Anatomy and Physiology - Chemical Basis of Life Vocabulary Flashcards

A set of vocabulary flashcards reviewing the key chemical concepts, subatomic particles, molecular bonds, reactions, and major classes of organic molecules from Chapter 2.

Matter

Anything that has mass and occupies space.

Atom

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

Proton

A subatomic particle located in the nucleus with a single positive (+) charge and a mass of approximately $1\text{ amu}$.

Neutron

A subatomic particle located in the nucleus with no charge and a mass of approximately $1\text{ amu}$.

Electron

A subatomic particle located in concentric clouds surrounding the nucleus with a single negative (-) charge and very low mass.

Atomic Number

The number of protons in an atom, which determines the identity of the element.

Valence Electrons

Electrons orbiting in the outermost electron shell that determine an atom's chemical bonding properties, reactivity, and relative stability.

Planetary Model

An atomic model depicting electrons in fixed orbits depicted as rings at precise distances from the nucleus, similar to planets orbiting the sun.

Electron Cloud Model

An atomic model showing electrons occupying a variety of locations where they are likely to be found over time, offering a more accurate representation of electron behavior.

Isotope

A variety of an element that differs only in the number of neutrons while retaining the same number of protons.

Ion

An atom that has a positive or negative electrical charge due to donating or accepting one or more electrons.

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.

Ionic Bond

A chemical bond formed by the electrical attraction between oppositely charged ions following the transfer of electrons from one atom to another.

Covalent Bond

A chemical bond formed when atoms share electrons to achieve a stable outer shell.

Non-Polar Covalent Bond

A covalent bond in which electrons are shared relatively equally, resulting in little or no charge separation.

Polar Covalent Bond

A covalent bond in which electrons are shared unequally, producing slightly positive and slightly negative regions on the molecule.

Hydrogen Bond

A relatively weak electrical attraction between a slightly positive hydrogen atom and a slightly negative atom of another molecule.

Thermal Stability

A property of water resulting from its high heat capacity, enabling it to absorb large amounts of heat with minimal temperature change.

Activation Energy

The energy input required to get a chemical reaction started.

Enzyme

A protein functioning as a biological catalyst that speeds up chemical reactions by lowering the required activation energy.

Monomer

A basic unit used as a building block to synthesize larger molecules.

Polymer

A large molecule composed of two or more chemically bonded monomers.

Dehydration Synthesis

A reaction that covalently joins two monomers together by removing a hydroxyl group from one and a hydrogen atom from the other, releasing a water molecule ($H_2O$).

Hydrolysis

A reaction that splits a covalent bond between monomers by adding a hydrogen atom to one part and a hydroxyl group to the other, requiring one molecule of water ($H_2O$).

Acid

A proton donor that dissociates in aqueous solution to release hydrogen ions ($H^+$).

Base

A proton acceptor that dissociates in aqueous solution to yield hydroxyl ions ($OH^-$) or accept hydrogen ions ($H^+$).

pH

A measure derived from the molarity of $H^+$ indicating the acidity or alkalinity of a solution, where $7.0$ is neutral, values below $7$ are acidic, and values above $7$ are basic.

Buffer

A chemical solution that resists changes in pH to maintain narrow homeostatic pH ranges within the body.

Four Major Classes of Organic Compounds

The four main classes of carbon-based molecules essential to human life: Carbohydrates, Lipids/Fats, Proteins, and Nucleic Acids.

Glycogen

A polysaccharide used for energy storage in human and animal tissues, found in the liver, muscle, brain, uterus, and vagina.

Starch

An energy-storage polysaccharide produced by plants that is digestible by humans.

Cellulose

A structural polysaccharide in plants that serves as an indigestible source of dietary fiber for humans.

Triglycerides

Lipids composed of one glycerol molecule covalently bound to three fatty acids via dehydration synthesis.

Phospholipids

Lipids composed of two fatty acids, glycerol, and a phosphate group, forming the fundamental structural component of cell membranes.

Cholesterol

The parent steroid ($85\%$ synthesized internally, $15\%$ obtained from diet) necessary for nervous system function, cell membrane integrity, and steroid hormone production.

Primary Structure

The linear sequence of amino acids in a protein, encoded directly by genes.

Secondary Structure

The coiled or folded shape of a protein held together by hydrogen bonds, forming either an alpha helix or a beta-pleated sheet.

Tertiary Structure

The three-dimensional folding of a protein into globular or fibrous shapes driven by hydrophobic-hydrophilic interactions and Van der Waals forces.

Quaternary Structure

The protein structural level formed by the interaction and combination of two or more individual polypeptide chains, such as in hemoglobin.

Antibodies

Proteins involved in immune recognition and protection that mark targets for destruction and stick to targets to prevent them from functioning.

Substrate

The specific chemical compound or reactant upon which an enzyme acts.

ATP (Adenosine Triphosphate)

A nucleotide composed of adenine, ribose, and three phosphate groups that functions as the primary energy currency of the cell.

Nucleotide

The monomer of nucleic acids, consisting of a nitrogenous base, a monosaccharide sugar, and one or more phosphate groups.

DNA vs. RNA

Comparison showing that DNA contains deoxyribose, thymine (T), is double-stranded, and stores genetic instructions, whereas RNA contains ribose, uracil (U), is single-stranded, and carries instructions to synthesize proteins.