Download Ch. 11 Meosis-2010

Ch. 11 Meiosis
Chapter Packet
Name ______________________
Period ______
California State Standards covered by this chapter:
Genetics
2. Mutation and sexual reproduction lead to genetic variation in a population. As a basis for understanding this
concept:
a. Students know meiosis is an early step in sexual reproduction in which the pairs of chromosomes
separate and segregate randomly during cell division to produce gametes containing one
chromosome of each type.
b. Students know only certain cells in a multicellular organism undergo meiosis.
d. Students know new combinations of alleles may be generated in a zygote through the fusion of male
and female gametes (fertilization).
e. Students know why approximately half of an individual's DNA sequence comes from each parent.
Read the appropriate section in the textbook and read the online lecture notes before answering the
following questions. You must put all answers and definitions in your own words for full credit.
Chromosome Number
1. gene:
2. Where are genes located?
3. homologous chromosomes:
4. In humans, a typical body cell has _______ chromosomes or ______ matched pairs.
5. diploid cell:
6. The diploid number of a human body cell is ________.
7. gamete:
8. haploid cell:
9. The diploid number of a cell is represented as __________ while the haploid number is represented
as ___________.
10. Karyotype:
11. Sex chromosomes:
12. Autosomes:
13. Which sex chromosomes does each gender have?
Males:
Females:
Phase of Meiosis
Meiosis differs from mitosis in several important ways…
1)
In meiosis, two nuclear divisions take place instead of one as in mitosis
2)
Because of the reduction division, the daughter cells are haploid. They have only one set of chromosomes.
Mitosis produces daughter cells that are diploid.
3)
Four daughter cells result from these divisions, in contrast to the two daughter cells that result from mitotic cell
division.
4)
Homologous chromosomes pair up side by side during the first meiotic division. This allows for the exchange of
corresponding pieces of DNA (crossing-over), thus distributing a random mixture of maternal and paternal
chromosomes to each gamete (egg or sperm cell). Therefore, the daughter cells are genetically different from
each other and the parent cells.
Telophase I
& Cytokinesis
Anaphase I
Metaphase I
Prophase I
14. Draw the cell stage and then describe the key events that occur during the stage.
Meiosis I
15. What is the end result of Meiosis I?
Telophase II
& Cytokinesis
Anaphase II
Metaphase II
Prophase II
16. Draw the cell stage and then describe the key events that occur during the stage.
Meiosis II
17. What is the end result of Meiosis II?
18. When does crossing over occur during meiosis?
19. What is the result of crossing over between homologous chromosomes?
Gamete formation
20. In male animals, the gametes are called ________________________.
21. In female animals, the gametes are called ________________________.
22. Gametogenesis is the production of gametes. There are some significant differences between
gametogenesis in males and females. Read the section on gamete formation on page 278 in your text
book. Complete the diagrams by drawing what happens to the chromosomes during meiosis for the
formation of sperm cells (Spermatogenesis) and egg cells (Oogenesis).
2N = 4
Chromosomes shown after
Interphase and after DNA
replication
End Result
Meiosis I
End Result
Meiosis II
Sperm Cells
Egg
Cell
(ovum)
Polar bodies
23. Oogenesis is the process that produces eggs. Where in the female are eggs produced?
24. Spermatogenesis is the process that produces sperm cells. Where in the male are sperm cells
produced?
25. The haploid number of a human egg or sperm cell is ________.
26. In humans, a haploid sperm cell from the father fuses with a haploid egg cell of the mother in the
process of ________________________.
27. The resulting fertilized egg is called a _________________.
28. If a single diploid cell with 24 chromosomes undergoes meiosis and produces sperm, the result will be
_________ sperm cells, each with __________ chromosomes.
29. polar body:
30. How is a polar body created?
Comparing Mitosis and Meiosis
Compare the two processes of mitosis and meiosis by completing the table below. Read each
characteristic and make short jot notes discussing any important differences, similarities or events
occurring in each process. Please note that yes or no answers are not appropriate.
CHARACTERISTIC
Function/purpose of process in the
life cycle of a cell/organism
Type of reproduction
Types of cells that undergo the
process (areas of the body)
Types of cells produced by the
process
Genetic make up of the parent cell
(2N/N)
Behavior of homologous
chromosomes during
prophase/prophase I
Behavior of homologous
chromosomes during metaphase
Number of nuclear divisions
Number of times DNA is replicated
Number of time cytokinesis occurs
Number of daughter cells
produced at the end of the process
Genetic make up of daughter cells
(2N/N)
MITOSIS
MEIOSIS