1. 3-5-10 IN
What are gametes?
Define Meiosis

2. 3-05-10 Through OUT Read 498-502 Complete the meiosis worksheet
Genetic disorders
Explain Part A pg. 431
OUT
Read
Complete the meiosis worksheet

3. 5. In cocker spaniels, black B is dominant over red b
5. In cocker spaniels, black B is dominant over red b. Solid color S is dominant over white spotting s. A red male was mated to a black-and-white female. They had five puppies, as follows: one black, one red, one black and white, and two red-and-white.
A. What genetic principle explains the phenotypes of these offspring?
B. Write a one or two paragraphs to describe how that principle worked in this cocker spaniel family. Include the following terms; gene, phenotype, dominant trait, recessive trait, chromosome, allele, genotype

4. Open your book to page 496
With your group divide two genetic disorders between pairs
Read and take notes about your decided disorder
Share your information with the other pair
Check with my notes to see you have all important information

5. Case studies of two genetic disoders
Huntington’s disease- a dominant genetic disorder that causes degeneration of the central nervous system.
Symptoms occur after 35
NO cure
Disease causes the brain and nerves to slowly shutdown for up to 15 years, then person dies
Genotype Hh or HH

6. Cystic fibrosis -- a recessive genetic disorder that affects the respiratory system.
Symptoms show at birth
Lungs are clogged with thick mucus
Affects digestive system as well because of mucus
Possibilities range between races
Genotype cc
NO cure, person usually dies at a young age
However, antibiotics, vapor therapy, and chest thumping help

7. Other genetic disorders to research:
Down syndrome
Sickle-cell

8. Would you test to see if you and your partner carry genetic disorders?
What are the advantages of knowing you have alleles for genetic disorders?
What are the disadvantages of knowing you have alleles for genetic disorders?

9. Understanding Patterns of Inherited Patterns
Gametes -- How genetic information is passed on from one generation to the next
Sperm(male) Egg(Female)
Only have half the information
23 Chromosomes

10. Meiosis --- process that reduces the amount of genetic information in a cell by half.
How gametes are produced
VERY important process, because it reduces the amount of genetic information so that it doesn’t continue to build up
Explains why patterns of inheritance often are predictable

11. Meiosis: The Mechanism behind patterns of inheritance
In all cells(46 chromosomes), chromosomes are in pairs; This is called diploid (2n)
For each pair; one chromosome from mom one chromosome from dad
Gamete(23 chromosomes) only contain 1 chromosome from each pair; This is called haploid (n)

12. MOM n n
DAD
FERTILIZATION 2n

13. MEIOSIS 2n Cell division 1 n n n n n n Cell division 2 Cell division 2
Chromosome from dad n
Chromosome from mom n
DNA synthesis: each chromosome doubles 2n
Cell begins to divide in half
Cell division 1 n n
Cell division 2
Cell division 2 n n n n

14. Before meiosis, each chromosome doubles; DNA synthesis
First cell division occurs and doubled chromosomes separate
Each offspring cell contains one doubled chromosome
Second cell division occurs and doubled cell separates into two cells
Results in a total of 4 offspring cells (daughter)
Each offspring cell contains one chromosome from original pair

15. Principle of segregation --- during meiosis, chromosome pairs separate so that each of the two alleles for any given trait appears in a different gamete. Gg Gg G g g G

16. Watch DVD “Meiosis” and add additional notes to help with you understanding of the concept
Meiosis web animation

17. Tracking Genes through Meiosis
Use figure 11.9, your journal notes, and modeling clay to track how meiosis affects the distribution of the 4 chromosomes.

18. 1. On a large sheet of paper, draw circles to represent a cell undergoing meiosis. On the last set of four circles. Refer to page 500
2. Use modeling clay to form 2 pairs of chromosomes about as thick as a pencil. Make one pair longer than the other.
Red is from female parent
Blue is from male parent

19. 3. Use the letters provided and press them gently into clay.
C= cream eye c= tan eye
W= white wing w=spotted wing
Eye color on long chromosome and Wing color on short chromosome
4. Place your chromosome models in the large circle at the top of your sheet of paper

20. 5. Prior to meiosis, the chromosomes replicate
5. Prior to meiosis, the chromosomes replicate. Make more clay models with labels to represent this step.
6. Using your cell diagram circles, move your chromosome models through the process of meiosis.
In your journal, draw the chart you created

21. 7. Answer the following questions:
A. In your model, what is the genotype of each sperm for eye color and wing color?
B. What other genotypes are possible?
C. At what point would you change how you positioned your chromosome models to obtain the other possible genotypes?

22. Interphase

23. Interphase (synapse)

24. Meiosis I

25. Meiosis II

26. Interphase (synapse)

27. Interphase (synapse)
Crossing-over

28. Meiosis I

29. Meiosis II