Ch. 2 - The Chemistry of Biology

all materials that occupy space and have mass

atoms

simplest form of matter not divisible into simpler substances

(+) subatomic particles

neutral subatomic particles

(-) subatomic particles

1. Gravity

2. Electromagnetism

3. Strong nuclear force

4. Weak Force

like charges repel, unlike attract

Holds nucleus together

Radioactivity (neutron)

The same fundamental structure

pure substances w/ a characteristic number of protons, neutrons, and electrons and predictable chemical behaviors

number of protons

number of protons and neutrons

variant forms of the same element that differ in the number of neutrons

average mass numbers of all isotopic forms

volumes of space surrounding the atomic nucleus where electrons are likely to be found

a chemical substance that results from the combination of two or more atoms

molecules that are combinations of two or more different elements

sum of all of the atomic masses of the atoms a molecule contains

when 2 or more atoms share, donate, or accept electrons to form molecules and compounds

1. Covalent bonds

2. Ionic bonds

3. Hydrogen bonds

• electrons are shared among atoms

• strongest

• unequal sharing (negative and positive pole)

equal sharing

• one or more electrons from one atom are removed and attached to another atom which forms positively charge cations and negatively charged anions

• least important

weak bonds between hydrogen and other atoms

• electrons are not shared, lost, or gained

compounds containing carbon bonded to hydrogens

aqueous dissociation of an electrolyte into ions

a particular molecular combination that reacts in predictable ways and confers particular properties on a compound

The chemical class of certain groups of organic compounds

• Carbon

• Hydrogen

• Oxygen

• Phosphate

• Potassium

• Iodine

• Nitrogen

• Sulfer

• Calcium

• Iron

• Magnesium

• Sodium

• Chlorine

• accessory molecules that bind to organic compounds

• confer unique reactive properties on the whole molecule

R-OH

Alcohols and carbohydrates

R−COOH

Fatty acids, proteins, organic acids

R-CH(NH2)-COOH

Proteins, nucleic acids

R-COO-R

Lipids

DNA, RNA, ATP

A compound containing primarily carbon, hydrogen, and oxygen in a 1:2:1 ratio

(CH2O)n

loss of water in a polymerization reaction

polysaccharides provide cell structure, adhesion and metabolism

Cellulose provides the strength and rigidity of the cell wall

• Polysaccharide similar to cellulose in chemical structure

• Major compound in the cell walls of fungi and the exoskeletons of insects

• When polysaccharides are linked to peptide fragments

• Provides the main source of structural support to the bacterial cell wall

Lipopolysaccharide

LPS of gram-negative bacteria is an endotoxin w/ generalized pathologic effects such as fever

• attachment to other cells

• site for receptors

• carbohydrate-rich molecule

link of subunits of disaccharides and polysaccharides

Molecule composed of short chains of amino acids, such as a dipeptide, tripeptide, and a tetrapeptide

Forms when two hydroxyl groups in phosphoric acid react w/ a hydroxyl group on other molecules, forming ester bonds

Occurs between sulfur atoms on the amino acid cysteine

• long hydrophobic, C-H chains attached to a glycerol molecule

• created by dehydration synthesis

• triglycerides, phospholipids, steroids and waxes

• 3 fatty acids bound to glycerol

• Saturated/unsaturated

• Energy storage

has all carbons in the chain bonded to hydrogen w/ single bonds

Has at least one carbon-carbon double bond

Solid fats (butter)

Oils (liquid fats)

• Raise your cholesterol levels

• Increase risk of heart disease

• low density lipoproteins

• Lower cholesterol levels

• Glycerol w/ 2 fatty acids + a phosphate group

• Bilayers of phospholipids form membranes

Impenetrable barrier that accounts for the selective permeability and transport of molecules

Through peptide bonds

support, enzymes, defense, transport, movement

• Series of amino acids bound in a chain

• Amino acids display small charged functional groups

• Develops when CO- and NH- groups on adjacent amino acids form hydrogen bonds

  • then folds the chain forming an alpha helix and beta pleated sheet

• forms when parts of the secondary structure interact by forming covalent disulfide bonds and other interactions

• creates a 3-D mass

• exists only in proteins that consist of more than 1 polypeptide chain

• typical of antibodies and some enzymes that act in cell synthesis

• adenine & thymine, cytosine & guanine

• Double Helix

• formed by 2 very long polynucleotide strands linked along their length by hydrogen bonds between the nitrogenous bases

• polynucleotide that consists of a long chain of nucleotides

• single strand that contains ribose sugar instead of deoxyribose

• uracil instead of thymine

mRNA: messenger RNA

tRNA: transfer RNA

rRNA: ribosomal RNA

• two rings

• 2 types: adenine & guanine

• one ring

• 3 types: thymine, cytosine, and uracil

• adenosine triphosphate

  • nucleotide: adenine, ribose, 3 phosphates

transfer and storage of energy