1. 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.

2. 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.

3. 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

4. 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.

5. 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.

6. 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.

7. 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.

8. Chapter 4
Section 3 The Cell Cycle

9. 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.

10. 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

11. 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.

12. Section 3 The Cell Cycle
Chapter 4

13. Section 3 The Cell Cycle
Chapter 4

14. 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.