Chemical Level of Organization

Atom

smallest stable unit of matter

Proton

A subatomic particle that has a positive charge and that is found in the nucleus of an atom

Neutron

A subatomic particle that has no charge and that is found in the nucleus of an atom

Electron

A subatomic particle that has a negative charge

Electron cloud

a region around the nucleus of an atom where electrons are likely to be found

Nucleus

The center of an atom, containing the protons and neutrons

Electron shell

2 dimensional representation of fixed orbits around the nucleus where electrons are located

Isotope

An atom with the same number of protons and a different number of neutrons from other atoms of the same element.

Mass number

Number of protons and neutrons

Atomic mass unit

one twelfth the mass of a carbon-12 atom

Atomic weight

Average of the mass numbers of all isotopes

Atomic mass

actual mass of a specific isotope, not the approximation

Matter

Anything that has mass and takes up space

Mass

A measure of the amount of matter in an object

Atomic number

the number of protons in the nucleus of an atom

Element

A pure substance made of only one kind of atom

Mole

quantity of any element with a weight in grams equal to that element's atomic weight; always contains 6.023 x 10^23 atoms (Avogadro's number)

Molecular weight

the sum of the atomic weights of all the atoms in a molecule

13 Principal elements of Human Body

oxygen, carbon, hydrogen, nitrogen, calcium, phosphorus, potassium, sodium, chlorine, magnesium, sulfur, iron, iodine

Valence shell

The outermost energy shell of an atom, containing the valence electrons involved in the chemical reactions of that atom.

Reactive elements

Valence shells are not full and are unstable

Inert elements

have complete valence shells and are stable; do not readily participate in chemical reactions

Ion

A charged atom

Cation

A positively charged ion

Anion

A negatively charged ion

Chemical bond

interactions that stabilize the outer energy levels of atoms

Molecule

two or more atoms held together by covalent bonds

Compound

A substance made up of atoms of two or more different elements joined by chemical bonds

Ionic bonds

Formed when one or more electrons are transferred from one atom to another

Covalent bond

A chemical bond that involves sharing a pair of electrons between atoms in a molecule

Polar molecule

molecule with an unequal distribution of charge, resulting in the molecule having a positive end and a negative end

Non-polar covalent bond

a covalent bond in which the bonding electrons are shared equally by the bonded atoms, resulting in a balanced distribution of electrical charge

Hydrogen bonding in water

Water molecules are polar and hydrogen bonds form between them; partial negative charge of oxygen attracted to partial positive charge on hydrogen

Surface tension

the force that acts on the surface of a liquid and that tends to minimize the area of the surface

Solid

A form of matter that has a definite shape and volume

Liquid

A state of matter that has no definite shape but has a definite volume.

Gas

A state of matter with no definite shape or volume

Reactants

A starting material in a chemical reaction

Products

The elements or compounds produced by a chemical reaction.

Metabolism

All of the chemical reactions that occur within an organism

Kinetic energy

energy of motion

Potential energy

stored energy

Heat

causes increase in random molecular motion

Decomposition reaction

reaction which breaks a larger molecule into smaller fragments

Hydrolysis

Breaking down complex molecules by the chemical addition of water

Catabolism

Metabolic pathways that break down molecules, releasing energy.

Synthesis reaction

a reaction in which two or more substances combine to form a new compound

Dehydration synthesis

Condensation reaction where molecules are connected by loss of a water molecule.

Anabolism

Metabolic pathways that construct molecules, requiring energy. Includes all synthesis reactions

Exchange reactions

part synthesis and part decomposition; two larger molecules are split apart, the parts are shuffled around and reformed into two new large molecules

Equilibrium

a state in which opposing forces or influences are balanced.

Function of enzymes

speed up chemical reactions, decrease the activation energy of a reaction

Catalyst

substance that speeds up the rate of a chemical reaction but is not permanently changed or consumed; enzymes are catalysts

Exergonic reaction

Reaction that proceeds with a net release of free energy.

Endergonic reaction

Reaction that absorbs free energy from its surroundings.

Metabolites

molecules made or broken down in the body

Nutrients

Essential substances in food that your body needs to grow, to repair itself, and to supply you with energy

Organic compounds

Compounds that contain carbon and hydrogen as primary ingredients

Inorganic compounds

Compounds that do not contain carbon as a primary component

Important properties of water

lubrication, chemical reactant, high heat capacity, solubility

Ionization (dissociation)

a compound separates into its ions when added to water - an aqueous solution

Is water polar or non-polar?

Water is a polar molecule

Electrolytes

soluble inorganic substances whose ions will conduct an electrical current in solution

Cations move toward the _________ side of an electrical field

negative

Anions move toward the ________ side of an electrical field

positive

Electrical currents are essential to what basic physiologic processes?

muscle contraction and nerve function

Electrolyte levels are regulated by what organ systems?

1. Urinary system (kidney)

2. Digestive system

3. Skeletal system

Colloid

A mixture containing dispersed proteins or other large particles that do not settle out.

Suspension

A mixture in which particles can be seen and easily separated by settling or filtration

Hydrophobic

Water fearing, substances that do not interact with water

HYdrophilic

water loving. substances that easily mix with water.

pH

hydrogen ion concentration in substance

pH>7

basic/alkaline

pH=7.0

neutral

pH<7

acidic

Normal pH range of blood

7.35-7.45

Acidosis

pH below 7.35

Alkalosis

Blood pH above 7.45

Acid

A substance that increases the hydrogen ion concentration of a solution.

Base

A substance that decreases the hydrogen ion concentration in a solution.

Salt

An ionic compound with a cation other than hydrogen and an anion other than hydroxide

Buffer

A substance that stabilizes the pH of a solution by removing or replacing hydrogen ion

Amino group

NH2

Carboxyl group

COOH

Hydroxyl group

OH-

Phosphate group

PO4

Carbohydrates

the starches and sugars present in foods; made of carbon, hydrogen & oxygen (1:2:1)

Isomer

Compounds with the same molecular formula but different 3D structures.

Monosaccharides

simple sugars (glucose, fructose)

Disaccharide

A double sugar, consisting of two monosaccharides joined by dehydration synthesis.

Polysaccharides

Carbohydrates that are made up of more than two monosaccharides; examples: cellulose, starches, glycogen

The only carbohydrate that can be stored in large quantities

glycogen

Lipids

Energy-rich organic compounds, such as fats, oils, and waxes, that are made of carbon, hydrogen, and oxygen.

Fatty acids

One end carboxyl group and the other a hydrocarbon tail

saturated fatty acid

A fatty acid in which all carbons in the hydrocarbon tail are connected by single bonds, thus maximizing the number of hydrogen atoms that can attach to the carbon skeleton.

unsaturated fatty acid

A fatty acid possessing one or more double bonds between the carbons in the hydrocarbon tail. Such bonding reduces the number of hydrogen atoms attached to the carbon skeleton.

Glycerides

fatty acids attached to a glycerol molecule

Eicosanoids

lipids derived from arachidonic acid

Prostaglandins

Type of eicosanoid, released by damaged tissue that stimulates nerve endings & produces pain

Steroids

lipids characterized by a carbon skeleton consisting of four fused rings (cholesterol molecule)