Chapter 4 Section 3 The Cell Cycle Bellringer “Biology is the only science in which multiplication means the same thing as division—at least with regards to cells.” Explain what is meant by this statement in your science journal.

Chapter 4 Objectives Explain how cells produce more cells. Section 3 The Cell Cycle Objectives Explain how cells produce more cells. Describe the process of mitosis. Explain how cell division differs in animals and plants.

Chapter 4 Vocabulary cell cycle chromosome binary fission Section 3 The Cell Cycle Vocabulary cell cycle chromosome binary fission homologous chromosomes chromatid centromere mitosis cytokinesis

Chapter 4 The Life of a Cell Section 3 The Cell Cycle The Life of a Cell The cell cycle begins when the cell is formed and ends when the cell divides and forms new cells.

Chapter 4 The Life of a Cell Section 3 The Cell Cycle The Life of a Cell Before a cell divides, it must make a copy of its DNA which is organized into structures called chromosomes.

Chapter 4 The Life of a Cell Section 3 The Cell Cycle The Life of a Cell Making More Prokaryotic Cells Cell division in bacteria is called binary fission, which means “splitting into two parts.” Bacteria have a single circular DNA molecule (chromosome). Binary fission results in two cells that each contain one copy of the circle of DNA.

Chapter 4 The Life of a Cell Section 3 The Cell Cycle The Life of a Cell The chromosomes of eukaryotic cells contain more DNA than those of prokaryotic cells. In a eukaryotic cell, chromosomes are found in the nucleus and are made of DNA and protein. Pairs of similar chromosomes are called homologous chromosomes. Humans have 46 chromosomes arranged in 23 pairs. Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 4 Section 3 The Cell Cycle

The Life of a Cell, continued Chapter 4 Section 3 The Cell Cycle The Life of a Cell, continued Making More Eukaryotic Cells The cell cycle has three stages: Interphase: The cell grows and copies its chromosomes. The two copies are now called chromatids. Mitosis: The chromatids separate. The cell splits into two identical cells.

Mitosis and the Cell Cycle Chapter 4 Section 3 The Cell Cycle Mitosis and the Cell Cycle Mitosis has four phases: prophase metaphase anaphase telophase

Mitosis and the Cell Cycle Chapter 4 Section 3 The Cell Cycle Mitosis and the Cell Cycle Cytokinesis is the division of cytoplasm. In animal cells and other eukaryotes that do not have cell walls, division of the cytoplasm begins at the cell membrane. In plant cells and in other eukaryotes with cell walls, a cell plate forms and the cell splits into two cells.

Section 3 The Cell Cycle Chapter 4

Section 3 The Cell Cycle Chapter 4

Chapter 4 Section Summary Section 3 The Cell Cycle Section Summary A cell produces more cells by first copying its DNA. Eukaryotic cells produce more cells through the four phases of mitosis. Mitosis produces two cells that have the same number of chromosomes as the parent cell. At the end of mitosis, a cell divides the cytoplasm by cytokinesis. In plant cells, a cell plate forms between the two new cells during cytokinesis.