BIOMOLECULES
“Carbon is Central to the Living World”
Carbon is a central element to life because most biological molecules are built on
a carbon framework.
The complexity of living things is facilitated by carbon’s linkage capacity.
Carbon has great bonding capacity due to its structure.
Carbon’s outer shell has only four of the eight electrons necessary for maximum
stability in most elements.
Carbon atoms are thus able to form stable, covalent bonds with a wide variety of
atoms, including other carbon atoms.
Functional Groups
Groups of atoms known as functional groups can confer special properties on
carbon-based molecules.
CARBOHYDRATES
are organic compounds consisting of carbon, hydrogen and oxygen, where the
proportion of hydrogen atoms is to one Cm(H2O)n.
are the chief energy sources in all organisms.
Made up of carbon, hydrogen and oxygen atoms
Carbohydrates can be classified as:
Monosaccharides- simple sugars which consist of only one sugar unit (C6H12O6)
1.1 Glucose- the most common monosaccharide, is also known as dextrose or
blood sugar.It easily dissolves in water.
Galactose- a part of lactose (a disaccharide commonly called as milk sugar)
1.3 Fructose- the “corn sugar” is the sweetest sugar. It is ten times sweeter
than lactose. It is found in fruits such as atis, melon and ripe mangoes.
Disaccharides- double sugars which consist of two sugar units (C12H22O11)
2.1 Sucrose- formed from the chemical combination of glucose and fructose.
It is the common table sugar used to sweeten our drinks and foods
Lactose- a milk sugar. It is formed in the combination of glucose and galactose.
Maltose- malt sugar. It is the raw material used to make beer.
Polysaccharides- complex form of carbohydrates that consist of three or more
sugar units
Starch is the nutrient storage form of carbohydrates in plants.
Glycogen is the nutrient storage form of carbohydrates in animals.
Cellulose is a rigid, structural carbohydrate found in the cells walls of many
organisms.
Chitin is a tough carbohydrate that forms the external skeleton of arthropods.
Proteins
are an extremely diverse group of biological molecules composed of the
monomers called amino acids that are linked by a strong peptide bond.
They are made up of carbon, hydrogen, oxygen and nitrogen atoms. Sulfur,
phosphorus and iron may also be present
Sequences of amino acids are strung together to produce polypeptide chains,
which then fold up into working proteins.
Important groups of proteins include enzymes, which hasten chemical reactions,
and structural proteins, which make up such structures as hair.
Amino Acid
as the building block of protein, it is consist of functional groups such as amino
group and carboxyl group, carbon, hydrogen and Radical or side chain (identifies
the kind of amino acid ex. gly(glycine), ala (alanine) leu (leucine)
Nucleic acids
are polymers composed of nucleotides.
Two types of nucleic acids
Deoxyribonucleic Acid (DNA) - is a repository of genetic information in a
double helix structure (James D. Watson and Francis Crick)
DNA nucleotide is composed of sugar (deoxyribose), a phosphate group and
nitrogenous base
Ribonucleic Acid (RNA) - transports the information encoded in DNA to the
sites of protein synthesis, structures
called ribosomes and which helps make up the structure of ribosomes.
made up of nucleotide arranged in a single strand
RNA nucleotide is composed of sugar (ribose), a phosphate group and
nitrogenous base
Nitrogenous Bases DNA RNA
Cytosine (C) Guanine (G)
Adenine (A) Thymine (T) Uracil (U)
Guanine (G) Cytosine (C)
Thymine (T) Adenine (A)
Example AGGCTAACCT – TCCGATTGGA (DNA)
ACCGAUGGAU - UGGCUACCUA
Lipids
The defining characteristic of all lipids is that they do not readily dissolve in
water.
They do not possess the monomers-to-polymers structure seen in other biological
molecules; no one structural element is common to all lipids.
A third class of lipids is the phospholipids, each of which is composed of two
fatty acids, glycerol, and a phosphate group.
The material forming the outer membrane of cells is largely composed of
phospholipids
Lipids occur in many forms: fatty acids, phosphoglycerides, sphingolipids, waxes
and steroids.
