1. Cell Reproduction
Chapter 8

2. 8-1 Chromosomes
Cell Reproduction
8-2 Cell Division
8-3 Meiosis

3. DNA: Chromosomes DNA: Centromere Nucleotides Genes
Forms In Eukaryotes:
Chromosome
Coiled DNA
Histone proteins
Nonhistone proteins
Centromere
Chromatin DNA plus protein
Loose storage
Prokaryotes
Single circular molecule
Chromatid
Copy Chromatid
Chromosome

4. **Revisiting DNA** Structure
Nucleic Acid
Nucleotide

5. Chromosome Structure & Numbers
DIPLOID NUMBER

6. DNA Structure Eukaryotic Prokaryotic
Structure of DNA while not replicating  chromatin

7. Types & Organization of Chromosomes
Sex Chromosomes:
2 chromosomes
Determines gender
XX= female
XY= male
Carry genes
Autosomes:
44 chromosomes
All other chromosomes
Homologous Chromosomes
Pairs carrying genes for same trait
Karyotype:
22 pairs homologous autosomes
2 sex chromosomes

8. **Karyotype** What type of organism is this?
What sex is this organism?
Does this organism have any chromosomal abnormalities?

9. Cells & Chromosomes Diploid (2N) Both chromosomes in homologous pair
All cells except reproductive cells
Human:
46 chrom.= 22 autosome pairs+2 sex chrom
Haploid (1N)
One set of chromosomes from pair
Reproductive Cells: sperm & egg= gametes
Sperm + Egg = zygote (2N)
Human
23 chrom= 22 autosomes + 1 sex chrom

10. # of Chromosomes in Various Organismsee
Diploid
Haploid

11. Karyotype Analysis 1. Identify this organism? Identify the gender?
Determine if this is a normal karyotype?

12. II. **Cell Division: Prokaryotes **
Binary Fission:
2 new genetically identical offspring
3 stages
Chromosome copies itself
Cell wall forms between chromosomes
Cell splits

13. Cell Division: Eukaryotes
2 Types:
Mitosis: genetically identical, 2N
Meiosis: genetically different gametes, 1N
Cell Cycle
Interphase = prep!!!
G1 (Gap 1) Phase
S Phase – SYNTHESIS OF DNA
G2 Phase
Or G0 Phase: after G1, exit cell cycle, no division
Mitosis (M phase)
Cytokinesis (C phase)

14. **Cell Cycle**

15. **Mitosis Phases** Prophase Chromosomes form
Nucleolus & nuclear envelope disappear
Centrosomes (contain centrioles) separate to opposite poles of cell
Spindle fibers make mitotic spindle
Kinetochore fibers attach to kinetochore in chromosome
Polar fibers

16. Mitosis Phases Metaphase Anaphase Telophase Cytokinesis:
Chromosomes line up on midline
Anaphase
Chromatids separate “chromosomes”
Telophase
Spindle fibers disappear
Chromosomes chromatin
Nucleolus and nuclear envelope reforms
Cytokinesis:
Cytoplasm divides in telophase
Cleavage furrow in cell membrane
Cell plate: plant cells

17. Mitosis. Diagram http://en. wikipedia

18. **Cytokinesis: Cleavage Furrow & Cell Plate

19. **Meiosis**: Reproductive Cells Only
Forms gametes (1N) from diploid cells (2N)
4 genetically different haploid cells
Meiosis I: haploid cells form by end
Prophase I
Synapsis tetrad
**Crossing over** genetic recombination
Metaphase I
Anaphase I
Independent assortment
Telophase I
Meiosis II:
Prophase, Metaphase, Anaphase, Telophase II

20. **Meiosis I**

21. **Meiosis II (con)**

22. Spermatogenesis In testes
Produces 4 genetically different haploid spermatids
Spermatids mature into sperm

23. Oogenesis In ovaries Produces 1 Egg 3 Polar Bodies Unequal Cytoplasm
Division

24. Spermatogenesis vs Oogenesis

25. **Mitosis vs Meiosis**

26. Asexual & Sexual Reproduction
Offspring from 1 parent
Unicellular mitosis or budding
Multicellular budding
Always genetically identical to parent
Sexual
Offspring results from union of gametes= zygote
Offspring genetically different from parents due to meiosis recombining genes
Allows species to adapt more quickly