El CICLO CELULAR (Paso a Paso)
Cycling Through Cell Division
The cell cycle in eukaryotic cells involves three main phases: interphase, mitosis, and cytokinesis. This process aims to produce two daughter cells with identical chromosomes.
Interphase and Preparation for Division
- The cell cycle involves producing two daughter cells with identical chromosomes.
- Interphase consists of three stages: G1, S, and G2. During G1, the cell grows and duplicates organelles.
- The most critical checkpoint in the cell cycle is the restriction point in G1 where the cell evaluates its replicative potential.
- Cells that exit the cycle enter a phase called G0, where they remain metabolically active but do not progress through the cycle.
DNA Replication and Chromosome Duplication
- DNA replication occurs during the synthesis (S) phase of interphase.
- Chromosomes duplicate at multiple sites along the chromosomal DNA during S phase.
- Duplicated chromosomes condense in preparation for mitosis, allowing for genetic material separation.
Mitosis and Cell Division
- Mitosis involves growth and reorganization before entering the mitotic phase.
- Mitosis includes karyokinesis (nuclear division) and cytokinesis (cell division), lasting about an hour.
- In humans, approximately 25 million cell divisions occur per second in adults.
Cell Cycle Duration and Regulation
- The duration of the cell cycle varies among different cell types due to factors like metabolism and division speed.
- Cellular activities continue throughout the cell cycle, consuming energy for processes like division.
- Internal quality control mechanisms regulate cell progression through checkpoints based on cellular signals.
Regulation of Cell Cycle
Internal control mechanisms modulate transitions between cell cycle stages based on intracellular or environmental signals.
Control Mechanisms in Cell Cycle
- Checkpoints ensure specific conditions are met before cells progress through the cycle.