Chromosomes, Mitosis Review, and Meiosis Introduction
Name:
Per:
1. What is the purpose of DNA?
2. DNA is built of billions of subunits called __________________________. (if you forget look back in your
unit 5 notes).
Draw a picture of this subunit.
3. What are chromosomes and when do they form?
4. Draw and label the parts a chromosome.
5. Chromosomes consist of two identical ____________ called _______________.
6. DNA_______________________ before cell division so each new cells will each receive one complete copy
of DNA.
7. Why does a cell go through mitosis?
8. What cells in a human go through mitosis?
9. What is meiosis?
10. A. If an organism has a diploid, or 2n, number of 16, how many chromosomes would its sperm and egg
cells contain?
b. Horses have 32 chromosomes in their sex cells. How many chromosomes in their somatic cells?
11. Fill in the following chart
number of
number of
chromosomes
species
diploid
in haploid
chromosomes
cells
(sperm/egg)
human
2n=46
fruit fly
2n=8
monkey
n=21
king
2n=104
crab
petunia
n=7
rice
n=12
12. Dogs have 78 chromosomes in their diploid/somatic cells. How many chromosomes are in their
haploid/sex cells (sperm and egg)?
13. Why do we need meiosis?
14. What is the purpose of having half the number of chromosomes in gametes?
15. Why is it beneficial to have genetic diversity in a population of organisms?
16. Where does meiosis take place?
Meiosis and Karyotypes
Name:
1. What is meiosis?
2. What type of cell undergoes meiosis?
3. Meiosis produces ______ (#) reproductive cells called sex cells or ____________________.
4. Are the cells produced in meiosis diploid or haploid? ___________________
5. What is the name of the gametes for males and females in humans? Tell their chromosome number.
6. What is the diploid chromosome number for humans? ____________ Haploid?__________
7. What are homologous chromosome pairs?
8. Do homologous chromosomes pair during mitosis or meiosis?
9. The fusion of a sperm and an egg is called ________________________. It produces a
________________ with 46 (2n) chromosome number.
10. Cells starting mitosis and meiosis begin with a ____________________ (haploid/diploid) set of
chromosomes. After meiosis, cells contain a_____________________ (haploid/diploid) number of
chromosomes.
12. Compare and Contrast mitosis and meiosis in the chart below
mitosis
meiosis
13. Explain why it is beneficial for an organism to reproduce sexually (with gametes) over asexually.
14. What is a gene?
Per:
15. What is genetic recombination?
16. Describe two ways in which genetic recombination occurs during meiosis? Explain each!
17. Sketch and color a picture of chromosomes during crossing-over.
18. Genetic recombination results in genetic _______________________________.
19. How many cells form at the end of Meiosis II and how many chromosomes do they contain?
20. In humans, meiosis occurs in the ___________________ and in the __________________
producing cells called ________________________
21. The picture below is an image known as a __________________________. What is the purpose of this?
22. Chromosome pairs #1-22 are known
as _____________________________
23. The 23rd pair of chromosomes codes for
the gender of an organism. Looking at the
23rd pair on this karyotype, the gender is
_______________________________