The organization and function of genetic material is fundamental to understanding cell biology and disease.
DNA is packaged into chromosomes through an intricate folding process called DNA packaging. The DNA structure consists of a double helix that wraps around histone proteins to form nucleosomes, which further condense into chromatin fibers. These fibers are ultimately organized into chromosomes during cell division. The relationship between DNA, genes and chromosomes is hierarchical - genes are segments of DNA that code for proteins, while chromosomes are large structures containing many genes and regulatory sequences.
Cell division occurs through carefully regulated phases known as the cell cycle. The 4 stages of the cell cycle include G1, S, G2 (interphase), and M phase (mitosis). During mitosis, cells undergo distinct stages: prophase, metaphase (where the chromosomes line up in the center of the cell), anaphase, and telophase. This process ensures accurate distribution of genetic material to daughter cells. Understanding the Types of cells and phases of mitosis is crucial because disruption of normal cell division can lead to cancer. The relationship between the cell cycle and cancer involves mutations in genes that regulate cell growth and division. Proto-oncogenes can become cancer-causing oncogenes through mutations, leading to uncontrolled cell division at the genetic level. Additionally, mutations in tumor suppressor genes, which normally prevent excessive cell growth, can remove crucial checkpoints in the cancer cell cycle phases. These genetic changes allow cells to bypass normal growth controls, resulting in tumor formation and cancer progression. How mutated tumor suppressor genes affect the cell cycle is a key area of cancer research, as understanding these mechanisms is essential for developing targeted therapies.
