- Always contain Carbon
- Usually contain Hydrogen
-Always have covalent bonds.
- Many are made up of long chain of Carbon atoms
-Make up 38- 43 % of the human body.
- Have unique characteristics that allow them to carry out complex functions.
IMPORTANT CATEGORIES
1. CARBOHYDRATES
2. LIPIDS
3. PROTEINS
4. NUCLEIC ACIDS
5. ATP
CARBON AND FUNCTIONAL GROUPS
Carbon can form bond with 1 to 1000 carbon atoms to produce large molecules that can have different shapes
CARBON SKELETON
The chain of carbon atoms in an organic molecule.
HYDROCARBONS
Carbons bonded to Hydrogen atoms.
FUNCTIONAL GROUP
An atom or group of atoms
- that replaces hydrogen in an organic compound
- that defines the structure of a family of compounds
- determines the properties of the family.
Each type of functional group has a specific arrangement of atoms that confers characteristic chemical properties on the organic molecules attached to it.
MAJOR FUNCTIONAL GROUPS
R = VARIABLE GROUP.
1. Hydroxyl R - O - H
2. Sulfhydryl R - S -H
3. Carbonyl R - C=O.
4. Carboxyl R - COOH
5. Ester R - COO
6. Phosphate R - PO4 2–
7. Amino R - NH2
1. Hydroxyl -OH
R - O -H
- Alcohols
- Contain an -OH group
-Is polar
and
hydrophilic due to its electronegative Oxygen atom.
- Molecules with many -OH groups
- dissolve easily in water
eg. Ethanol - C2H5OH
2. Sulfhydryl -SH
R - S - H
THIOLS or MERCAPTANS
-Have an -SH group
-Is polar and hydrophilic
- due to its electronegative Sulphur atom.
eg.Methyl mercaptan CH3-SH
Certain amino acids contain -SH groups
-which stabilize the shape of proteins
eg . Cysteine
3. Carbonyl R - C=O.
KETONES R - CO - R
A. KETONES R - CO - R
-Contains a carbonyl group with in the carbon skeleton.
The carbonyl group is polar and hydrophilic
- due to its electronegative Oxygen atom.
eg. Acetone.
B. ALDEHYDE -CHO
-Have a carbonyl group at the end of the carbon skeleton.
eg. acetaldehyde
4. Carboxyl - COOH
CARBOXYLIC ACID -COOH
Carboxylic acids contain a carboxyl group at the end of the carbon skeleton.
All amino acids have a -COOH group at 1 end.
The negatively charged form predominates at the pH of body cells
- is hydrophilic.
eg. Acetic acid CH3COOH
5. ESTER -COO
-Predominate in dietary fats and oils
- Occur in our body in trigycerides
eg. Aspirin
-is an ester of Salicylic acid
- a pain relieving molecule
- found in the bark of the willow tree.
6. PHOSPHATE -PO4 2-
- Contain a phosphate group
- Is very hydrophilic due to dual negative charges
eg. ATP
7. Amino -NH2
-Amines have an -NH2 group.
- Can act as a base.
- Pick up a Hydrogen ion
- giving the amino group a positive charge .
At the pH of body fluids,
most amino groups have a charge of 1+.
All amino acids have an amino group at 1 end.
MACROMOLECULES
macro= large
- Small organic molecules can combine into very large molecules.
- Are usually polymers
eg. Carbohydrates
A. MONOMERS
B. POLYMERS
MONOMERS
mono= 1
- mers = parts
- small building block molecules.
POLYMERS
poly= many
A polymer is a large molecule formed by the covalent bonding of many identical or similar monomers.
The reaction that joins 2 monomers is normally a dehydration synthesis.
DEHYDRATION SYNTHESIS REACTION
In this type of reaction,
- a hydrogen atom is removed from 1 monomer
- a hydroxylgroup is removed from other
- to form a molecule of water.
ISOMERS
iso= equal
Molecules that have same molecular formula
but different structure
eg.
Molecular formula for glucose and fructose are both C6H12O6
But structural formula differs giving different chemical properties
- because relative positions of oxygen and carbon atoms are different.
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