1. Mitosis and Meiosis

2. Onion (Allium) Root Tip

3. Location of Mitotic Cells on Root Tip
Root cap
Observe cells in the region just above the root cap

4. Stages of Mitosis in Onion Root Tip

5. Whitefish Blastula Mitotic stages

6. Grasshopper Testis

7. Spermatogenesis: Grasshopper Testes Spermatogonia (not yet in meiosis)

8. Primary Spermatocyte in Meiosis I: 2n chromosomes, tetrads
Secondary Spermatocyte in Meiosis II, 1n chromosome, dyads

9. Grasshopper Testis

10. Spermatids, 1n

11. Mature Spermatozoa, 1n

12. Mammalian Testes: Slide #10 p. 3 diagram
Seminiferous tubules: tightly coiled tubules (~ 500 m) where millions of sperm are produced.
Epididymis: sperm travels and matures in a 1-3 week journey.

13. Interstitial space:
Leydig cells  Testosterone

14. Interstitial space:
Leydig cells  Testosterone

15. P. 4 diagram Ascaris Oviduct & Uterus Sperm Penetration
Notice: Sperm head (haploid) have entered the eggs.
Meiosis in the egg can only resume after sperm penetration.
Note the lack of extensive membranes which will be seen to surround the egg later.

16. Ascaris

17. Ascaris

18. Ascaris