1. Oct 24, 2016
Asexual Reproduction

2. Humans have 46 chromosomes in each cell of their body
*** Humans have 46 chromosomes in each cell of their body*** (except sex cells which have 23)
Sperm and Egg Cells

3. Asexual Reproduction
Formation of a new cell from a single cell
Happens through mitosis
New cell has the exact same DNA as the parent cell

4. Produces genetically identical offspring
Effective method to quickly produce new cells that are exactly the same as the parent cells

5. Happens in every cell in the human body, except in the ovaries and testes where sex cells are made (ex: making new skin cells happens by asexual reproduction)

6. Mitosis Diagram:
Cell divides to make 2 identical cells with 46 chromosomes in each

7. There are different types of asexual reproduction.

8. Sexual Reproduction
Humans use sexual reproduction to make their offspring

9. In general, less complex organisms produce offspring by asexual reproduction, while more complex organisms produce offspring by sexual reproduction

10. Sexual Reproduction
Formation of a new cell from 2 different parent cells (sperm and egg)
New cell is genetically different than the parents
Happens by meiosis

11. 4 new cells are made
23 chromosomes in each new cell

12. DNA in new cells is different than the parent cell DNA

13. Because the genetic information is combined from 2 different parents, there is a completely new genetic code for the offspring
Gives us variation (differences in our characteristics)

14. This is the reason why we look different than our parents and our siblings
Produces unique, non-identical individuals

15. We have 46 chromosomes in each cell of our body (except for the gametes – sperm & egg)
Can be sorted into 23 pairs
Each of the 23 pairs has the same information, and we call them homologous pairs

16. Gametes
Specialized sex cells
Produced in the female ovaries and male testes in humans
Ex: sperm and egg cells

17. Gametes
Have 23 chromosomes
Need ½ of the genetic information so that when they combine to form a fertilized egg, they make a new cell with a total of 46 chromosomes
Produced by meiosis

18. Another form of cell division
Meiosis
Another form of cell division
Only used in sexual reproduction
Creates gametes with 23 chromosomes in each cell

19. Makes sure that each gamete has a different combination of chromosomes that were present before meiosis
Nuclei of the new individual is not identical to the parents

20. In order for the new individual to have 46 chromosomes, each gamete must have 23 chromosomes
When the egg gets fertilized from the sperm, the 23 chromosomes from the egg connect with the 23 chromosomes from the sperm, to give a total of 46 chromosomes

21. In mitosis, the chromosome number does not change, but in meiosis, gametes are created that have ½ of the original information

22. Meiosis Diagram:
Cell divides to make special gametes with 23 chromosomes in each