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BIOLOGY CONCEPTS & CONNECTIONS Fourth Edition Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Neil A. Campbell • Jane B. Reece • Lawrence G. Mitchell • Martha R. Taylor From PowerPoint ® Lectures for Biology: Concepts & Connections CHAPTER 8 The Cellular Basis of Reproduction and Inheritance Modules 8.19 – 8.23
084 Cellular Basis of Reproduction
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PowerPoint PresentationCopyright © 2003 Pearson Education, Inc.
publishing as Benjamin Cummings
Neil A. Campbell • Jane B. Reece • Lawrence G. Mitchell • Martha R.
Taylor
From PowerPoint® Lectures for Biology: Concepts &
Connections
CHAPTER 8
Modules 8.19 – 8.23
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin
Cummings
8.19 A karyotype is a photographic inventory of an individual’s
chromosomes
To study human chromosomes microscopically, researchers stain and
display them as a karyotype
A karyotype usually shows 22 pairs of autosomes and one pair of sex
chromosomes
ALTERATIONS OF CHROMOSOME NUMBER AND STRUCTURE
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin
Cummings
Preparation of a karyotype
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin
Cummings
8.20 Connection: An extra copy of chromosome 21 causes Down
syndrome
This karyotype shows three number 21 chromosomes
An extra copy of chromosome 21 causes Down syndrome
Figure 8.20A, B
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin
Cummings
The chance of having a Down syndrome child goes up with maternal
age
Figure 8.20C
8.21 Accidents during meiosis can alter chromosome number
Abnormal chromosome count is a result of nondisjunction
Either
homologous
Figure 8.21B
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin
Cummings
Fertilization after nondisjunction in the mother results in a
zygote with an extra chromosome
Figure 8.21C
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin
Cummings
8.22 Connection: Abnormal numbers of sex chromosomes do not usually
affect survival
Nondisjunction can also produce gametes with extra or missing sex
chromosomes
Unusual numbers of sex chromosomes upset the genetic balance less
than an unusual number of autosomes
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin
Cummings
Table 8.22
A man with Klinefelter syndrome has an extra X chromosome
Figure 8.22A
Poor beard
Figure 8.22B
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin
Cummings
8.23 Connection: Alterations of chromosome structure can cause
birth defects and cancer
Chromosome breakage can lead to rearrangements that can produce
genetic disorders or cancer
Four types of rearrangement are deletion, duplication, inversion,
and translocation
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin
Cummings
Figure 8.23A, B
Figure 8.23C
Chromosome 9
A chromosomal translocation in the bone marrow is associated with
chronic myelogenous leukemia
Chromosome 22