Anatomy and Physiology - The Chemical Level of Organization

A collection of vocabulary-style flashcards covering the chemical organization of the human body, including atomic structure, chemical bonds, energy, reactions, and organic macromolecules, based on Elizabeth Co's Anatomy and Physiology, 1st Edition.

Matter

Anything that occupies space and has mass.

Mass

The amount of matter contained in an object, which remains the same regardless of an object's location.

Weight

A measurement that can vary because it depends on the force of gravity.

Elements

Pure substances that are made of a single type of atom.

Atom

The smallest unit of an element that retains properties of that element.

Molecule

Two or more atoms chemically bound together.

Compound

Two or more elements joined by chemical bonds.

Proton

A positively charged subatomic particle.

Neutron

A subatomic particle with no charge ($\text{neutral}$).

Electron

A negatively charged subatomic particle.

Atomic number

Represented by the number of protons within an atom.

Atomic weight

The value that equals the number of protons, neutrons, and a small amount of weight from electrons.

Mass number

A value roughly equal to the number of protons and neutrons in the atom.

Isotopes

The different forms of an element that differ in the number of neutrons and atomic weight.

Protium

An isotope of hydrogen consisting of $1$ proton, $1$ electron, and $0$ neutrons.

Deuterium

An isotope of hydrogen consisting of $1$ proton, $1$ electron, and $1$ neutron.

Tritium

An isotope of hydrogen consisting of $1$ proton, $1$ electron, and $2$ neutrons.

Radioactive isotopes

Unstable forms of an element that shed subatomic particles.

Ion

An atom with an electrical charge formed when atoms donate or accept electrons.

Cation

A positively charged ion.

Anion

A negatively charged ion.

Electron shells

Regions around an atom's nucleus that contain electrons, holding from two to eight electrons.

Valence shell

The outermost electron shell of an atom.

Bond

An electrical attraction that holds atoms together.

Ionic Bonds

Bonds formed between ions with opposite charges.

Covalent Bonds

Bonds formed when electrons are shared by atoms to stabilize the valence shell.

Polar covalent bonds

Bonds where electrons are more attracted to certain atoms, leading to unequal sharing and creating partial charges.

Nonpolar covalent bonds

Bonds that occur when electrons are shared equally between atoms.

Hydrogen Bonds

Attractions that occur when molecules are attracted to one another, such as when the negatively charged region of a water molecule is attracted to the positively charged region of another.

Surface tension

A property created between water molecules due to hydrogen bonding.

Potential energy

Stored energy that can be released.

Kinetic energy

The energy of motion.

Chemical energy

A type of potential energy that is stored in chemical bonds.

Exergonic reactions

Chemical reactions that release energy.

Endergonic reactions

Chemical reactions that absorb or require energy.

Adenosine Triphosphate ($ATP$)

A modified nucleotide that serves as the energy currency of the cell, storing energy in covalent bonds between phosphate groups.

Reactants (Substrates)

The substances that enter into a chemical reaction.

Products

The substances produced by a chemical reaction.

Synthesis reaction

A reaction where atoms, molecules, or ions combine to form new molecules, typically joining monomers.

Decomposition reaction

A reaction where larger molecules are broken down into smaller atoms, ions, or molecules.

Exchange reaction

A reaction involving a combination of both synthesis and decomposition reactions.

Activation energy

The minimal energy required for a chemical reaction to occur.

Enzymes

Biological catalysts, mostly proteins, that increase the rate of reactions by lowering activation energy and are unchanged by the reaction.

Active site

The specific location on an enzyme where the substrate binds.

Inorganic compounds

Substances that do not contain both carbon and hydrogen, such as water, salts, acids, bases, and carbon dioxide.

Organic compounds

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

Water

A substance making up $50\text{--}70\%$ of an adult body, providing lubrication, cushioning, temperature regulation, and acting as a solvent.

Solution

A mixture where one substance is dissolved in another.

Solvent

The substance that dissolves another substance in a solution; water is the universal solvent.

Solutes

The substances dissolved in a solvent.

Colloid

A mixture that is a heavy solution where solute molecules make the mixture opaque, such as milk or cream.

Suspension

A liquid mixture in which a heavier substance is suspended temporarily and settles out over time.

Dehydration synthesis

A chemical reaction that forms new molecules while creating water at the same time.

Hydrolysis

A reaction that breaks covalent bonds using water.

Salts

Compounds formed when ions bond through ionic bonding, which dissolve into separate ions in water.

Electrolytes

Ions capable of allowing the body to conduct electrical currents, important in nerve impulses and muscle contraction.

Acids

Substances that release hydrogen ions ($H^+$) when dissolved in solution.

Bases

Substances that release hydroxyl ions ($OH^-$) when dissolved in solution or bind hydrogen ions.

pH scale

A scale from $0$ to $14$ indicating acidity (closer to $0$) or alkalinity (closer to $14$), with $7$ being neutral.

Buffers

Substances used to prevent rapid changes in the pH of a solution.

Functional groups

Groups of atoms linked by covalent bonds that function as a unit and have predictable behaviors, such as hydroxyl, carboxyl, and amino groups.

Monomers

Individual units that bond together to form polymers.

Carbohydrates

Organic molecules made of carbon, hydrogen, and oxygen, serving as the main source of chemical energy.

Monosaccharides

Simple individual sugar molecules such as glucose, fructose, galactose, ribose, and deoxyribose.

Disaccharides

Sugars made of two monosaccharides, such as sucrose, lactose, and maltose.

Polysaccharides

Complex carbohydrates containing multiple monosaccharides, including starches, glycogen, and cellulose.

Lipids

Nonpolar, hydrophobic molecules made mostly of hydrocarbons that provide insulation and energy storage.

Triglyceride

The most common lipid in the human diet, containing a $3\text{-carbon}$ glycerol molecule and three fatty acids.

Saturated fats

Lipids with the maximal number of hydrogen atoms bound to carbon, usually solid or semisolid at room temperature.

Unsaturated fats

Lipids containing double bonds that are liquid at room temperature.

Phospholipids

Lipids containing a phosphorus "head," serving as important components of cellular membranes.

Cholesterol

A precursor used to make hormones and provide stability to the cell membrane.

Prostaglandins

Lipids derived from unsaturated fatty acids that play a role in inflammation.

Proteins

Molecules composed of amino acids linked by peptide bonds, providing structure, transport, and catalysis.

Amino acids

The monomers of proteins, consisting of an amino group, carboxyl group, and an R group; there are $20$ in total.

Peptide bonds

Bonds formed through dehydration synthesis that link amino acids together.

Primary structure

The specific sequence of amino acids in a protein chain.

Secondary structure

The folding of amino acid chains into an alpha-helix or beta-pleated sheet.

Tertiary structure

The additional folding that occurs between different regions of the same amino acid chain.

Quaternary structure

The interactions between two or more proteins, each with its own tertiary structure.

Denaturation

A change in the shape of a protein that results in it no longer being able to carry out its function.

Deoxyribonucleic acid ($DNA$)

A double-stranded, helical molecule that stores the genetic code using the bases adenine, cytosine, guanine, and thymine.

Ribonucleic acid ($RNA$)

A single-stranded molecule that participates in protein synthesis using the bases adenine, cytosine, guanine, and uracil.

Nucleotides

The monomers of nucleic acids, consisting of one or more phosphate groups, a sugar, and a nitrogen base.

Purines

The nitrogen base category that includes adenine and guanine.

Pyrimidines

The nitrogen base category that includes cytosine, thymine, and uracil.