Name ________________________
BGY 30 - GENETICS
MITOSIS, MEIOSIS, AND KARYOTYPE LABORATORY

1. Draw a Giant Chromosome. Label euchromatin, heterochromatin, and chromocenter.     (5 Points)









     a. How do polytene chromosomes form? (5 Points)





     b. Describe the functional activity of dark and light bands. (5 Points)






2. Draw the stages of mitosis as seen in the onion root tip. (Use back, if necessary.)
    (5 Points)















3. How many genetically different gametes can one person produce?




     How many different zygotes can two people make? (10 Points)





4. a. Using the symbols YY for the purple kernels and yy for the yellow kernels, show the         genotype of the F1 generation. (5 Points)





    b. What would be the phenotype of the F1 generation? (5 Points)






5. a. What would be the genotypes and their ratios from a cross between two F1          individuals? (5 Points)





    b. What would be the phenotypes and their ratios from a cross between two F1
         individuals? ( 5 Points)





6. Count the kernels on one ear of corn. (10 Points)

          Number of Purple Kernels ________________

          Number of Yellow Kernels_________________

     Does this data fit the expected Mendelian phenotype ratio?



     Use a Chi-Square test to support your answer.










7. What letter was on your Karyotype sheet? __________

    What was the karyotype of your patient?_________________________________

    How did you reach this conclusion?



    What are the physical manifestations of this genetic disorder? (10 Points)






    Attach your completed karyotype sheet. (10 Points)


8. Write a formula for a: (10 Points)
     a. male with Down syndrome (due to the presence of an extra chromosome 21)



     b. female with Turner Syndrome (only one X chromosome)



    c. female with cri du chat syndrome (deletion of a portion of p arm of chromosome 5



    d. male with Klinefelter Syndrome (two X chromosomes and one Y chromosome)



     e. female with a Philadelphia chromosome (translocation between chromosomes 9
         and 22). People suffering from a form of leukemia (chronic myeloid leukemia)
         frequently harboring cells containing the Philadelphia chromosome.




9. DISCUSSION QUESTION: Abnormalities in chromosome number are detrimental
    and usually lethal. Speculate as to why the impacts of abnormal number in
    chromosome 21 and in the X chromosome are relatively mild. (10 Points). [HINT:
    USE YOUR TEXTBOOK AS A REFERENCE - LOOK UP DOWN'S AND
    SEX  CHROMOSOMES]

Click here to display the Karyotype Worksheet needed during the lab period.