1. Cellular Division

2. Chromosomes Chromosome
In a eukaryotic cell, a condensed structure in the nucleus that is made up of DNA
In a prokaryotic cell, the main ring of DNA

3. Chromosomes
Chromatin – genetic material that’s in string-like form when cells grow

4. Chromosomes
Chromatid – one of the two strands of a chromosome that become visible during mitosis and meiosis
Sister chromatids form chromosomes
Chromatid
Sister
Chromatids

5. Chromosomes
Centromere – the region of the chromosome that holds the two sister chromatids together
Chromatid
Sister
Chromatids

6. Chromosomes
Chromosomes can be unduplicated or duplicated

7. Chromosomes
Karyotype – A chart depicting the arrangement of chromosomes of autosomes and sex chromosomes
Autosomes – chromosomes from somatic (body) cells
In each pair, one chromosome comes from each parent
Karyotype is organized by size
In humans, sex chromosomes are the last (23rd) pair

8. Chromosomes Humans have a total of 46 chromosomes Sex chromosomes
44 autosomes and 2 sex chromosomes
Sex chromosomes
X – female
Y – male

10. Male or female karyotype?

11. Cell Cycle
The longest phase of the cell cycle

12. Mitosis Acronym to learn order of mitotic division (or the M phase)
P Prophase
M Metaphase
A Anaphase
T Telophase
Mitosis – the division of the nucleus

13. Interphase Interphase is NOT a part of mitosis
The cell grows in this phase

14. Interphase Centrioles becomes visible DNA present in chromatin form
Nucleus becomes visible

15. 1. Prophase Centrioles begin traveling to opposite ends of the cell
Chromatin wind up to form chromosomes
Centromeres hold chromatids together
Nuclear membrane and nucleolus start to disappear
Centrioles make spindle fibers in late prophase (or prometaphase)

16. 2. Metaphase “Meta” – middle
Chromosomes line up in the middle of the cell
Spindle fiber production concludes
Spindle fibers attach to centromeres

17. 3. Anaphase Spindle fibers pull daughter chromosomes to opposite ends
Cell starts to pull away from itself

18. 4. Telophase and Cytokinesis
Cleavage forms
Pinching in the middle of the two cells
Nuclear membrane reappears
Cytokinesis occurs
The division of cytoplasm

19. 4. Telophase and Cytokinesis
Cell goes back to interphase after telophase and cytokinesis
In plant cells, cell plates form during cytokinesis

21. Mitosis and cytokinesis video

22. Cancer
Apoptosis – A form of cell death in which a programmed sequence of events leads to the elimination of cells
Cancer – uncontrollable cell growth and division
Tumor – a growth that arises from normal tissue but that grows abnormally in rate and structure and lacks a function

23. Cancer A tumor can be benign or malignant
Benign – does not spread to other parts of the body
Malignant – invades nearby healthy tissues and organs

24. Mitosis vs. Meiosis Meiosis Mitosis
One cell divides into four genetically different cells
Gametes – sex cells
Haploid chromosome number – One set of chromosomes
Haploid symbol – n
23 chromosomes in humans
Mitosis
One cell divides into two genetically identical cells
Somatic cells – body cells
Diploid chromosome number – Two sets of chromosomes
Diploid symbol – 2n
46 chromosomes in humans

25. Meiosis

26. Meiosis I Several events occur during prophase I
Homologous chromosomes pair up forming tetrads
Crossing over occurs
Spindle fibers are produced

27. Meiosis I
Homologous chromosome – two chromosomes (one of paternal origin, the other of maternal origin) that are identical in appearance and pair during meiosis

28. Meiosis I
Tetrad (or synapse) – coupled homologous chromosomes form during prophase I
Crossing over – the exchange of genetic material between homologous chromosomes

29. Meiosis I

30. Meiosis II

31. Meiosis video

33. Spermatogenesis The formation of sperm Spermatocyte –
mature sperm cell
Spermatid – immature sperm cell

34. Oogenesis
The formation
of eggs
Oocyte –
mature egg
Ovum - egg

35. Cloning
A cell, cell product, or organism that is genetically identical to the unit or individual from which it was derived
The first cloned mammal was Dolly the sheep
She lived for six years. Normal sheep live for years.

36. Cloning