C E L L C Y C L E MITOSIS
The Cell Cycle Cells undergo an orderly sequence of events as they grow and divide. The sequence in the following slides show a typical cell cycle of an animal cell. The end result are two “daughter cells.” Each will then begin the cell cycle again.
Length of the Human Liver Cell Cycle
Chromosomes and DNA Chromosome structures of DNA and proteins Gene a section on a chromosome that has genetic information for a trait DNA deoxyribonucleic acid-genetic material
Phase One INTERPHASE The period during the cell cycle of a cell’s growth and development. Most cells go through three stages: 1. Rapid growth and replication 2. Copying DNA 3. Preparation for cell division
During Interphase, the cell grows, makes a copy of its DNA, and prepares to divide into two cells.
Phase 2 MITOSIS BEGINS
Chromatin in the nucleus condenses to form chromosomes Chromatin in the nucleus condenses to form chromosomes. The pairs of centrioles move to opposite sides of the nucleus. Spindle fibers form a bridge between the ends of the cell. The nuclear envelope breaks down.
The chromosomes line up across the center of the cell The chromosomes line up across the center of the cell. Each chromosome attaches to a spindle fiber at its centromere.
The centromeres split. The two chromatids separate, and each chromatid becomes a new chromosome. The new chromosomes move to opposite ends of the cell. The cell stretches out as the opposite ends are pushed apart.
The chromosomes begin to stretch out and lose their rod-like appearance. A new nuclear envelope forms around each region of chromosomes.
Stage 3 CYTOKINESIS
The cell membrane pinches in around the middle of the cell The cell membrane pinches in around the middle of the cell. The cell splits in two. Each daughter cell ends up with an identical set of chromosomes and about half the organelles.
The Cell Cycle
Results of Cell Division Reproduction Unicellular reproduction Growth Multicellular organism Replacement Replaces worn out cells Repair Repairing damage to most cells