1. About two trillion cells are produced by an adult human body every day!

2. Cell Division Occurs in humans and other organisms at different times in their lives. Also known as cell reproduction.

3. Why do cells divide?

4. Stores info and tells the cells when to make proteins, and what kind to make.

7. Chromosomes Chromatids - one of two duplicated, joined, identical parts of a chromosome; found after DNA replication but before cell division. Centromere – Point at which sister chromatids are attached

8. Gene Centromere Chromatid Chromosome DNA supercoil

12. Sperm Cell n = 23 Egg cell n = 23 Zygote 2n = 46 Haploid cells ! Diploid cells!

13. Changes in chromosome number

14. Monosomy 21 Trisomy 21

15. chromosomes that are not directly involved in determining the sex of an individual.

16. A gamete is an organism’s reproductive cell. Two examples: EGG SPERM All cells other than gamete cells are somatic cells!

17. Sex chromosomes

18. Male Female