OnRamps Biology Learning Modules 3 and 4 Flashcards

Vocabulary flashcards covering chemical bonding, intermolecular forces, physical properties of water, organic functional groups, and carbon isomerism.

Molecule

A stable grouping of two or more atoms held together by chemical bonds.

Chemical Compound

A molecule made up of two or more atoms of different elements, such as water ($H_2O$) or methane ($CH_4$).

Ion

An atom or group of atoms that carries an electrical charge due to gaining or losing one or more electrons.

Cation

A positively charged ion formed when an atom donates one or more valence electrons, such as $K^+$ or $Na^+$.

Anion

A negatively charged ion formed when an atom accepts one or more electrons, such as fluoride ($F^-$) or chloride ($Cl^-$).

Ionic Bond

An ongoing, close electrical attraction between oppositely charged cations and anions, such as sodium ($Na^+$) and chloride ($Cl^-$).

Electrolytes

Dissolved ions in biological fluids that conduct electrical charges necessary for muscle, heart, and brain functions.

Covalent Bond

A strong chemical bond formed when two atoms share pairs of valence electrons in a mutually stabilizing relationship.

Nonpolar Covalent Bond

A covalent bond in which shared electrons are distributed equally between atoms, resulting in no region of partial charge.

Polar Covalent Bond

A covalent bond formed when atoms share electrons unequally due to differences in electronegativity, creating partial positive ($\delta+$) and partial negative ($\delta-$) charges.

Hydrogen Bond

A weak intermolecular attraction formed when a weakly positive hydrogen atom bonded to an electronegative atom (like $O$, $N$, or $F$) is attracted to another electronegative atom.

Intermolecular Forces (IMFs)

Attractive forces that exist between separate atoms, molecules, or ions of a substance due to electrostatic phenomena.

Intramolecular Forces

Forces within a molecule that hold its constituent atoms together, such as covalent or ionic bonds.

Van der Waals Forces

All attractive forces between neutral atoms and molecules, encompassing dispersion forces, dipole-dipole attractions, and hydrogen bonding.

London Dispersion Force

A temporary, weak intermolecular attraction present in all condensed phases caused by instantaneous, fluctuating dipoles inducing dipoles in neighboring species.

Polarizability

The ease or difficulty with which an external electrostatic charge can distort an atom's or molecule's electron cloud.

Setae

Hundreds of thousands of tiny hairs on a gecko's toes that branch into microscopic spatulae to maximize surface area for van der Waals adhesion.

Spatulae

The flat, triangular microscopic tips at the ends of gecko setae that facilitate strong surface adhesion via cumulative dispersion forces.

Dipole-Dipole Attraction

An electrostatic attraction between the partially positive end of one polar molecule and the partially negative end of another polar molecule, such as in $HCl$.

Purines

Double-ringed nitrogenous bases in nucleic acids, specifically adenine ($A$) and guanine ($G$).

Pyrimidines

Single-ringed nitrogenous bases in nucleic acids, specifically cytosine ($C$) and thymine ($T$).

Hydrophilic

Describing polar or charged substances that interact readily with or dissolve in water.

Hydrophobic

Describing nonpolar molecules, such as fats and oils, that do not dissolve in water and are repelled by polar water molecules.

Specific Heat Capacity

The amount of heat $1\,\text{g}$ of a substance must absorb or lose to change its temperature by $1\,^\circ\text{C}$ ($1\,\text{cal}$ for water).

Heat of Vaporization

The amount of heat energy required to transform $1\,\text{g}$ of a liquid substance into a gas ($586\,\text{cal}$ for water).

Sphere of Hydration

A surrounding cluster of oriented water molecules that keeps dissolved ions or polar solutes dispersed in solution.

Cohesion

The intermolecular attraction between like molecules, such as water molecules binding to each other via hydrogen bonds.

Surface Tension

The capacity of a liquid surface to resist rupturing when subjected to tension or stress due to cohesive forces.

Adhesion

The attractive force between water molecules and other distinct polar or charged surfaces.

Capillary Action

The upward movement of water within narrow tubes caused by adhesive forces to charged container walls overcoming internal cohesive forces.

pH Scale

A logarithmic scale ranging from $0$ to $14$ measuring the concentration of hydrogen ions ($H^+$) in a solution, calculated as $-\log_{10}([H^+])$.

Acid

A substance that increases the concentration of hydrogen ions ($H^+$) in a solution, lowering the pH below $7.0$.

Base

A substance that decreases hydrogen ion ($H^+$) concentration in a solution (often by providing hydroxide ions, $OH^-$), raising the pH above $7.0$.

Buffer

A chemical system, such as carbonic acid ($H_2CO_3$) and bicarbonate ($HCO_3^-$) in human blood, that absorbs excess $H^+$ or $OH^-$ to stabilize pH.

Functional Groups

Specific arrangements of atoms attached to a carbon backbone that confer defined chemical characteristics and biological properties to organic molecules.

Substituted Hydrocarbons

Molecules in which one or more carbon atoms in the hydrocarbon chain or ring backbone are replaced by other elements such as nitrogen or oxygen.

Hydroxyl Group

A polar, hydrophilic functional group composed of an oxygen atom bonded to a hydrogen atom ($-OH$).

Sulfhydryl Group

A polar functional group containing a sulfur atom bonded to a hydrogen atom ($-SH$).

Methyl Group

A nonpolar, hydrophobic functional group consisting of a carbon atom bonded to three hydrogen atoms ($-CH_3$).

Carbonyl Group

A polar functional group characterized by a central carbon atom double-bonded to an oxygen atom ($-C=O$).

Carboxyl Group

An acidic, charged functional group ($-COOH$) that ionizes in solution to release $H^+$ ions, forming $-COO^-$.

Amino Group

A basic, charged functional group ($-NH_2$) containing nitrogen that accepts $H^+$ from solution to form $-NH_3^+$.

Phosphate Group

An acidic, complex functional group containing phosphorus ($-PO_4^{2-}$) that ionizes to release $H^+$ ions into solution.

Methane Geometry

A three-dimensional tetrahedral structure formed by a central carbon atom bonded to four hydrogen atoms with bond angles of $109.5^\circ$.

Aliphatic Hydrocarbons

Hydrocarbons consisting of linear chains or non-aromatic rings of carbon atoms joined by single or double covalent bonds.

Aromatic Hydrocarbons

Hydrocarbons containing closed rings of carbon atoms with alternating single and double bonds, such as benzene.

Isomers

Molecules that share the exact same chemical formula but differ in the spatial arrangement, bond structure, or placement of their constituent atoms.

Structural Isomers

Isomers that differ in the covalent arrangement of their constituent atoms and bonds, such as butane and isobutane.

Geometric Isomers

Isomers that have identical covalent bonds but differ in the spatial orientation of groups around a rigid carbon-carbon double bond (cis vs trans).

Enantiomers

Molecules that are non-superimposable mirror images of each other around a central carbon atom bonded to four different groups.

Saturated Fats

Triglycerides containing fatty acid chains with no carbon-carbon double bonds, allowing tight packing into solid form at room temperature.

Unsaturated Fats

Triglycerides containing fatty acid chains with one or more carbon-carbon double bonds, preventing tight packing and remaining liquid at room temperature in the cis configuration.