1. LEQ: How do eukaryotic cells divide?
Key terms – interphase, chromosome, chromatin, phases of mitosis (various), cytokinesis
Reading 5.3

2. LEQ: How do eukaryotic cells divide?
Activator:
During which stage of the cell cycle is DNA copied? Explain how this process occurs.

4. Chromosomes condense at the start of mitosis.
A chromosome is a DNA molecule associated with protein.
DNA wraps around histone proteins that condense it.
DNA double helix
DNA and histones
Chromatin
Supercoiled DNA
Chromosomes come in duplicated and unduplicated forms

5. Chromatin – DNA coiled around histone proteins
chromatid
telomere
centromere
Condensed, duplicated chromosome
Chromatin – DNA coiled around histone proteins
Chromatid - One half of a duplicated chromosome
Sister chromatids (duplicated, right) - are held together at the centromere.
Telomeres (ends) - protect DNA and do not include genes.

7. Focus on Mitosis:
The nucleus – when is it disassembled, when does it reappear?
Chromosomes – how do they move, when do chromatids separate?
Mitotic Spindle – how does it assist in mitosis?

8. Interphase prepares the cell to divide. G1 S G2
Mitosis and cytokinesis produce two genetically identical daughter cells in many eukaryotes.
Parent cell
centrioles
spindle fibers
centrosome
nucleus with
DNA
Interphase prepares the cell to divide. G1 S G2

9. Mitosis divides the cell’s nucleus in four phases:
Prophase - chromosomes condense, nucleus disassembles, spindle fibers form.

10. Metaphase - chromosomes line up in the middle of the cell.

11. Anaphase: sister chromatids separate, move to opposite sides of the cell.

12. Focus: Anaphase chromosomes

13. Telophase - nuclei form, spindle disassembles and chromosomes begin to uncoil.

14. Cytokinesis differs in animal and plant cells.
Animals: the membrane pinches closed.
Plants: a cell wall forms.

18. A look ahead: Lab Interphase “I-ball” Parent cell centrioles
spindle fibers
centrosome
nucleus with
DNA

19. Prophase
“pile”

20. Metaphase
“middle”

21. Anaphase
“apart”

22. Telophase
“two piles”

23. Summary:
Briefly explain why the daughter cells resulting from binary fission and mitosis are genetically identical to each other and to the original cell.
How does mitosis accomplish the production of daughter cells.
Be sure to address how genetic information is acquired

24. Answers:
Daughter cells are clones, the genetic information of the parent cell was copied and condensed into duplicated chromosomes, each consisting of two identical DNA molecules (sister chromatids). The chromatids are then separated during metaphase so that when the daughter cells begin to assemble their nuclei, each will have received a complete copy of the parent cell’s genetic information.
Prophase and telophase are opposites. The nuclear envelope fragments, chromosomes condense, and spindle fibers start to assemble in prophase. In telophase, the reverse occurs: the nuclear envelope reforms, chromosomes uncoil, and spindle fibers disassemble.