1. Meiosis, Karyotypes and Non-Disjunction

2. Meiosis is the process of cell division that forms gametes (sex cells) sperm and eggs. How many chromosomes do humans have In most of their cells? How many chromosomes are in human sex cells? + =

3. Once an egg is fertilized mitosis starts. Mitosis is the process of cell division that Makes somatic cells (body cells). Cells from the fetus can be collected using a process called amniocentesis.

7. Chromosomes line up in the nucleus During the metaphase step of mitosis. Scientists can use a microscope to photograph the chromosomes and use them to make karyotypes.

8. Karyotypes can be used to identify chromosome abnormalities and sex.

9. A Chromosome is made of hundreds or thousands of genes that are made of DNA. Each gene codes for a protein. Centromere: an area Where the 2 chromatids of a chromosome are attached

10. The portion of a chromosome that codes for a trait (made by a a specific protein) is called a ______. next

11. A ________ is a change in the DNA that causes a different shaped _______ to be formed. This protein may not function correctly causing changes in the Organism.

12. next

13. Karyotypes are an organized way to interpret chromosomes How is a karyotype made?

14. To make a karyotype a cell (with its chromosomes visible) is squashed to spread out the chromosomes, then its picture is taken. Scientists match chromosomes looking at length, centromeres, and banding patterns.

15. A karyotype is an organized picture of chromosomes from a cell. Why are some chromosomes numbered and others have letters?

16. What is this organized set of chromosomes called?

17. What is this organized set of chromosomes called? It is a Karyotype.

18. What sex is this normal individual?

19. Is this individual normal? Total number of chromosomes =

20. Is this individual normal? Why? Total number of chromosomes = What is their sex?

21. How do individuals inherit the wrong number of chromosomes?

22. Nondisjuction If nondisjuction occurs in meiosis... gametes may have the wrong number of chromosomes. next These could form a zygote with a monosomyThese could form a zygote with a trisomy y