Mutations and Cell Cycle
Mutations are changes in the coding sequence of a gene that can either help organisms adapt or make survival more difficult. Point mutations include silent mutations (no effect on the protein), missense mutations (changed protein), and nonsense mutations (premature stop in protein production). Frameshift mutations occur through insertions (adding bases) or deletions (removing bases), which shift how the genetic code is read.
The cell cycle begins with interphase, which includes G1 (organelle replication), S (DNA replication), and G2 (final checks). DNA exists as loose chromatin when not dividing, but condenses into chromatids during division. After replication, the chromosome consists of two sister chromatids joined at the centromere, where kinetochore proteins later connect to spindle fibers.
Mitosis has four main phases Prophase (nuclear membrane dissolves, DNA condenses), Metaphase (chromosomes align in middle), Anaphase (sister chromatids separate), and Telophase (nuclear membrane reforms). The process concludes with cytokinesis, where the cell physically divides into two identical daughter cells.
Fascinating fact! Your body replaces millions of cells every day through mitosis - that's why you can heal cuts and grow new skin cells without even thinking about it!