Inheritance and DNA Cellular Basis of Reproduction & Inheritance Chapter 8 The cell cycle multiplies cells and consists of two major phases Figure 8.5 The stages of cell division Figure 8.6 (Part 1) Figure 8.6 (Part 2) Cytokinesis differs for plant and animal cells Figure 8.7A The binding of growth factors to specific receptors on the plasma membrane is usually necessary for cell division. Control system G1 S G2 M G1 checkpoint Plasma membrane Growth factor Receptor protein Relay proteins Signal transduction pathway Figure 8.9B Cancer cells divide excessively to form masses of cells called tumors Malignant tumors can invade other tissues Tumor Glandular tissue A tumor grows from a single cancer cell. Cancer cells invade neighboring tissue.