A gene is a unit of heredity that contains the instructions for making proteins, which control the structure and function of the body. Genes are segments of DNA (deoxyribonucleic acid) and are passed from parents to offspring, determining inherited traits such as eye color, height, and susceptibility to diseases.
Each gene acts like a biological instruction manual, guiding cells on how and when to produce specific proteins that influence growth, development, and bodily functions.
Structure of a Gene
- Genes are made up of DNA, which consists of four nucleotide bases:
Adenine (A), Thymine (T), Cytosine (C), and Guanine (G). - These bases form specific pairs (A-T and C-G) in a double-helix structure.
- Genes are located on chromosomes inside the nucleus of a cell.
- Humans have approximately 20,000-25,000 genes, spread across 23 pairs of chromosomes.
Functions of Genes
- Protein Synthesis
- Genes provide instructions for making proteins, which are essential for cell function.
- This process occurs in two steps:
- Transcription (DNA → RNA)
- Translation (RNA → Protein)
- Determining Traits
- Genes influence physical and biological traits (e.g., eye color, blood type, metabolism).
- Cell Regulation & Growth
- Certain genes control cell division and repair, preventing diseases like cancer.
- Inheritance of Genetic Information
- Genes are passed from parents to children, shaping genetic identity.
Types of Genes
- Structural Genes – Code for proteins that form body structures (e.g., muscle, skin).
- Regulatory Genes – Control gene expression, turning other genes on or off.
- Housekeeping Genes – Essential for basic cellular functions (e.g., energy production).
- Mutated Genes – Changes (mutations) in genes can cause genetic disorders or evolution.
Alleles & Gene Variability
- Alleles are different versions of a gene that determine trait variations.
- Example: The gene for eye color has alleles for brown, blue, or green eyes.
- Some alleles are dominant (expressed more often), while others are recessive.
Genes & Health
✅ Healthy Genes – Regulate normal growth, immune function, metabolism.
🚨 Mutated Genes – Can lead to genetic disorders like cystic fibrosis, sickle cell anemia, or cancer.
Conclusion
Genes are the blueprints of life, controlling traits, body functions, and health. Understanding genes helps us explore genetics, disease prevention, ancestry, and biotechnology.