Organic

Chemistry

and the

Genetic

Code

Organic chemistry: Compounds in which

Carbon is the principal element.

Recall carbon as the leading Group IV element in

the Periodic Table, with 4 valence electrons.

The study of compounds that do not contain

carbon as a central element is called:

Inorganic Chemistry.

The majority of known compounds are organic.

Several million are known .

Thousands more are created each year.

Fossil fuels, oil & gasoline, all food & beverages, plant & animal substances, synthetic and natural rubbers, polymers, plastics, and pharmaceuticals.

Hydrocarbons

Alkanes

Single C-C Bonds

Alkenes

Double C=C Bonds

Alkynes

Triple C=C Bonds

Ethylene ( Ethene )

Acetylene ( Ethyne )

Organic compounds may contain other elements or groups

besides C and H.

Oxygen, nitrogen, the halogens

( fluorine, chlorine, bromine, iodine )

phosphorus or sulfur.

NO2 (nitrate) group

OH (hydroxide) group

PO4 (phosphate) group

Molecular structures: Dashes between atoms represent chemical bonds.

1 bond = 2 electrons

Octet rule: Carbon atom has 4 dashes

around it ( 2 x 4 = 8 electrons ).

Double or triple bonds:

Less hydrogen H atoms attached

Unsaturated

Simple molecules can combine with each other to form long chains of molecules with identical repeating units or groups.

Polymers (“many units”).

Individual segments monomers.

E.G. Ethylene is heated under pressure with a catalyst to form polyethylene, the most popular industrial plastic in the world.

E.G.

Plastic bags, shampoo & beverage bottles, toys, CD covers, bullet-proof vests.

.

1 hydroxide OH group per molecule is called an alcohol. E.G. Methanol, ethanol, and isopropyl alcohol all have 1 OH group attached to them.

2 hydroxyl OH groups per molecule is called a glycol. E.G. Ethylene glycol is the major component of antifreeze.

3 hydroxyl OH groups per molecule is called a glycerol. Glycerol is a building block of fat molecules and a by-product in the manufacture of soap. Used in toothpastes, lotions, and candy to retain moisture / softness.

Carbohydrates are carbon, hydrogen and

oxygen ( C-H-O ) compounds.

Simple sugars ( or monosaccharides )

provide fuel for living cells.

Glucose (C6H12O6)

Provides energy and shape to certain cells.

Essential role in molecular genetics.

Polypeptides: Enzymes & catalysts. Increase the

rate of chemical reactions in living things.

Hemoglobin: Serves as an oxygen carrier.

Collagen: Provides shape and support.

Responsible for muscle movement.

Hormones: Chemical messengers secreted by

endocrine glands to regulate the body.

Antibodies: Globular proteins made up by the

body in response to the presence of a foreign

or harmful molecule called an antigen.

Proteins are polymers made up of

monomers known as amino acids:

Amino group ( NH2 )

Carboxylic Acid group ( COOH )

Segment of DNA that is able to:

Replicate itself

Mutate (or change) itself

Store information about itself

Synthesize new structural proteins essential to the operation of the cell or organism.

Physical Traits

~ Functions ~

Replication: Ability to reproduce itself.

Transcription: Ability to supervise the

manufacture of RNA.

Translation: Production of new protein

molecules by RNA.

~~~~~~~~~~~~~~~~~~~~~~~~ DNA is the

genetic material determining which proteins

will be manufactured.

Nucleic acids (DNA / RNA) composed of

fundamental monomers

Nucleotide monomer is composed of:

1) Sugar molecule ( 5-member

carbon ring skeleton ) 2) Phosphate

( PO4 group ) 3) Base or Amino

acid ( Hexagonal 6-

member C-N ring skeleton)

Adenine: A

Guanine: G

Cytosine: C

Uracil: U Thymine:

T~~~~~~

~~~~~~~~~~~DNA has

bases A, T, G, C RNA has

bases A, U, G, C

DNA is actually a double molecule.

Composed of two strands to form a

ladder- like structure (double helix)

thousands of nucleotide bases long.

Strands are attached between their bases

according to the base pair rule:

A – T G – C

The 4 letters in the nucleic acid “alphabet”

yield 64 possible unique 3-letter words.

This is the basis of the genetic code

for all living organisms.

If these bases are read in groups of three,

they make sense to us ( CAT, TAG, ACT ).

To make sense out of such a code,

it is necessary to read in only one direction

(as in many languages).

DNA replication is stunningly accurate.

1 error made for every 2 billion nucleotides.

Human cell: 46

chromosomes ~ 3 billion

base pairs ~ 1.5 errors

per cell Because this rate of

error is so small, DNA replication is

considered to be

“Error – free”