Download Ch 14-2 DR

Name ________________________________________________________________Hour________
Chapter 14-2 Directed Reading
1. How many base pairs does a human diploid cell contain?_________________________________
2. About how much of the DNA in your chromosomes are genes?______________________________
3. How many base pairs does a single gene contain? _____________________
How many in the largest human genome?________________
4. Chromosome 22 is one of the ____________________human autosomes, and contains _____________
different genes, some of which are very important to your________________________?
5. Name two genetic disorders associated with chromosome 22.
a.
b.
6. Describe the sites on chromosome 22 where rearrangement occurs.____________________________
7. What is a genetic disorder associated with chromosome 21? _________________________________
Who was it named after?___________________
What are some symptoms?__________________
8. Genes located on the X and Y chromosomes are said to be sex-linked, explain why.________________
_____________________________________________________________________________________
9. Compare and contrast the X and Y chromosomes. __________________________________________
Who has them?_______________________________
Their relative sizes.X= ________________ Y=____________
# of genes.X=_____________Y=________________
10. Where is the gene for color blindness located?________________________________________
11. Explain why color blindness is rare in females.________________________________________
12. Why are males affected with recessive disorders even if they only have one recessive allele?
____________________________________________________________________________________
13. What has to happen for a female to be affected by a recessive disorder?
____________________________________________________________________________________
14. What are symptoms of hemophilia?_____________________________________________________
Who gets it? _______________________
How can it be treated?_____________________________________________________________
15. What are symptoms of Duchenne Muscular Dystrophy?_____________________________________
Who gets it?________________________________
What causes it?_____________________________
What is a possibility of treatment or cure?______________________________________
16. How do female cells adjust to the extra X chromosome?____________________________________
What is produced as a result?______________________________________________________
17. What can happen to cat’s fur when X chromosomes randomly turn off in different regions in:
Male cats__________________________________
Female cats________________________________
18. What can you tell about a cat by the number of different colors its fur is?_______________________
19.The most common error in meiosis is when__________________________________________
20. How does nondisjunction cause chromosome number disorders?______________________________
____________________________________________________________________________________
21. What is trisomy?______________________________
What causes it?______________________________
22. The most common trisomy occurs on chromosome # ______ and is known as ___________________.
23. What are some symptoms of the trisomy named in number 22?_______________________________
_____________________________________________________________________________________
24. Why is it important for scientists to know where each gene is located on the chromosomes?
_____________________________________________________________________________________
25. Look at figure 14-16. How can looking at this karyotype tell you this karyotype belongs to a person
with Down’s syndrome?________________________________________________________________
Is this person male or female?____________
26. What can nondisjunction in females lead to?______________________________________________
How does it occur?_________________________________________________________________
What are effects?___________________________________________________________________
What does the karyotype 45, X tell us about this person?___________________________________
27. What can nondisjunction in males lead to?_____________________________________
How does it occur?_______________________________________________________
What are effects?_________________________________________________________
What does the karyotype 47,XXY tell us about this person?_______________________
28. What is contained within Y chromosomes that is important to males?___________________
What happens if it is missing?__________________________________________________