Fig Experiment 1 Experiment 2 EXPERIMENT RESULTS SG1G1 M G1G1 M M S S When a cell in the S phase was fused with a cell in G 1, the G 1 nucleus immediately entered the S phase—DNA was synthesized. When a cell in the M phase was fused with a cell in G 1, the G 1 nucleus immediately began mitosis—a spindle formed and chromatin condensed, even though the chromosome had not been duplicated.
Fig Protein kinase activity (– ) % of dividing cells (– ) Time (min) RESULTS
Fig M G1G1 S G2G2 M G1G1 SG2G2 M G1G1 MPF activity Cyclin concentration Time (a) Fluctuation of MPF activity and cyclin concentration during the cell cycle Degraded cyclin Cdk G1G1 S G2G2 M G2G2 checkpoint Cyclin is degraded Cyclin MPF (b) Molecular mechanisms that help regulate the cell cycle Cyclin accumulation
Fig a Time (a) Fluctuation of MPF activity and cyclin concentration during the cell cycle Cyclin concentration MPF activity M M M SS G1G1 G1G1 G1G1 G2G2 G2G2
Fig b Cyclin is degraded Cdk MPF Cdk M S G1G1 G 2 checkpoint Degraded cyclin Cyclin (b) Molecular mechanisms that help regulate the cell cycle G2G2 Cyclin accumulation
Fig Tumor A tumor grows from a single cancer cell. Glandular tissue Lymph vessel Blood vessel Metastatic tumor Cancer cell Cancer cells invade neigh- boring tissue. Cancer cells spread to other parts of the body. Cancer cells may survive and establish a new tumor in another part of the body
Fig. 12-UN1 Telophase and Cytokinesis Anaphase Metaphase Prometaphase Prophase MITOTIC (M) PHASE Cytokinesis Mitosis S G1G1 G2G2