1. CELL TYPES & CHROMOSOMES

2. Gametes are sex cells (egg & sperm) Somatic cells are body cells

3. Humans body cells have chromosomes or pairs. maternalpaternal 46 23

4. What are these chromosomes called? Sex chromosomes Is this individual a male or female?xy….male

5. Is this individual a male or female?xx…female

6. Homologous chromosomes Similar chromosomes are called: Homologous chromosomes

7. allele for tall Allele for brown eyes Allele for brown hair Allele for short Allele for black hair Allele for brown eyes Allele for straight hairAllele for curly hair How are they similar? They contain alleles for the same trait.

8. Somatic cells/body cells are diploid. Diploid cells (2n) have homologous pairs.

9. A Diploid Cell The chromosomes are in pairs… homologous pairs. A a B E e b maternalpaternal What type of cell is this? Gamete or somatic cell 2n

10. Gametes/sex cells are haploid. Egg and sperm are gametes. Haploid cells (n) have one set of chromosomes.

11. There is one set of chromosomes. A Haploid Cell What type of cell is this? Gamete or somatic cell n Haploid = half Half the chromosomes.

12. Which cell is diploid? Diploid cell 2n

13. Which cell is haploid? Haploid cell n

14. Sexual reproduction involves the union of egg and sperm offspring are genetically unique

15. Fertilization - - - fusion of egg and sperm

16. + +n n =2n = zygote Egg sperm 46 23 =+ Fertilization

17. Making Gametes MEIOSIS & CYTOKINESIS Making Gametes MEIOSIS & CYTOKINESIS

18. Why do cells undergo meiosis? To make gametes, egg and sperm. In which organs? andovariestestes

19. Homologous pairs 2n Body Cells vs Gametes Two sets of chromosomes One set of chromosomes n

20. MEIOSIS 2n n nn n gametes One diploid cell four haploid cells

21. Meiosis halves the number of chromosomes forms four haploid cells, (n) forms gametes --- egg & sperm

22. MEIOSIS 1. prophase I 2. metaphase I 3. anaphase I 4. telophase I 5. prophase II 6. metaphase II 7. anaphase II 8. telophase II There are eight phases in meiosis: Meiosis I - - - Meiosis II - - - Homologous chromosomes separate Sister chromatids separate