Body Chemistry

What is matter made of?

atoms

what do chemical characteristics determine?

physiology at the molecular and cellular levels

What do atoms join together to form?

chemicals with different characteristics

subatomic particles

protons, neutrons, electrons

proton

positive charge

neutron

neutral charge

electron

negative charge

1 mass unit

protons and neutrons

low mass

electron

Atomic Structure

atomic number, nucleus, electron cloud

atomic number

number of protons

nucleus

contains protons and neutrons

electron cloud

contains electrons

The hydrogen nucleus consists of

a single proton

what is the mass number of hydrogen?

1

Deuterium nucleus

has one proton and one neutron

The mass number of deuterium is

2

Tritorium nucleus

one proton and two neutrons

Mass number of tritium

3

Oxygen (65)

A component of water and other compounds; oxygen gas is essential for respiration

carbon (18.6)

found in all organic molecules

hydrogen (9.7)

A component of water and most other compounds in the body

nitrogen (3.2)

Found in proteins, nucleic acids, and other organic compounds

calcium (1.8)

Found in bones and teeth; important for membrane function, nerve impulses, muscle contraction, and blood clotting

phosphorus (1)

Found in bones and teeth, nucleic acids, and high-energy compounds

potassium (0.4)

Important for proper membrane function, nerve impulses, and muscle contraction

Sodium (0.2)

important for blood volume, membrane function, nerve impulses, and muscle contraction

chlorine (0.2)

important for blood volume, membrane function, and water absorption

magnesium (0.06)

cofactor for many enzymes

sulfur (0.04)

Found in many proteins

Iron (0.007)

essential for oxygen transport and energy capture

Iodine (0.0002)

A component of hormones of the thyroid gland

trace elements

Silicon, fluorine, copper, manganese, zinc, selenium, cobalt, molybdenum, cadmium, chromium, tin, aluminum, boron, and vanadium

function of trace elements

cofactors of enzymes

how are elements determined?

by the atomic number of an atom

most basic chemicals

elements

Isotopes

Atoms of the same element that have different numbers of neutrons

mass number

equal to the total number of protons and neutrons of the atom

Radioisotopes

Isotopes that have unstable nuclei and undergo radioactive decay.

atomic weight

Average of the mass numbers of all isotopes

moles

unit of measurement represented by "n"

Electrons in the electron cloud

determine the reactivity of an atom

electron cloud shells

The area around the nucleus where the electrons are located. Each level can only hold a certain number of electrons.

lower shells

fill first

valence shell

outermost electron shell

what determines bonding

valence shell

chemical bonds

involve the sharing, gaining, and losing of electrons in the valence shell

Three major types of chemical bonds

ionic bonds, covalent bonds, hydrogen bonds

ionic bond

attraction between cations and anions

covalent bond

A chemical bond formed when two atoms share electrons

hydrogen bond

weak attraction between a hydrogen atom and another atom

electron donor

cation

electron acceptor

anion

chemical bonds form

molecules or compounds

molecules

two or more atoms joined by strong bonds

compounds

atoms of different elements bond together in specific proportions

compounds are molecules

but not all molecules are compounds

Is H2O a compound or a molecule?

both

is h2 a compound or molecule?

molecule

ionic bonds

one or more electrons are transferred from one atom to another

sodium chloride crystal

Large numbers of sodium and chloride ions form a crystal of sodium chloride (table salt).

covalent bonds

Bonds created by sharing electrons with other atoms.

single covalent bond

sharing one pair of electrons

double covalent bond

sharing two pairs of electrons

triple covalent bond

sharing three pairs of electrons

nonpolar covalent bond

a covalent bond in which the electrons are shared equally by the two atoms

polar covalent bond

A covalent bond in which electrons are not shared equally

Is water polar or non-polar?

polar

What causes surface tension?

hydrogen bonds between H2O molecules

states of matter

solid, liquid, gas

solid

Definite shape and volume

liquid

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

gas

A state of matter with no definite shape or volume

What happens in a chemical reaction?

either new bonds are formed or existing bonds are broken

reactants

materials going into a reaction

products

materials coming out of a reaction

Metabolism

all chemical reactions occurring in the body

types of chemical reactions

synthesis, decomposition, single replacement, double replacement, combustion

decomposition reaction (catabolism)

breaks chemical bonds AB-->A+B

Hydrolysis example

sucrose + water --> glucose + fructose

Synthesis Reaction (Anabolism)

forms chemical bonds; A + B > AB

dehydration synthesis (condensation reaction)

The formation of a complex molecule by the removal of a water molecule

exchange reaction

Involves decomposition first, then synthesis

reversible reaction

A+B-->AB

reversible reaction

a chemical reaction in which the products re-form the original reactants

activation energy

Energy needed to get a reaction started

Enzymes (catalysts)

lower the activation energy of chemical reactions

exergonic (exothermic)

produce more energy than they use

endergonic (endothermic)

use more energy than they produce

inorganic compounds

Molecules not based on carbon and hydrogen

organic compounds

Molecules based on carbon and hydrogen

How much of body weight is water?

2/3

solution

uniform mixture of two or more substances

Solvent

A liquid substance capable of dissolving other substances

solute

A substance that is dissolved in a solution.

colloid

a solution containing dispersed proteins or other large molecules

example of colloid

blood plasma

suspension

solute particles are very large, settle out, and may scatter light

example of suspension

whole blood

pH

hydrogen ion concentration