1. The Cell Cycle Packet #16
Sunday, December 02, 2018

2. Introduction Recall that reproduction occurs at two levels
Organism
Cellular
This packet investigates asexual cellular reproduction—the cell cycle.
Cell Cycle
An ordered sequence of events in the life of a dividing eukaryotic cell.
12/2/2018

3. Review of the Cell
12/2/2018

4. Review I
Within the nucleus of the cell, is found a structure known as a chromosome.
Chromosome
A linear end to end arrangement of genes and other DNA
Chromosome
Chromatin
DNA Molecules
DNA Strands
Genes
DNA Nucleotides
12/2/2018

5. Ploidy
12/2/2018

6. Haploid vs. Diploid Cells
Ploidy
Number of sets of chromosomes in the nucleus of a cell.
Chromosome set
Total number of chromosomes in the chromosome set
Represented by the letter n
Haploid
A cell having one chromosome set
Human Sperm 1 set of 23 chromosomes
Female Egg 1 set of 23 chromosomes
In human sex cells n, we represent the chromosome set by n
Diploid
A cell having 2 chromosome sets
As an individual, human somatic cells contain 46 chromosomes ( )
In human somatic cells, we represent the sets by 2n (2 * 23 chromosomes)
Sex cells still have 1 set of 23 chromosomes
More on ploidy to come later
Aneuploidy
Euploidy
Sunday, December 02, 2018

7. The Cell Cycle
The Process
12/2/2018

8. Introduction
The cell cycle is a precise duplication of the contents of the parent cell nucleus, followed by an orderly separation of those contents into two new, identical nuclei.
The cell cycle results in two identical daughter cells from one parent cell.
12/2/2018

9. Overview of Cell Cycle Interphase M phase (Mitotic Phase/Mitosis)
G1 phase
Gap phase #1
S phase
DNA synthesis
DNA is duplicated
We will cover this after Mitosis and Meiosis
G2 phase
Gap Phase #2
M phase (Mitotic Phase/Mitosis)
Prophase
Metaphase
Anaphase
Telophase
Cytokensis
Sunday, December 02, 2018

10. Interphase
12/2/2018

11. Interphase
Cell grows and and copies it’s chromosomes in preparation for cell division
Gap Phase 1
Cell grows in size
Synthesis Phase
DNA is synthesized
Chromosomes are duplicated
Gap Phase 2
12/2/2018

12. Mitotic Phase
12/2/2018

13. Mitotic Phase (Mitosis)—Prophase
Longest of mitotic phase
Chromosomes condense and become visible
Chromosomes, once duplicated, are called two sister chromatids
Two chromatids (sister chromatids) are formed by one chromosome
Mitotic spindle assembles
Chromatid
One of the two side-by-side replicas produced by chromosome division
Centromere
Place where chromatids are held together
Sunday, December 02, 2018

14. Mitotic Phase (Mitosis)—Metaphase
Chromosomes align along the middle (equatorial plane) of the cell
Microtubules attach chromosomes to opposite ends of the spindle
Sunday, December 02, 2018

15. Mitotic Phase (Mitosis)—Anaphase
Chromosomes are pulled to the poles of the cell
Sister chromatids are separated
Centromeres divide
Sunday, December 02, 2018

16. Mitotic Phase (Mitosis)—Telophase
Nuclei (nucleus) and, nuclear envelope, reforms in daughter cells
12/2/2018

17. Cell Cycle—Cytokinesis
12/2/2018

18. Cell Cycle—Cytokinesis
Both daughter cells are separated and two distinctive cells are formed.
Daughter cells are pinched off from each other
Sunday, December 02, 2018

19. Review
12/2/2018

20. Review I
Sunday, December 02, 2018

21. Review II
Sunday, December 02, 2018

22. Review III Interphase Prophase Anaphase Telophase Cyctokinesis
DNA is duplicated
Prophase
Chromosomes condense
Anaphase
Sister chromatids separate
Telophase
Nuclei and nuclear envelope reform
Cyctokinesis
Separation of two daughter cells
Sunday, December 02, 2018

23. Review IV One cell division resulting in two daughter cells
Chromosome number, per nucleus, remains the same
Haploid results in haploid
Diploid results in diploid
No crossing over
More on this in meiosis
Sunday, December 02, 2018