Mr. HunterBiology Review11/24/2009Cell division, Chromosomesand mutations

Name _______________________ Date ________ Period ________

1. Based on the concept of independent assortment, what are the possible chromosome combinations for a human diploid cell? What is the formula for this calculation? _________

2. When the gamete of one individual unites with a gamete of another individual of the opposite sex, fertilization occurs. What is the number of possible combinations of chromosomes that can be produced by fertilization? ______________ ( show your calculations )

3. If an intestinal cell of a grasshopper contains 24 chromosomes, a grasshopper sperm cell would contain how many chromosomes? ___________ why?

4. A fruit fly somatic cell contains 8 chromosomes. This means that _________ different combinations of chromosomes are possible in its gametes. (show calculations )

5. What are the major differences between mitosis and meiosis?6. You are a doctor at St. Joseph Hospital in Detroit. Your patient is a 39 year old

female who is pregnant. You advise her that she should have prenatal testing (Amniocentesis : small amount of amniotic fluid that surrounds the fetus is removed. This fluid contains fetal cells.) She reluctantly agrees. The karyotype shows an extra copy of chromosome 21. What do you tell your patient about her unborn child? Why did you think this abnormality occurred?

7. Breakage of a chromosome can lead to _______ number of mutations. Describe each mutation. Include a sketch of each type. (pg. 124 Holt Biology as a guide )

8. The DNA content of a diploid cell in the G1 phase of the cell cycle is measured. If this DNA content is represented as 10X, then the DNA content of the same cell at metaphase of meiosis I would be ___________. Explain your answer.

9. What would the DNA content of the same cell be at meiosis II (metaphase)?________ Explain your answer.

10. How does crossing over and independent assortment contribute to genetic variations among offspring?