1. Reproduction

2. DNA in the Nucleus Chromatin ~ DNA coated in protective proteins.
Chromosome ~ Chromatin that has been copied and coiled up into an X shape to prepare for cell division.
Parts of a chromosome:
Histones
Centromere
Sister Chromatids

3. Sister Chromatids Two complete copies of DNA joined at the centromere.
Copy is made by replication.
Homologues ~ Each sister chromatid contains the same genetic information.

4. Diploid ~ Describes a cell that has two of each kind of chromosome (homologous pairs). Normal body cells are diploid. 2n
Humans 2n = 46
Haploid ~ A cell that has one of each kind of chromosome. Gametes (sex cells) are haploid. N
Humans n = 23
Homologous pairs ~ Chromosomes occur in pairs. Both chromosomes will carry similar information. One came from the father, the other came from the mother.

5. Types of Reproduction Asexual Produces somatic cells (body cells)
Produces diploid cells
Makes clones
Cells are made by
Sexual
Produces gametes (sex cells)
Produces haploid cells
Makes offspring that are genetically different from the parents.
Cells are made by

6. Asexual Reproduction ~. Reproduction that does
Asexual Reproduction ~ Reproduction that does not require the exchange of DNA. There is only one parent, and the offspring will be clones (have the same DNA) of the parent.
1. Fragmentation
2. Budding
3. Spores

7. Mitosis Terms
Parent cell
Spindle
Daughter cell

8. Onion cells in interphase
The Cell Life Cycle:
Interphase
Mitosis
Prophase
Metaphase
Anaphase
Telophase
Cytokinesis
Onion cells in interphase

9. Interphase: The “living” stage.
Interphase: A cell is carrying out normal functions for homeostasis. At the end, replication of DNA occurs, and the cell is called a “Mother” cell.
Onion cells in interphase.

10. Prophase: The 1st phase of Mitosis
Nuclear Membrane Dissolves
Chromatin coils up into chromosomes
Centrioles move to opposite sides of cell and form spindle
Onion Cell in Prophase: Note that the nuclear material is spreading out, due to the dissolution of the nuclear membrane.

11. Metaphase: 2nd Phase of Mitosis
Chromosomes line up on center of spindle.
Onion cell in metaphase: The chromosomes are gathered in the middle

12. Anaphase: 3rd Stage in Mitosis
Anaphase: The chromosomes split into separate sister chromatids, and move to opposite centrioles
Onion Cell in anaphase: Each chromatid is dragged to opposite sides.

13. Telophase: Last stage of Mitosis
Two new nuclear membranes form.
Spindle dissolves.
Chromatids uncoil into chromatin.
Onion Cell in telophase: The chromosomes are in 2 separate nuclei in the same cell.

14. Cytokinesis: Cell splits into two daughter cells.
Daughter cells of onion
Cytokinesis (fission): After two nuclei have formed, the mother cell divides to form 2 daughter cells.
Fish cells undergoing cytokinesis

15. Differences in Plant and Animal Cell Mitosis
Plant Cells
No centrioles
Formation of cell plate in telophase
Animal Cells
Centrioles form spindle
Cleavage furrow develops in telophase

16. Sexual Reproduction ~ Reproduction that requires the exchange of DNA between two members of the same species. The offspring will have DNA that combines genes from both parents, but will be unique to the offspring.
Haploid
Gametes
Sperm
Ovum

17. Meiosis Two divisions, no replication of DNA in between.
Chromosomes will exchange pieces to ensure genetic diversity of offspring.
Resulting cells will be haploid gametes.

18. Meiosis ~ Process by which haploid cells are produced.
Spermatogenesis ~ Meiosis that produces four new sperm cells from one mother cell.
Oogenesis ~ Meiosis that produces one new ovum from one mother cell.

19. Meiosis I Prophase I ~ Same events as in prophase of mitosis, except:
Crossing over ~ Pairs exchange pieces with each other.
Chiasmata ~ Sites on chromosomes where crossing over occurs.
Metaphase I ~ Homologous pairs line up on metaphase plate. Centromeres of each are attached to separate centrioles.
Anaphase I/Telophase I ~ Pairs separate, and intact chromosomes are pulled to opposite poles. Spindle dissolves, new nuclear membranes form. Cell divides.

20. Meiosis II
Prophase II ~ (No DNA duplication has occurred!) New spindle forms, nuclear membrane dissolves.
Metaphase II ~ Chromosomes line up.
Anaphase II ~ Centromeres break, daughter chromosomes move to opposite sides.
Telophase II ~ Same as mitosis. Cells are haploid.
Spermatogenesis ~ 4 viable daughter cells.
Oogenesis ~ 3 commit apoptosis, only one continues.

21. Cell Development Fertilization Zygote Embryo
Cell differentiation ~ Process in which a developing cell is specialized. Genes are selectively “turned off” to determine the cell type.