anything that takes up space and has mass, made up of atoms

the smallest stable units of matter, join together to form chemicals with different characteristics

determine physiology on the molecular and cellular level

Proton - Positive charge, 1 mass unit
Neutron - Neutral, 1 mass unit
Electron - Negative charge, low mass

Nucleus - Contains protons and neutrons
Electron cloud - contains electrons

number of protons

number of protons plus neutrons

exact mass of all particles (daltons)
1 Dalton (Da) = 1.66 x 10-24grams (g) = the mass of
one proton or neutron

2 or more elements with equal numbers of protons but different numbers of neutrons

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

1. Ionic bonds 2. Covalent bonds 3. Hydrogen bonds

Attraction between cations (electron donor) and
anions (electron acceptor) are atoms with positive or negative charge

Formed between atoms that share electrons
Strong electron bonds involving shared electrons
Non polar covalent bonds: equal sharing of electrons
Polar covalent bonds: unequal sharing of electrons

Weak polar bonds based on partial electrical attractions

Ion or molecule that contain unpaired electrons in the outermost shell.
Extremely Reactive
typically enter into destructive reactions
Damage/destroy vital compounds

Attractive force between polar covalent molecules
•Weak force that holds molecules together
•Hydrogen bonds between H2O molecules cause surface tension

Two or more atoms joined by strong bonds

Two or more atoms OF DIFFERENT ELEMENTS joined by strong or weak bonds Compounds are all molecules, but not all molecules are compounds

the capacity to do work

a change in mass or distance

1. Kinetic energy 2. Potential energy 3. Chemical energy

energy of motion

stored energy

potential energy stored in chemical bonds

cells cannot capture it or use it for work

•Decomposition Reaction (Catabolism)
– Breaks chemical bonds
– AB -> A + B
– Hydrolysis A-B+H2O -> A-H + HO-B
•Synthesis Reaction (Anabolism)
–Forms chemical bonds
–A + B->AB
–Dehydration synthesis (condensation reaction)
•Exchange Reaction
-AB + CD->AD + CB
-Involves decomposition first, then synthesis
•Reversible reaction
-AB + CD-><-AD + CB
-At equilibrium the amounts of chemicals do not
change even though the reactions are still occurring

Reactants:
–
materials going
into
a reaction
•
Products:
–
materials coming
out
of a reaction
•
Enzymes:
–
proteins that lower the activation energy of a
reaction

materials going into a reaction

materials coming out of a reaction

proteins that lower the activation energy of a
reaction are protein catalysts that lower the activation energy of reactions most chemical reactions that sustain life cannot occur unless the right enzymes are present

the amount of energy needed to get a reaction started

produce more energy than they use heat will be the by product

use more energy than they produce

molecules based mostly on carbon and hydrogen (Carbohydrates, proteins, lipids, and nucleic acids)

molecules not based mostly on carbon and
hydrogen (Carbon dioxide, oxygen, water, and inorganic acids,bases, and salts)

1.nutrients 2. metabolites

essential molecules obtained from food

molecules made or broken down in the body

Water accounts for up to two-thirds of your total body weight

1. Solubility 2. Reactivity 3. high heat capacity 4. Lubrication

water’s ability to dissolve a solute in a solvent
to make a solution

most body chemistry uses or occurs in water

water’s ability to absorb and retain heat

to moisten and reduce friction

Polar water molecules form hydration spheres
around ions and small polar molecules to keep them in solution

Hydrophilic and hydrophobic compounds

hydro = water,
philos = loving
Interacts with water Includes ions and polar molecules

phobos = fear
Does NOT interact with water
Includes non polar molecules, fats, and oils
Electrolytes and body fluids

are inorganic ions that conduct electricity in solution Electrolyte imbalance seriously disturbs vital body functions

A solution of very large organic molecules
For example, blood plasma

A solution in which particles settle (sediment)
For example, whole blood

The amount of solute in a solvent (mol/L, g/L)

The concentration of hydrogen ions (H+) in a
solution

Unbound protons
•Have important biological effects
•Form when water ionizes:
H2O -> H+ + OH-
Hydrogen Ion (or Proton) Water Hydroxide Ion

a balance of H+ and OH—
–pure water = 7.0

pH lower than 7.0
– high H+ concentration
- low OH— concentration

pH higher than 7.0
– low H+ concentration
- high OH— concentration

Has an inverse relationship with H+ concentration:
–more H+ ions mean lower pH, less H+ ions mean
higher pH

Excess H+ ions (low pH
–damages cells and tissues
–alters proteins
–interferes with normal physiological functions

Excess OH— ions (high pH)
–Uncontrollable and sustained skeletal muscle contraction

salts and buffers

–positive or negative ions in solution
–contain no H+ or OH
—(NaCl)

–weak acid/salt compounds
–neutralizes either strong acid or strong base
Minimizes extreme shifts in pH
•Partnership between weak acids and bases, which work as pair to counter shifts in pH
•Example: Carbonic Acid
-Bicarbonate Buffer System
–When blood pH rises, carbonic acid dissociates to form bicarbonate and H+H2C03----> HC03-+ H+–
When blood pH drops, bicarbonate binds H+ to form carbonic acid HC03-+ H+-----> H2C03

-Contain H, C, and usually O
-Are covalently bonded
-Contain functional groups that determine chemistry: Carbohydrates Lipids Proteins (or amino acids) Nucleic acids

Contain carbon, hydrogen, and oxygen in a 1:2:1
ratio

Simple sugars with 3 to 7 carbon atoms
Glucose, fructose, galactose

Two simple sugars condensed by dehydration synthesis Sucrose, maltose

Many monosaccharides condensed by dehydration synthesis Glycogen, starch, cellulose

Structural Formula:
•Straight
-chain form
•Ring from
•3-D
Isomers: Glucose vs. Fructose:
-Same chemical formula but different shape

made and stored in muscle cells

-Mainly hydrophobic molecules such as fats, oils,
and waxes
-Made mostly of carbon and hydrogen atoms (1:2),
and some oxygen

Fatty acids
Eicosanoids
Glycerides
Steroids
Phospholipids and glycolipids

-Long chains of carbon and hydrogen with a
carboxyl group (COOH) at one end
-Are relatively nonpolar, except the carboxyl group
-Fatty acids may be:
Saturated with hydrogen (single covalent bonds)
Unsaturated (one or more double bonds)
Lauric acid demonstrates two structural characteristics common to all fatty acids:
a long chain of carbon atoms and a carboxyl
group (—COOH) at one end

one double bond

two or more double bonds

derived from the fatty acid called arachidonic acid
Used for cellular communication Never burned for energy

Active in immune system Used by cells to signal injury

Local hormones, short
-chain fatty acids Used for cell-to-cell signaling to coordinate events

Fatty acids attached to a glycerol molecule Triglycerides are the three fatty
-acid tails Also called triacylglycerols or neutral fats

1.Energy source 2.Insulation 3.Protection

Four rings of carbon and hydrogen with an assortment of functional groups

1.Cholesterol 2.Estrogens and testosterone
3.Corticosteroids and calcitriol 4.Bile salts

Component of plasma (cell) membranes

Sex hormones

Tissue metabolism and mineral balance

Derived from steroids Processing of dietary fats

attached to either a phosphate group (phospholipid) or a sugar (glycolipid)
Generally, both have hydrophilic heads and
hydrophobic tails and are structural lipids,
components of plasma (cell) membranes

Are the most abundant and important organic molecules Contain basic elements
-Carbon (C), hydrogen (H), oxygen (O), and nitrogen (N)
-Basic building blocks
-20 amino acids

1.Support •Structural proteins
2.Movement •Contractile proteins
3.Transport •Transport (carrier) proteins
4.Buffering •Regulation of pH
5.Metabolic Regulation •Enzymes
6.Coordination and Control •Hormones
7.Defense •Antibodies

Long chains of amino acids
structure of an Amino Acid
Five components of amino acid structure

Protein function is based on shape
•Shape is based on sequence of amino acids

loss of shape and function due to heat or pH

1.Primary structure 2.Secondary structure 3.Tertiary structure 4.Quaternary structure

The sequence of amino acids along a
polypeptide

Hydrogen bonds form spirals or pleats

Secondary structure folds into a unique shape

Final protein shape — several tertiary
structures together

-Catalysts
-Proteins that lower the activation energy of a chemical reaction
-Not changed or used up in the reaction

1.Specificity—will only work on limited types of
substrates
2.Saturation Limits—by their concentration
3.Regulation—by other cellular chemicals

Cofactor, Coenzyme, Isozymes

An ion or molecule that binds to an enzyme before
substrates can bind

Nonprotein organic cofactors (vitamins)

Two enzymes that can catalyze the same reaction

Large protein + small carbohydrate Includes enzymes, antibodies, hormones, and mucus
production

Large polysaccharides + polypeptides Promote viscosity

Nucleic Acids (C, H, O, N, and P) Are large organic molecules, found in the nucleus, which
store and process information at the molecular
level

Determines inherited characteristics Directs protein synthesis Controls enzyme production
Controls metabolism

Controls intermediate steps in protein synthesis

Enzyme that catalyzes the covalent bond between the phosphate of one nucleotide and the deoxyribose (sugar) of the next nucleotide

3’ end has a free deoxyribose
5’ end has a free phosphate
DNA polymerase:
•can only build the new strand in the 5’ to 3’ direction
•Thus scans the template strand in 3’ to 5’ direction

-Messenger RNA (mRNA)
-Transfer RNA (tRNA)
-Ribosomal RNA (rRNA)

Adenosine diphosphate (ADP)
Two phosphate groups; di-= 2
Adenosine triphosphate (ATP)
Three phosphate groups; tri-= 3

Adding a phosphate group to ADP with a high
-energy bond to form the high
-energy compound ATP

The enzyme that catalyzes the conversion of ATP to
ADP

-Assembled using Nucleotides
-Bonds are broken by cells to release energy as
needed
-During digestion and cellular respiration:
-energy from food is transferred to high energy
compounds for quick and easy access.