What is the structure and function of DNA?

 🧬 What Is the Structure and Function of DNA?

DNA (Deoxyribonucleic Acid) is the molecule of life. It carries the genetic instructions used in the growth, development, functioning, and reproduction of all living organisms and many viruses.

🧱 1. Structure of DNA

• DNA has a double helix structure—imagine a twisted ladder.

🧬 The DNA Molecule:

• Backbone: Made of sugar (deoxyribose) and phosphate groups
• Rungs: Made of nitrogenous bases paired in specific ways

🔗 Base Pairing Rules (Complementary Bases):

• Adenine (A) pairs with Thymine (T)
• Cytosine (C) pairs with Guanine (G)
• (A↔T and C↔G)
• Each "step" of the ladder is a base pair, and the sequence of these bases makes up the genetic code.

📦 DNA Organization:

• DNA is tightly coiled into chromosomes inside the nucleus of cells.
• A gene is a segment of DNA that codes for a specific protein.

⚙️ 2. Function of DNA

✅ A. Stores Genetic Information

• DNA holds the instructions for making proteins, which do most of the work in cells.

✅ B. Guides Protein Synthesis

Through two key steps:

• Transcription (in the nucleus):
• DNA is copied into mRNA (messenger RNA)
• Translation (in the ribosome):
• mRNA is read to assemble amino acids into a protein

🧩 The order of bases (A, T, C, G) determines the order of amino acids in a protein.

✅ C. Passes Traits to Offspring

• During reproduction, DNA is passed from parents to offspring.
• This is the basis of heredity.

🧪 Why DNA Matters:

• Role Description
• Blueprint of life Contains instructions for all living processes
• Controls traits Determines everything from eye color to enzyme production
• Basis of inheritance Passed down through generations
• Used in technology DNA profiling, genetic engineering, CRISPR, forensics, etc.

📊 Summary Table

• Feature DNA
• Shape Double helix
• Components Sugar, phosphate, nitrogen bases
• Base Pairs A–T, C–G
• Found In Nucleus (in eukaryotes)
• Function Stores genetic info, directs protein synthesis, passes traits