Bio111: Water and Carbon

Hydrogen Bond

weak attraction between a hydrogen atom that is part of a polar covalent bond and another electronegative atom like oxygen or nitrogen

Adhesion

attraction between molecules of different substances (like water and glass)

Cohesion

an attraction between molecules of the same substance (like water and water creating surface tension)

Polar

Molecule with partial charges due to the presence of an electronegative atom like oxygen, nitrogen, phosphorous, or sulfur. Mixes with water.

pH

a measure of hydrogen ion (H+) concentration; as pH increases, H+ decreases

Acids

substances that release hydrogen ions (H+) when dissolved in water; cause pH to decrease

Base

A substance that decreases the hydrogen ion concentration in a solution, while increasing the hydroxide ion (OH-) concentration.

Buffer

weak acid or base that can react with strong acids or bases to help prevent sharp, sudden changes in pH

Ion

An atom or group of atoms that has a positive or negative charge due to the gain or loss of electrons.

Ionic bond

A chemical bond resulting from the attraction between oppositely charged ions.

Isomers

Compounds with the same formula but different structures.

Dehydration Synthesis (Condensation)

A chemical reaction in which two molecules covalently bond to each other with the removal of a water molecule.

Hydrolysis

A chemical process that splits a molecule by adding water.

Monomer

small chemical unit that makes up a polymer

Polymer

molecules composed of many monomers; makes up macromolecules

Hydrophilic

water loving, polar molecule

Hydrophobic

water hating, nonpolar molecule

Covalent Bond

A chemical bond formed when two atoms share electrons

Carbon

atom with 4 valence electrons that forms the backbone of all organic molecules

Nonpolar

Molecules like oil in which all atoms have similar electronegativity and the electron distribution is equal between atoms in a covalent bond (i.e. C-H, C-C, O-O)

Transpiration

The process where plants absorb water through the roots and then give off water vapor through pores in their leaves

Functional Groups

the components of organic molecules that are most commonly involved in chemical reactions

Spontaneous Reaction

occurs naturally and favors the formation of products at the specified conditions without a constant input of outside energy

Second Law of Thermodynamics

When energy is changed from one form to another, some useful energy is always degraded into lower quality energy (usually heat), which increases the entropy of the universe

Surface Tension

A measure of how difficult it is to stretch or break the surface of a liquid

Specific Heat

The amount of energy required to raise the temperature of 1 gram of a substance by 1 degree celcius; water has a high specific heat (it requires a lot of energy to change its temperature)

Solvent

A liquid substance capable of dissolving other substances; water is often called the "universal solvent" but only dissolves other POLAR substances

First Law of Thermodynamics

Energy can be transferred and transformed, but it cannot be created or destroyed.

Potential Energy

Energy that is stored and held in readiness (i.e. in a chemical bond)

Kinetic Energy

energy of motion (i.e. thermal energy, the movement of atoms due to heat)