DNA Structure, Replication, and Biotechnology

DNA Structure and Function

DNA is a large molecule formed by the union of simpler molecules called nucleotides. The nucleotides correspond to the links of a long chain and consist of:

• A molecule of phosphoric acid
• A carbohydrate called deoxyribose
• A nitrogenous base (adenine (A), guanine (G), cytosine (C), or thymine (T))

The DNA sequence is the order of DNA nucleotides. Each DNA molecule is composed of two long chains of nucleotides coiled up in a double helix. The two strands are chemically complementary. This is because the nitrogenous bases are joined and locked inside the double helix, with specific pairings: (A = T), (T = A), (C = G), and (G = C).

DNA Replication

The DNA molecule is the only molecule in living beings that can make an exact copy of itself, i.e., replicate. The daughter cells inherit the same genetic makeup as the parent cell. Thus, genetic information passes from generation to generation.

Process: The double helix is released from histones and opens like a zipper. The DNA strands serve as templates for synthesizing their complementary strands. Specific enzymes, DNA polymerases, join nucleotides one by one. This will form a new strand that is complementary to the one that served as a mold and identical to the chain previously attached to it.

Mutations

Mutations are errors that occur in the process of DNA replication. Some have no impact, while others can cause degenerative diseases.

Transcription and Translation

• Transcription: The process of synthesizing mRNA from DNA. The DNA serves as a template, RNA binds, and then targets ribosomes.
• Translation: The deciphering of the message (using the genetic code) to synthesize a protein. This process requires mRNA, tRNA, amino acids (aa), and ribosomes.

Other Important Concepts

• Chromosomes: Organelles containing rod-shaped DNA.
• Enzymes: Proteins that catalyze chemical reactions.
• Gene: A piece of DNA containing specific information.
• Anticodon: The union of 3 nucleotides of an mRNA with 3 nucleotides of a tRNA.
• Bioelements: The chemical elements of living beings.

Modern Biotechnology

Modern biotechnology involves the deliberate manipulation of the genetic material (DNA) of organisms to make or modify a product, improve plants or animals, or develop microorganisms for specific uses.

Techniques

Techniques include recombinant DNA technology, genetic engineering techniques, cell cloning techniques, and the cultivation of cells and tissues.