1. Mitosis and Meiosis Asexual v. Sexual Reproduction
CELL DIVISION
Mitosis and Meiosis
Asexual v. Sexual Reproduction

2. Cell Division “process where 1 cell splits into 2”
Replaces somatic (body) cells in multicellular organisms
Allows for multicelullar growth
Allows for asexual reproduction in plants

3. Chromosome – rod shaped structure made up
DNA and protein
a. held together by centromere
- holds chromatids together until they
separate during division
b. only found during cell division

5. Chromosome Number
Human/animal chromosomes – sex chromosomes and autosomes
Humans have 46 chromosomes in somatic cells
Karyotype – used to examine an individual’s chromosomes

7. Nondisjuntion Mutation
“failure of chromosome to separate from it’s homologue during meiosis”
One extra or one less chromosome at chromosome location
Monosomy v. Trisomy

8. Examples of Nondisjunction Disorders
Down Syndrome (Trisomy 21)
1. extra chromosome 21
2. Symptoms – muscle
weakness, large forehead, large
tongue, heart defects, short
stature

9. Klinefelters Syndrome 1. male with extra X chromosome (XXY)
2. Symptoms:
infertile, some feminine
characteristics, undersized
testicles
Turners Syndrome
1. single X chromosomes (XO)
2. female appearance, infertile
due to not maturing
sexually

10. Karyotypes of Individuals with Genetic Disorders

11. Detecting Genetic Disorders
Genetic Screening
1. examining a person’s DNA
2. Karyotype
Ways to get a cell sample
1. amniocentesis
2. chorionic villi sampling
Finding deformities
1. ultrasound

12. Haploid Diploid Reproductive cells (sperm and egg)
Somatic cells (body-all other cells)
½ the # of chromosomes (23)
Has ALL chromosomes (46)
half the DNA
Has ALL DNA
N = haploid
2N = diploid

13. Haploid/Diploid Problems
Haploid → Diploid = sex cell → body cell ( x by 2)
Diploid → Haploid = body cell → sex cell ( ÷ by 2)
Diploid → Diploid = body cell → body cell Haploid → Haploid = sex cell → sex cell

14. Practice Problems
Dogs have 42 chromosomes in their diploid cells. How many are in their haploid cells?
If there are 23 chromosomes in a sperm cell, how many would be in the skin cell?
If there are 46 chromosomes in a nerve cell, how many would be in a blood cell?
If there are 23 chromosomes in a sperm cell, how many would be in a human ovum (egg)

15. Cell Division in Prokaryotes
Binary Fision – two identical cells are produced
from one cell
* division in bacteria

16. Budding:

17. Cell Division in Eukaryotes
Mitosis
Meiosis
Asexual Reproduction
Sexual Reproduction
Division of diploid cells (somatic cells)
Division of haploid cells (reproductive cells)
Results in 2 identical daughter cells
Results in 4 haploid daughter cells
1 division
2 divisions

18. Cell Cycle
“series of events leading to cell division”

19. Mitosis Asexual Reproduction
Diploid cells split into 2 identical diploid cells
Allows body cells to be replaced and cells to GROW

20. Phases of Mitosis
1. Prophase

21. 2. Metaphase

22. 3. Anaphase

23. 4. Telophase

24. Cytokinesis

25. Meiosis “sexual reproduction”
Fusing of 2 haploid gametes to form 1 diploid zygote

26. Stages
2 divisions
a. Meiosis I

27. b. Meiosis II

28. Sources of Genetic Variation
Crossing – over
Fertilization
Independent Assortment