is more than the energy produced, causing the reaction to absorb energy.

Inorganic Compounds

Compounds that do not contain carbon bonded to hydrogen as their primary structural component.

Organic Compounds

Compounds that contain carbon in bonds to hydrogen as a primary component.

High Heat Capacity

The property of water requiring a large quantity of heat to raise the temperature of a unit mass by $1\,^{\circ}\text{C}$, allowing it to resist temperature changes.

Hydration Sphere

A sheath of oriented water molecules that surrounds ions and small polar molecules to keep them in solution.

Electrolytes

Soluble inorganic substances whose ions conduct electrical current in solution.

Hydrophilic

Molecules or ions that readily interact with water.

Hydrophobic

Nonpolar molecules, fats, or oils that do not interact readily with water.

Colloid

A solution containing dispersed proteins or other large molecules that do not settle out, such as blood plasma.

Suspension

A mixture containing large particles in solution that will settle out if left undisturbed, such as whole blood.

pH

The negative logarithm of the hydrogen ion concentration ($-\log_{10}[\text{H}^+]$) of a solution in moles per liter.

Acid

Any solute that acts as a proton donor by adding hydrogen ions ($\text{H}^+$) to a solution.

Base

Any solute that acts as a proton acceptor by removing hydrogen ions ($\text{H}^+$) from a solution.

Buffer

A compound that stabilizes the pH of a solution by neutralizing added acids or bases.

Functional Groups

Specific groupings of atoms in organic compounds that influence their chemical properties.

Isomers

Molecules that share the same molecular formula but have different structural arrangements.

Carbohydrates

Organic macromolecules containing carbon, hydrogen, and oxygen in a $1:2:1$ ratio that serve as a primary energy source.

Monosaccharides

Simple sugars containing three to seven carbon atoms, such as glucose and fructose.

Disaccharides

Carbohydrates composed of two monosaccharides joined by dehydration synthesis, such as sucrose.

Polysaccharides

Complex carbohydrates formed from polymers of many monosaccharides joined together by dehydration synthesis.

Lipids

Organic macromolecules containing carbon and hydrogen in a $1:2$ ratio with relatively little oxygen.

Saturated Fatty Acid

A fatty acid chain with no double bonds in its hydrocarbon tail, saturated with hydrogen.

Unsaturated Fatty Acid

A fatty acid chain containing one or more double bonds in its hydrocarbon tail.

Eicosanoids

Lipids derived from arachidonic acid, including leukotrienes and prostaglandins.

Triglycerides

Neutral fats consisting of a glycerol molecule attached to three fatty acid chains.

Steroids

Large lipid molecules that feature a distinct four-ringed carbon structure, such as cholesterol and sex hormones.

Phospholipids

Structural lipids consisting of a diglyceride attached to a phosphate group and nonlipid group, featuring hydrophilic heads and hydrophobic tails.

Micelles

Droplet spheres formed when phospholipids or glycolipids aggregate in water with hydrophobic tails facing inward and hydrophilic heads outward.

Amino Acids

The monomer building blocks of proteins, consisting of a central carbon, hydrogen atom, amino group ($-\text{NH}_2$), carboxyl group ($-\text{COOH}$), and variable R group.

Peptide Bond

A covalent bond linking two amino acids together formed via dehydration synthesis between the amino group of one and carboxyl group of another.

Primary Structure

The specific linear sequence of amino acids along a polypeptide chain.

Secondary Structure

Protein structure resulting from hydrogen bonding along the polypeptide chain, producing alpha helices or beta sheets.

Tertiary Structure

The complex three-dimensional coiling and folding of a protein resulting from interactions between R groups.

Quaternary Structure

Protein structure resulting from the interaction between two or more polypeptide chains.

Denaturation

The loss of a protein or enzyme's three-dimensional structure resulting in a loss of function.

Active Site

A specific region on an enzyme where substrate molecules bind to undergo a chemical reaction.

Cofactor

An ion or molecule that must bind to an enzyme before substrates can bind.

Coenzyme

Nonprotein organic cofactors, such as vitamins, that assist enzyme function.

Nucleic Acids

Large organic macromolecules composed of carbon, hydrogen, oxygen, nitrogen, and phosphorus that store and process genetic information.

Nucleotide

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

DNA (Deoxyribonucleic Acid)

A double-stranded nucleic acid containing deoxyribose sugar and bases Adenine, Thymine, Cytosine, and Guanine, coiled in a double helix.

RNA (Ribonucleic Acid)

A single-stranded nucleic acid containing ribose sugar and bases Adenine, Uracil, Cytosine, and Guanine, involved in protein synthesis.

Purines

Two-ringed nitrogenous bases found in nucleic acids, which include Adenine ($\text{A}$) and Guanine ($\text{G}$).

Pyrimidines

Single-ringed nitrogenous bases found in nucleic acids, which include Cytosine ($\text{C}$), Thymine ($\text{T}$), and Uracil ($\text{U}$).

Phosphorylation

The chemical process of attaching a phosphate group to another molecule.

Adenosine Triphosphate (ATP)

The principal high-energy compound in cells, formed by attaching three phosphate groups to adenosine monophosphate via high-energy bonds.