Download 9.2, Cellular Reproduction

Cellular Reproduction and Sexual Reproduction
2 Meiosis and Sexual Reproduction
NEW VOCABULARY
Use the terms in the left column to complete the paragraph below.
autosome
A segment of DNA on a chromosome that controls the production of
cell differentiation
a protein is called a
crossing over
copies of each chromosome. A sex cell, or
diploid
.A
Gametes form during
gamete
gamete combines with another is called
, the process by which one haploid
gene
homologous chromosome
nondisjunction
sex chromosome
stem cell
telomere
.
are pairs of chromosomes, one from
haploid
meiosis
, is
, meaning it contains one copy of each chromosome.
fertilization
karyotype
cell contains two
each parent. One of these pairs include the
that determines the individual’s sex. Segments of homologous
chromosomes exchange during Prophase I in a process known as
. Homologous chromosomes consist of sister
chromatids, which sometimes fail to separate properly; this is known
as
. The other 22 pairs of chromosomes
are called
. Chromosomes have protective caps
called
. Homologous chromosomes can be
arranged in a micrograph called a
, according
to size.
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The process by which an unspecialized cell develops into a
specialized cell with a defined structure and function is called
, which produces and maintains a complex
organism.
are a type of cell that can be directed to
become a specialized cell.
Get It?
Compare and contrast sexual and asexual reproduction.
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2 Meiosis and Sexual Reproduction (continued)
Identify three characteristics that are the same in each member of a
pair of homologous chromosomes. Name one thing that is different.
Same
Different
1.
1.
2.
3.
Compare and contrast the phases of Meiosis I and Meiosis II. Sketch
each phase.
Meiosis I
Prophase I
Metaphase I
Anaphase I Telophase I
Description
Sketch
Meiosis II
Prophase II Metaphase II
Anaphase
II
Telophase
II
Description
Analyze the chart above to determine the phase of meiosis when
crossing over can occur. Mark a star on the correct phase.
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Sketch
2 Meiosis and Sexual Reproduction (continued)
Get It? Distinguish between homologous chromosomes and sister
chromatids.
Compare meiosis and mitosis by filling in the chart below.
Mitosis
Number of DNA replications
Meiosis
Number of cell divisions
Number of daughter cells
Chromosome number of daughter cells
Organize information on how meiosis produces genetic variation.
Meiosis produces
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Compare sexual reproduction and asexual reproduction by
completing the paragraph with the terms below.
• sexual reproduction
• protists
• animals
• genes
• asexual reproduction
• mammals
• plants
• genetic diversity
In
an organism inherits its genetic material
from a single parent. The new organism has the same
as its parent. In
, an organism inherits genetic
material from two different parents. Sexual reproduction increases
, whereas asexual reproduction does not.
, simple
reproduce sexually or asexually.
, and most
can
only reproduce
sexually.
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2 Meiosis and Sexual Reproduction (continued)
Describe telomeres by completing the paragraph.
Telomeres are made of
and
located at
. They are
. Their function is
.
Model a picture showing the ways that nondisjunction during meiosis
can produce a sex cell with an extra copy of a chromosome.
Model a karyotype of a girl with Down syndrome.
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Science Notebook • Cellular Reproduction and Sexual Reproduction
122
2 Meiosis and Sexual Reproduction (continued)
Compare and contrast adult and embryonic stem cells by writing
characteristics in the Venn diagram.
Adult
Both
Embryonic
Get It?
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Describe some ways that adult stem cells can be used to
treat conditions that result from injury or illness.
SUMMARIZE
Analyze how nondisjunction during meiosis could lead to Klinefelter’s syndrome.
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123
2 Meiosis and Sexual Reproduction (continued)
CHECK YOUR PROGRESS
1. Explain how the structure of DNA determines the structure of proteins which carry
out most of the work of cells.
2. Assess how meiosis contributes to genetic variation, while mitosis does not.
3. Illustrate how nondisjunction occurs during meiosis.
4. Summarize the role differentiation plays in the production and maintenance of a
complex organism.
5. Describe a possible application for stem cells.
7. Conduct research on the consequences of nondisjunction other than trisomy 21.
Write a paragraph about your findings.
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6. Compare and contrast mitosis and meiosis by creating a Venn diagram.