1. Chapter 9 Cellular Reproduction
Section 1: Cellular Growth
Section 2: Mitosis and Cytokinesis
Section 3: Cell Cycle Regulation
10.1: Meiosis

2. Ratio of Surface Area to Volume
Chapter 9
Cellular Reproduction
9.1 Cellular Growth
Ratio of Surface Area to Volume

3. Chapter 9
Cellular Reproduction
9.1 Cellular Growth
As the cell grows, its volume increases much more rapidly than the surface area.
The cell might have difficulty supplying nutrients and expelling enough waste products.

4. Transport of Substances
Chapter 9
Cellular Reproduction
9.1 Cellular Growth
Transport of Substances
Substances move by diffusion or by motor proteins.
Diffusion over large distances is slow and inefficient.
Small cells maintain more efficient transport systems.

5. Cellular Communications
Chapter 9
Cellular Reproduction
9.1 Cellular Growth
Cellular Communications
The need for signaling proteins to move throughout the cell also limits cell size.
Cell size affects the ability of the cell to communicate instructions for cellular functions.

6. Cell division prevents the cell from becoming too large.
Chapter 9
Cellular Reproduction
9.1 Cellular Growth
The Cell Cycle
Cell division prevents the cell from becoming too large.
It also is the way the cell reproduces so that you grow and heal certain injuries.
Cells reproduce by a cycle of growing and dividing called the cell cycle.

7. Chapter 9
Cellular Reproduction
9.1 Cellular Growth
Interphase is the stage during which the cell grows, carries out cellular functions, and replicates.
Mitosis is the stage of the cell cycle during which the cell’s nucleus and nuclear material divide.
Cytokinesis is the method by which a cell’s cytoplasm divides, creating a new cell.

8. The Stages of Interphase
Chapter 9
Cellular Reproduction
9.1 Cellular Growth
The Stages of Interphase
The first stage of interphase, G1
The cell is growing, carrying out normal cell functions, and preparing to replicate DNA.

9. The Second Stage of Interphase, S
Chapter 9
Cellular Reproduction
9.1 Cellular Growth
The Second Stage of Interphase, S
The cell copies its DNA in preparation for cell division.

10. The Third Stage of Interphase, G2
Chapter 9
Cellular Reproduction
9.1 Cellular Growth
The Third Stage of Interphase, G2
The cell prepares for the division of its nucleus.

11. The cell’s chromatin tightens.
Chapter 9
Cellular Reproduction
9.2 Mitosis and Cytokinesis
The Stages of Mitosis
Prophase
The cell’s chromatin tightens.
Sister chromatids are attached at the centromere.
Spindle fibers form in the cytoplasm.

12. The nuclear envelope seems to disappear.
Chapter 9
Cellular Reproduction
9.2 Mitosis and Cytokinesis
The nuclear envelope seems to disappear.
Spindle fibers attach to the sister chromatids.

13. They line up in the middle of the cell.
Chapter 9
Cellular Reproduction
9.2 Mitosis and Cytokinesis
Metaphase
Sister chromatids are pulled along the spindle apparatus toward the center of the cell.
They line up in the middle of the cell.

14. The microtubules of the spindle apparatus begin to shorten.
Chapter 9
Cellular Reproduction
9.2 Mitosis and Cytokinesis
Anaphase
The microtubules of the spindle apparatus begin to shorten.
The sister chromatids separate.
The chromosomes move toward the poles of the cell.

15. The chromosomes arrive at the poles and begin to relax.
Chapter 9
Cellular Reproduction
9.2 Mitosis and Cytokinesis
Telophase
The chromosomes arrive at the poles and begin to relax.
Two new nuclear membranes begin to form and the nucleoli reappear.
The spindle apparatus disassembles.

16. In animal cells, microfilaments constrict, or pinch, the cytoplasm.
Chapter 9
Cellular Reproduction
9.2 Mitosis and Cytokinesis
Cytokinesis
In animal cells, microfilaments constrict, or pinch, the cytoplasm.
In plant cells, a new structure, called a cell plate, forms.

17. Chapter 9
Cellular Reproduction

18. 9.3 Cell Cycle Regulation Normal Cell Cycle
Chapter 9
Cellular Reproduction
9.3 Cell Cycle Regulation
Normal Cell Cycle
Different cyclin/CDK combinations signal other activities, including DNA replication, protein synthesis, and nuclear division throughout the cell cycle.

19. Quality Control Checkpoints
Chapter 9
Cellular Reproduction
9.3 Cell Cycle Regulation
Quality Control Checkpoints
The cell cycle has built-in checkpoints that monitor the cycle and can stop it if something goes wrong.
Spindle checkpoints also have been identified in mitosis.

20. Abnormal Cell Cycle: Cancer
Chapter 9
Cellular Reproduction
9.3 Cell Cycle Regulation
Abnormal Cell Cycle: Cancer
Cancer is the uncontrolled growth and division of cells.
Cancer cells can kill an organism by crowding out normal
cells, resulting in the loss of tissue function.

21. Chapter 9
Cellular Reproduction
9.3 Cell Cycle Regulation
Causes of Cancer
The changes that occur in the regulation of cell growth and division of cancer cells are due to mutations.
Various environmental factors can affect the occurrence of cancer cells.

22. Apoptosis Programmed cell death
Chapter 9
Cellular Reproduction
9.3 Cell Cycle Regulation
Apoptosis
Programmed cell death
Cells going through apoptosis actually shrink and shrivel in a controlled process.

23. Chapter 9
Cellular Reproduction
9.3 Cell Cycle Regulation
Stem Cells
Unspecialized cells that can develop into specialized cells when under the right conditions

24. Chapter 9
Cellular Reproduction
9.3 Cell Cycle Regulation
Embryonic Stem Cells
After fertilization, the resulting mass of cells divides repeatedly until there are about –150 cells. These cells have not become specialized.

25. Chapter 9
Cellular Reproduction
9.3 Cell Cycle Regulation
Adult Stem Cells
Found in various tissues in the body and might be used to maintain and repair the same kind of tissue
Less controversial because the adult stem cells can be obtained with the consent of their donor
Cellular Reproduction

26. 10.1 Meiosis Chapter 10 Sexual Reproduction and Genetics
Chromosomes and Chromosome Number
Human body cells have 46 chromosomes
Each parent contributes 23 chromosomes
Homologous chromosomes—one of two paired chromosomes, one from each parent

27. 10.1 Meiosis Chapter 10 Sexual Reproduction and Genetics
Chromosomes and Chromosome Number
Same length
Same centromere position
Carry genes that control the same inherited traits

28. Haploid and Diploid Cells
Chapter 10
Sexual Reproduction and Genetics
10.1 Meiosis
Haploid and Diploid Cells
An organism produces gametes to maintain the same number of chromosomes from generation to generation.
Human gametes contain 23 chromosomes.
A cell with n chromosomes is called a haploid cell.
A cell that contains 2n chromosomes is called a diploid cell.

29. The sexual life cycle in animals involves meiosis.
Chapter 10
Sexual Reproduction and Genetics
10.1 Meiosis
Meiosis I
The sexual life cycle in animals involves meiosis.
Meiosis produces gametes.
When gametes
combine in fertilization, the number of
chromosomes is restored.

30. 10.1 Meiosis Chapter 10 Sexual Reproduction and Genetics
Stages of Meiosis I
Reduces the chromosome number by half through the separation of homologous chromosomes
Involves two consecutive cell divisions called meiosis I and meiosis II

31. 10.1 Meiosis Chapter 10 Sexual Reproduction and Genetics Meiosis I
Interphase
Chromosomes replicate.
Chromatin condenses.
Interphase

32. 10.1 Meiosis Chapter 10 Sexual Reproduction and Genetics Meiosis I
Prophase I
Pairing of homologous chromosomes occurs.
Each chromosome consists of two chromatids.
Prophase I
The nuclear envelope breaks down.
Spindles form.

33. Crossing over produces exchange of genetic information.
Chapter 10
Sexual Reproduction and Genetics
10.1 Meiosis
Meiosis I
Prophase I
Crossing over produces exchange of genetic information.
Crossing over—chromosomal segments are exchanged between a pair of homologous chromosomes.

34. 10.1 Meiosis Chapter 10 Sexual Reproduction and Genetics Meiosis I
Metaphase I
Chromosome centromeres attach to spindle fibers.
Metaphase I
Homologous chromosomes line up at the equator.

35. 10.1 Meiosis Chapter 10 Sexual Reproduction and Genetics Meiosis I
Anaphase I
Homologous chromosomes separate and move
to opposite poles of the cell.
Anaphase I

36. 10.1 Meiosis Chapter 10 Sexual Reproduction and Genetics Meiosis I
Telophase I
The spindles break down.
Telophase I
Chromosomes uncoil and form two nuclei.
The cell divides.

37. 10.1 Meiosis Chapter 10 Sexual Reproduction and Genetics Meiosis II
Prophase II
A second set of phases begins
as the spindle apparatus forms and the
chromosomes condense.
Prophase II

38. 10.1 Meiosis Chapter 10 Sexual Reproduction and Genetics Meiosis II
Metaphase II
A haploid number of chromosomes
line up at the equator.
Metaphase II

39. 10.1 Meiosis Chapter 10 Sexual Reproduction and Genetics Meiosis II
Anaphase II
The sister chromatids are
pulled apart at the centromere by spindle
fibers and move toward the opposite poles
of the cell.
Anaphase II

40. 10.1 Meiosis Chapter 10 Sexual Reproduction and Genetics Meiosis II
Telophase II
The chromosomes reach the poles, and
the nuclear membrane and nuclei reform.
Telophase II

41. 10.1 Meiosis Chapter 10 Sexual Reproduction and Genetics Meiosis II
Cytokinesis results in four haploid cells, each with n number of chromosomes.
Cytokinesis

42. Chapter 10
Sexual Reproduction and Genetics

43. 10.1 Meiosis Chapter 10 Sexual Reproduction and Genetics
The Importance of Meiosis
Meiosis consists of two sets of divisions
Produces four haploid daughter cells that are not identical
Results in genetic variation

44. Chapter 10
Sexual Reproduction and Genetics

45. Meiosis Provides Variation
Chapter 10
Sexual Reproduction and Genetics
10.1 Meiosis
Meiosis Provides Variation
Depending on how the chromosomes line up at the equator, four gametes with four different combinations of chromosomes can result.
Genetic variation also is produced during crossing over and during fertilization, when gametes randomly combine.

46. 10.1 Meiosis Chapter 10 Sexual Reproduction and Genetics
Sexual Reproduction v. Asexual Reproduction
Asexual reproduction
The organism inherits all of its chromosomes from a single parent.
The new individual is genetically identical to its parent.
Sexual reproduction
Beneficial genes multiply faster over time.