Chapter 12 ?’s
Key
Read “HACs” on pg. 241 and answer questions 1-4.
1. What does HAC stand for?
a. Human Artificial Chromosomes
2. What essential pieces of the chromosome must be present to withstand several cell divisions?
a. Telomeres, Genomic DNA and Alpha satellite array (centromeric DNA)
3. What is a megabase?
a. 1 millions bases
4. What is the importance of HACs in medicine?
a. ferry healing genes that is missing or abnormal
Polyploidy:
5. How does most polyploidy occur?
a. multiple sperm fertilize the egg
Aneuploidy:
6. What is nondisjunction?
a. a meiotic error that causes Aneuploidy
7. Draw a rough sketch of diagram 12.12.
8. Look at figure 12.12 and explain, in your own words, 2 ways cells can become monosomic or trisomic.
a. nondisjunction at different location of meiosis
Read A Personal Look at Klinefelter Syndrome on pg. 252.
9. Why was it such a relief for Stefan to discover that he has KS?
a. explained many of the difficulties he had gone through
10. What is the notation used to characterize the KS phenotype?
a. 47,XXY
11. List 3 symptoms of KS.
a. small testes
b. depression, anger
c. shy, learning
Read Ashley’s Message of Hope on page 253.
12. What causes Cri-du-chat?
a. part of the short arm of one copy of chromosome number 5 is missing
13. What suggestions are given for parents of a child with 5p- syndrome?
a. seek good doctors, find good schools
14. What suggestions are given for students in the health field?
a. stay current, be sensitive
Read about Translocations starting on page 253.
15. Name and define 2 types of translocations.
a. Robertsonian-short arm of an acrocentric chromosome breaks leaving sticky ends, Reciprocal- 2
different chromosomes change parts
16. Which type has a more negative prognosis and why?
a. Robertsonian because chromosomes often get repeated
17. Answer question number 1 on page 261. (parts a-e)
a. 35 b/c aneuploidy risk is well above 1/250
b. Suzanne Willoughby
c. trisomy 21 is not the only aneuploidy disorder
d. trisomy 16 is more likely than trisomy 21
e. about 2.4 % or more than triple