Glencoe Biology

71 Pages·2009·4.15 MB·English

Chapter 10 Sexual Reproduction
and Genetics
Section 1: Meiosis
Section 2: Mendelian Genetics
Section 3: Gene Linkage and Polyploidy
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Chapter 10 Sexual Reproduction and Genetics
10.1 Meiosis
Chromosomes and Chromosome Number
(cid:131) Human body cells have 46 chromosomes
(cid:131) Each parent contributes 23 chromosomes
(cid:131) Homologous chromosomes—one of two
paired chromosomes, one from each parent
Chapter 10 Sexual Reproduction and Genetics
10.1 Meiosis
Chromosomes and Chromosome Number
(cid:131) Same length
(cid:131) Same centromere position
(cid:131) Carry genes that control
the same inherited traits
Chapter 10 Sexual Reproduction and Genetics
10.1 Meiosis
Haploid and Diploid Cells
(cid:131) An organism produces gametes to maintain the
same number of chromosomes from generation
to generation.
(cid:131) Human gametes contain 23 chromosomes.
(cid:131) A cell with n chromosomes is called a haploid
cell.
(cid:131) A cell that contains 2n chromosomes is called a
diploid cell.
Chapter 10 Sexual Reproduction and Genetics
10.1 Meiosis
Meiosis I
(cid:131) The sexual life cycle
in animals involves
meiosis.
(cid:131) Meiosis produces
gametes.
(cid:131) When gametes
combine in fertilization, the number of
chromosomes is restored.
Chapter 10 Sexual Reproduction and Genetics
10.1 Meiosis
Stages of Meiosis I
(cid:131) Reduces the chromosome number by half
through the separation of homologous
chromosomes
(cid:131) Involves two consecutive cell divisions
called meiosis I and meiosis II
Chapter 10 Sexual Reproduction and Genetics
10.1 Meiosis
Meiosis I
(cid:131) Interphase
(cid:131) Chromosomes replicate.
(cid:131) Chromatin condenses.
Interphase
Chapter 10 Sexual Reproduction and Genetics
10.1 Meiosis
Meiosis I
(cid:131) Prophase I
(cid:131) Pairing of homologous
chromosomes occurs.
(cid:131) Each chromosome consists of two Prophase I
chromatids.
(cid:131) The nuclear envelope breaks down.
(cid:131) Spindles form.
Chapter 10 Sexual Reproduction and Genetics
10.1 Meiosis
Meiosis I
(cid:131) Prophase I
(cid:131) Crossing over produces exchange of genetic
information.
(cid:131) Crossing over—chromosomal segments are
exchanged between a pair of homologous
chromosomes.