BLG143: BIOLOGY I - Water and Carbon: The Chemical Basis of Life

These flashcards cover key concepts related to water and carbon as the chemical basis of life, as well as fundamental principles of chemistry relevant to biology.

Chemical Evolution

Leading hypothesis for the origin of life on Earth involving simple molecules forming complex carbon-containing molecules.

Atoms

The basic units of matter; four atoms make up 96% of matter in organisms: hydrogen, carbon, nitrogen, oxygen.

Protons

Positively charged particles found in the nucleus of an atom.

Neutrons

Neutral particles located in the nucleus of an atom.

Electrons

Negatively charged particles found in orbitals surrounding the nucleus of an atom.

Atomic Number

The number of protons in the nucleus of an atom.

Mass Number

The total number of protons and neutrons in an atom.

Covalent Bonds

Bonds formed when unpaired valence electrons are shared between two atoms.

Valence Electrons

Electrons in the outermost shell of an atom that determine its bonding behavior.

Polar Covalent Bonds

Covalent bonds where electrons are shared unevenly between two atoms.

Nonpolar Covalent Bonds

Covalent bonds where electrons are shared equally between two atoms.

Ionic Bonds

Bonds that form when electrons are transferred from one atom to another, resulting in charged ions.

Hydrophilic

Substances that are water-loving and dissolve in water.

Hydrophobic

Substances that are water-fearing and do not dissolve in water.

Cohesion

Binding between like molecules; water's high surface tension is due to cohesion.

Adhesion

Binding between unlike molecules, such as water binding to glass or plastic.

Hydrogen Bonds

Weak electrical attractions between a hydrogen atom and a more electronegative atom.

Acids

Substances that donate protons (H+) in solution.

Bases

Substances that accept protons (H+) in solution.

pH Scale

A measure of the acidity or basicity of a solution; ranges from 0 to 14.

Chemical Equilibrium

The state where the rates of forward and reverse reactions are equal.

Potential Energy

Stored energy that has the potential to do work.

Kinetic Energy

The energy of movement; in molecules, this is thermal energy.

Thermal Energy

The energy associated with the temperature of a substance.

First Law of Thermodynamics

Energy cannot be created or destroyed; it can only be transformed or transferred.

Spontaneous Reactions

Chemical reactions that occur without external influence and do not require added energy.

Entropy

A measure of disorder; in spontaneous reactions, entropy generally increases.

Organic Molecules

Compounds that contain carbon bonded to other elements.

Stanley Miller Experiment

Re-creation of chemical evolution showing that complex organic molecules can form from simple molecules under early Earth conditions.

Hydronium Ion

The ion formed when water dissociates, represented as H3O+.

Equilibrium Constant

A value that expresses the ratio of products to reactants at equilibrium.

Molecular Shape

The specific three-dimensional arrangement of the atoms in a molecule.

Chemical Energy

Potential energy stored within chemical bonds.

Solution

A homogeneous mixture of solute dissolved in a solvent.

Solvent

The substance that dissolves a solute to form a solution.

Nucleus

The central part of an atom containing protons and neutrons.

Electron Shells

Layers around the nucleus of an atom where electrons reside.

Valence Shell

The outermost shell of electrons in an atom.

Capillary Action

The ability of a liquid to flow in narrow spaces without external forces.

pH of Water

The pH value of pure water is 7, indicating a neutral solution.

Buffer

A solution that minimizes changes in pH when an acid or base is added.

Chemical Bonds

Attractive forces that hold atoms together in a molecule.

Chemical Reaction

A process that involves the rearrangement of atoms to form new substances.

Hydrogen Ion

A positively charged ion (H+) that is central to acid-base chemistry.

Polar Molecule

A molecule with an uneven distribution of charge, resulting in partial positive and negative ends.

Chemical Properties

Characteristics of a substance that become evident during a chemical reaction.

Ionic Compound

A compound formed by ionic bonds, consisting of cations and anions.

Intermolecular Forces

Forces of attraction or repulsion between neighboring particles.