1. Lectures by David Kass with contributions from John C. Osterman.
PowerPoint® Lecture Presentation for Concepts of Genetics Ninth Edition Klug, Cummings, Spencer, Palladino
Chapter 2
Mitosis and Meiosis
Lectures by David Kass with contributions from John C. Osterman.
Copyright © 2009 Pearson Education, Inc.

2. Figure 2.1

3. What are the differences between prokaryotic and eukaryotic organisms?
Try to come up with 3

4. Name some of the main representative types of organisms in each group
Prokaryotic
Eukayrotic

5. Organisms organize DNA in structures called chromosomes
Organisms organize DNA in structures called chromosomes. Which is prokaryotic, (a) or (b)
(a)
[Default]
[MC Any]
[MC All]

6. Parts of a chromosome

7. The structure labeled 2 is:
centrosome
centromere
centriole
[Default]
[MC Any]
[MC All]

8. The structure labeled:
p arm
monad
q arm
[Default]
[MC Any]
[MC All]

9. Cell Division Prokaryotes Eukaryotes Mitosis +cytokinesis
Binary fission
Eukaryotes
transmission of genetic material from one generation of cells to next involves:
Mitosis +cytokinesis
Meiosis + cytokinesis

10. E. coli – Binary Fission
Figure 2-2 Color-enhanced electron micrograph of E. coli undergoing cell division. Particularly prominent are the two chromosomal areas (shown in red), called nucleoids, that have been partitioned into the daughter cells.
Figure 2.2

11. Section 2.2 – Homologous Chromosomes
In each homologous pair of chromosomes, one member is derived from each parent.
Identify location of:
Sister chromatids
Centromere
Kinetochore
Telomeres
Standford.edu

12. Figure 2-3 Centromere locations and designations of chromosomes based on centromere location. Note that the shape of the chromosome during anaphase is determined by the position of the centromere.
Figure 2.3

13. Diploid vs Haploid Organisms
Diploid Organisms
2 copies of each chromosome for most of its life cycle
Haploid Organisms
1 copy of each chromosome for most of its life cycle
Ex. Bacteria, yeasts and molds, some plants such as bryophytes (mosses)

14. Mechanism of chromosome separation

15. Use the karyotype to identify sex:
Female
Male
[Default]
[MC Any]
[MC All]

16. When Does Mitosis Occur?
Multicellular Organisms
Growth
Tissue repair
Cell replacement of certain tissues (e.g. epidermis – skin)
Single-celled Organisms (prok and euk)
Asexual reproduction

17. Mitosis – two main processes
Karyokinesis
Genetic material is partitioned to daughter cells during nuclear division
Cytokinesis
Cytoplasmic division follows.

18. Cell Cycle

19. Cell Cycle

20. Mitosis Mitosis has discrete stages: (see Figure 2.7) prophase
prometaphase
metaphase
anaphase
telophase
(see Figure 2.7)

21. Figure 2.7

22. Cell-Cycle Regulation and Checkpoints

23. Cyclin-dependent Kinases
Cell cycle is driven by enzymes called Cyclin-dependent kinases, or Cdk’s
Kinases are enzymes that phosphorylate (add a phosphate group to) other proteins
stimulates or inhibits protein’s activity
Cdk’s are active only when they bind to other proteins called cyclins

24. Enzymes Drive the Cell Cycle
Cell division occurs when growth factors bind to cell surface receptors, which leads to cyclin synthesis
Cyclins then bind to and activate specific Cdk’s

25. Activated Cdk’s Promote a variety of cell cycle events
Synthesis and activation of proteins required for DNA
synthesis
Chromosome condensation
Nuclear membrane breakdown
Spindle formation
Attachment of chromosomes to spindle
Sister chromatid separation and movement

26. FIGURE 11-14 The G1 to S checkpoint
Progress through the cell-cycle checkpoints is under the overall control of cyclin and cyclin-dependent kinases (Cdk's). In the G1 to S checkpoint illustrated here, growth factors stimulate synthesis of cyclin proteins, which activate Cdk's, starting a cascade of events that lead to DNA replication.

27. Meiosis
Meiosis reduces the amount of genetic material by one-half to produce haploid gametes or spores containing one member of each homologous pair of chromosomes.

28. Meiosis
Meiosis I and II each have prophase, metaphase, anaphase, and telophase stages (Figure 2.10).

29. Meiosis
Figure 2.10

30. Meiosis
Prophase I has five substages, each including specific events (see Figure 2.9):
leptonema
zygonema
pachynema
diplonema
diakinesis
At the completion of prophase I, the centromeres of each tetrad structure are present on the equatorial plate.

31. Prophase I Additional Terms to Know: Synapse Tetrad Crossing over
Figure 2.9

32. Meiosis I
Metaphase I, anaphase I, and telophase I are similar to those of mitosis.

33. Meiosis
Figure 2.10

34. Meiosis II
During meiosis II, the sister chromatids in each dyad are separated to opposite poles.
Each haploid daughter cell from meiosis II has one member of each pair of homologous chromosomes.

35. Disjunction and Nonjunction
Separation of homologous chromosomes
Nondisjunction
during meiosis I or II leads to gametes with abnormal numbers of chromosomes and can lead to abnormal offspring.

36. 2.5 The Development of Gametes Varies in Spermatogenesis Compared to Oogenesis

37. Section 2.5
Male gametes are produced by spermatogenesis in the testes (Figure 2.11).
Female gametes are produced by oogenesis in the ovary.

38. Figure 2.11

39. Importance of Meiosis
Mechanism of meiosis is basis for production of extensive genetic variation.
Gametes receive either the maternal or the paternal chromosome from each homologous pair of chromosomes.
An organism can produce 2n (where n represents the haploid number) combinations of chromosomes in gametes.

40. Life Cycles Differ in Certain Organisms
Diploid life cycle
Ex. Humans and other animals
Haploid life cycle
Ex. Fungi, protists
Alternation of generation
Plants

41. The End