Synthesis Reactions - Anabolism

A + B 6 AB

Reactants Product

 

Decomposition Reactions - Catabolism.

AB 6 A + B

Exchange Reactions.

Exchange reactions involve the replacement of one atom or atoms by another atom or atoms.

AB + CD 6 AD + BC

 

Reversible Reactions.

In reversible reactions, end products can revert to the original combining molecules.

AB º A + B

 

CO2 + H2O º H2CO3 º H+ + HCO3-

Inorganic acids, bases, and salts dissociate into ions in water.

An acid ionizes into one or more hydrogen ions (H+) and one or more anions. Since H+ is nothing more than a proton, an acid may also be defined as a proton donor.

A base ionizes into one or more hydroxide ions (OH-) and one or more cations. A base can also be viewed as a proton acceptor.

A salt ionizes into anions and cations, neither H+ nor OH- ions.

Concentration = 0.00001 grams / liter

1 X 10-5 = pH 5

Concentration = 0.001 grams / liter

1X10-3 = pH 3

Maintaining pH: Buffer Systems.- second semester

CO2 + H2O º H2CO3 º H+ + HCO3-

                            Carbonic acid                 Bicarbonate ion(base)

Water:

is an excellent solvent, which means that many substances can be dissolved in water.

The substance which is dissolved in a solvent is called the solute.

The combination of solvent and solute is called a solution.

Water also participates in chemical reactions :

dehydration synthesis reactions:

AH + BOH 6 AB + H20

hydrolysis:

AB + H20 6 AH + BOH

Organic Molecules

Macromolecules are made by joining smaller subunits called monomers.

Carbohydrates: Cx (H20) y C12H22011

Monosaccharides - single sugars

Disaccharides - double sugars

Polysaccharides - complex carbohydrates - long chains of simple sugars

Lipids: C, H, O

Glycerol - 3 carbon "backbone"

Fatty acids - carbon chains with a carboxyl group at one end

Phospholipids - glycerol, 2 fatty acids and a phosphate group

Steroids based on Cholesterol - complex ring structure

Proteins: C, H, O, N (S)

Amino acids:

amino group : -NH2

Carboxyl (acid) group: - COOH

Side chain or R group

Peptide bonds

A protein’s structure determines its function.

Primary structure: the order of amino acids

Secondary structure: repeated twisting or folding into a helix or pleated sheet

Tertiary structure: the three-dimensional structure of the protein

(Quaternary structure: how polypeptides fit together to form the protein)

Enzymes: catalysts

Apopenzyme - protein portion

Cofactor (coenzyme)

Apoenzyme + cofactor = holoenzyme

Specific

Efficient

Controlled

Names end in -ase : Oxidase, dehydrogenase, protease

 

Nucleic Acids: C, H, O, N, P

Deoxyribonucleic acid - DNA

Ribonucleic acid - RNA

Nucleotides (monomers) made of:

Nitrogenous base:

Adenine, Thymine, Cytosine and Guanine in DNA

In RNA uracil substitutes for thymine.

A pentose sugar: deoxyribose in DNA and ribose in RNA.

A phosphate group

Double Helix

A pairs with T (or U)

C pairs with G

Adenosine Triphosphate - ATP Energy currency of the cell

Adenine

Ribose

Three phosphate groups