1. CELL TYPES & CHROMOSOMES

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

3. Humans body cells have chromosomes or pairs.23 46
maternal
paternal

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

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

6. Similar chromosomes are called:
Homologous chromosomes
Homologous chromosomes

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

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

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

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

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

12. Diploid cell
Which cell is diploid? 2n

13. Haploid cell n
Which cell is haploid?

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

15. Fertilization - - - fusion of egg and sperm

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

17. Making Gametes MEIOSIS & CYTOKINESIS

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

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

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

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

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