DNA or deoxyribonucleic acid is a molecule which carry genetic instruction used in the functioning ,development ,reproduction and growth of all living organism including viruses. DNA are composed of simpler monomer units called nucleotide. They are termed polynucleotide as DNA have two strands. Nucleotides is composed of four nitrogenous base, they are ADENINE(A), THYMINE (T),CYTOSINE(C), and GUANINE (G).””(DNA) DNA bases pair up with each other, A:T and C:G, to form units called base pairs. Each base is also attached to a sugar molecule and a phosphate molecule. Together, a base, sugar, and phosphate are called a nucleotide. Nucleotides are arranged in two long strands that form a spiral called a double helix. The …show more content…
Genes which are made up of DNA, act as instructions to make molecules called proteins. Small changes in the sequence of base pairing in our genes make each person unique.
In our daily life, we can see human, birds and animals, insects and many other living organism of same species with different structures. Everyone has a very significant unique body structure which we can differentiate from their limbs and other body parts by shape and physical feature. This is due to the action of homeotic genes during growth of embryo which develop the unique body structure. Infact, each gene carries a set of instruction for building a specific protein.those complete set of gene is known as genome which is a set of instructions that build the entire organism.
“Scientist discover genes that determine body pattern by studying the transformation in insect such as fruit flies. ED lewis at caltech discover that the modification which is known as homeric transformation ure caused by defect in single gere. The embryo has its basic body plan, it adds the details .Limbs and organs grown between the particular weeks of development. To form a new body parts, an area in the embryo is first marked out.genes controls and instruct the cells in area what to do. For example, become a part of an arm; cell pass on these messages to their neighbour cell.”(genetic