Name: _____________
Yet Another Chapter 11-4 Review Sheet Key
1. How many divisions occur in meiosis? Is this the same as mitosis? Explain. There are 2
divisions. This is different than mitosis because mitosis only has 1.
2. The original cell that divides by meiosis is diploid or 2n.
3. How many daughter cells can be produced by meiosis? Is this the same as mitosis? Explain. 4
very different haploid daughter cells are formed. This is different than mitosis which produces
only 2 diploid cells identical to the parent cells.
4. What is the chromosome number of the daughter cells produced by meiosis? How does this
compare to the number of chromosomes in the original cell? n or haploid. Original cell was 2n
or diploid.
5. What are the daughter cells called that are produced by meiosis? Name them.
Gametes – Eggs and Sperm
6. Name the 2 types of meiosis.
a. Meiosis I
b. Meiosis II
7. In humans, how many chromosomes are in the original cells that undergoes meiosis? Are they
single or double stranded? 46 double stranded chromosomes
8. After one division, how many chromosomes are in the cells? Are they single or double
stranded? 23 double stranded chromosomes
9. After the second division, how many chromosomes are in the cells? Are they double or single
stranded? 23 single stranded chromosomes
10. Are eggs & sperm haploid or diploid? haploid
11. What process joins the egg & sperm to restore the original chromosome number of the
organism? Sexual reproduction or fertilization
12. When a sperm fertilizes an egg, a new 2n cell forms called the zygote.
13. Homologous chromosomes are pairs of sister chromatids that have the same genes, but may
have different alleles.
14. Meiosis reduces the chromosome number by half, while fertilization restores it.
15. In Meiosis I, what separates? Homologous chromosomes
16. In Meiosis II, what separates? Sister Chromatids
17. Name these stages of Meiosis.
Prophase I
Metaphase I
Metaphase I
Anaphase I
18. Name at least 3 things that happen in Prophase I.
Homologous chromosomes pair up and form a tetrad, spindle fibers form and
attach to the chromosomes, crossing over takes place. Nuclear membrane disappears,
centrioles move to opposite poles
19. Label this picture in 3 different ways.
20. Once tetrads form, what happens to the homologous chromosomes? What is this called?
After the tetrad is formed, they exchange bits and pieces with one another, called crossing
over.
21. Crossing-over results in genetic variation in the offspring.
22. What happens during Metaphase I?
In metaphase I one, the pairs of homologous chromosomes line up at the equator.
23. At the beginning of Meiosis II, each cell has how many homologs of each chromosome?
There is only one of each homolog.
24. The gametes at the end of Meiosis II will have how many copies of a gene for a trait?
Their will be only one copy of a gene.
25. Name the stages in Meiosis II.
Prophase II, Metaphase II, Anaphase II, Telophase II
26. What happens to the sister chromatids during Anaphase II? They are pulled to opposite
poles
27. Meiosis results in 4 haploid cells called gametes that have one copy of each chromosome
and each allele for each gene in different .
Gamete formation
28. Gametogenesis that produces sperm cells is called spermatogenesis.
29. Gametogenesis that produces egg cells is called oogenesis.
30. How many haploid cells after oogenesis will become an egg cell? Only one.
31. What happens to the polar bodies & WHY? Because egg cells require more energy, one egg
gets most of the cytoplasm and the other 3 haploid cells -- called polar bodies--wither and die.
Comparing Mitosis & Meiosis
112. Complete the following table comparing mitosis & meiosis.
Mitosis
Meiosis
Number of Divisions
One
Two
Number of Daughter
Cells
Two
Four
Genetically Identical
Yes
No
Chromosome Number
46
23
Where Occurs
Somatic (Body) Cells
Sex Cells
Role
Make more identical
cells to replace dying
cells, and allow growth
of organism
Make haploid sex cells
with variations in
genetic makeup to take
place in sexual
reproduction.