Molecular Biology is the branch of science that focuses on understanding the structure and function of the molecules that make up cells, particularly DNA, RNA, and proteins. It explores how genetic information is stored, transferred, and expressed in living organisms—essentially, how genes work at the molecular level. Key Concepts in Molecular Biology: DNA (Deoxyribonucleic Acid): The molecule that carries genetic instructions. Molecular biology studies how DNA is replicated and passed on to new cells. RNA (Ribonucleic Acid): A messenger between DNA and proteins. Includes various types (mRNA, tRNA, rRNA) involved in gene expression. Proteins: Molecules that do most of the work in cells—enzymes, hormones, structural components. Molecular biology examines how genes are used to build proteins through transcription and translation. Gene Expression & Regulation: How certain genes are turned "on" or "off" depending on the cell's needs. Mutations: Changes in DNA that can lead to diseases like cancer or genetic disorders. Techniques in Molecular Biology: PCR (Polymerase Chain Reaction): Amplifies DNA. Gel Electrophoresis: Separates DNA fragments. Cloning and Gene Editing (e.g. CRISPR): Modify genes. Sequencing: Determines the exact order of DNA bases. Why Is Molecular Biology Important? It’s critical for understanding how cells function and how diseases develop. It underpins genetics, biotechnology, cancer research, and drug development. It’s used in diagnostic labs to detect genetic disorders, infections, and cancers. In summary, molecular biology is the science of life at the molecular level—it explains how genes and proteins control the structure and function of every living thing.