The Chemistry of Life

Flashcards about water chemistry, elements, and bonds in biology.

Hydrophilic

Substances with an attraction to water.

Hydrophilic phospholipid heads

Phospholipid heads that are attracted to water.

Hydrophobic

Substances that don't have an attraction to water.

Hydrophobic phospholipid tails

Phospholipid tails that repel water.

Hydrogen Bonds

Attraction between positive and negative.

Hydrophobic and Hydrophilic interactions

Interactions with H2O.

Covalent bonds

Sharing electrons.

Nonpolar covalent bond

Pair of electrons shared equally by 2 atoms.

Polar covalent bonds

Pair of electrons shared unequally by 2 atoms.

Electronegativity

Oxygen has stronger “attraction” for the electrons than hydrogen.

Cohesion

H bonding between H2O molecules; water is 'sticky'.

Adhesion

H bonding between H2O & other substances.

Solutes

Substances that dissolve in a solvent.

Solvent

Polar H2O molecules surround + & – ions; dissolves solutes, creating solutions.

Ionization of Water

H+ splits off from H2O, leaving OH–.

pH Scale

How acid or basic a solution is.

Buffers

Reservoir of H+; donate H+ when [H+] falls; absorb H+ when [H+] rises.

Hydrophilic

Substances that have an attraction to water, often forming hydrogen bonds with it.

Hydrophilic phospholipid heads

The phosphate-containing regions of phospholipids that are attracted to water, allowing them to interact with the aqueous environment.

Hydrophobic

Substances that do not have an attraction to water, often repelling it.

Hydrophobic phospholipid tails

The long, fatty acid chains of phospholipids that repel water and avoid interacting with it.

Hydrogen Bonds

The weak attractions that occur between a hydrogen atom covalently bonded to an electronegative atom and another electronegative atom.

Hydrophobic and Hydrophilic interactions

The behavior of molecules in an aqueous environment where hydrophilic substances interact with water while hydrophobic substances aggregate away from it.

Covalent bonds

Chemical bonds formed by the sharing of one or more pairs of electrons between atoms.

Nonpolar covalent bond

A type of covalent bond where the electrons are shared equally between the two atoms, resulting in no charge difference across the bond.

Polar covalent bonds

Covalent bonds where the electrons are shared unequally, leading to partial positive and negative charges on the atoms involved.

Electronegativity

The tendency of an atom to attract electrons in a bond, often higher in elements such as oxygen compared to hydrogen.

Cohesion

The intermolecular force between water molecules caused by hydrogen bonding, making water 'sticky' and enabling surface tension.

Adhesion

The attraction between water molecules and other substances, which can lead to capillary action.

Solutes

Substances that are dissolved in a solvent to form a solution; examples include salts, sugars, and gases.

Solvent

A substance, typically a liquid, that dissolves a solute, resulting in a solution; water is a common solvent due to its polarity.

Ionization of Water

The process by which water (H2O) dissociates into hydrogen ions (H+) and hydroxide ions (OH-), establishing an equilibrium.

pH Scale

A logarithmic scale used to specify the acidity or basicity of an aqueous solution, ranging from 0 (acidic) to 14 (basic), with 7 being neutral.

Buffers

Substances that help maintain a stable pH in a solution by either donating H+ ions when the concentration falls or absorbing them when the concentration rises.

Hydrophobic Effect

The tendency of nonpolar substances to aggregate in aqueous solutions to minimize their exposure to water.

Surface Tension

The cohesive force at the surface of a liquid, created by hydrogen bonding in water, which allows it to resist external force.

Hydration Shell

The sphere of water molecules that surrounds dissolved ions or molecules in a solution, stabilizing them.

Colloid

A mixture in which very small particles are dispersed throughout a liquid without settling out.

Osmosis

The diffusion of water across a selectively permeable membrane, moving from an area of lower solute concentration to an area of higher concentration.

Tonicity

The ability of a solution to change the shape or tone of cells by altering their internal water volume, categorized as isotonic, hypertonic, or hypotonic.