1. PowerLecture: Chapter 10
Meiosis and Sexual Reproduction

2. Asexual Reproduction ________________________
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3. Sexual Reproduction Involves
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4. Homologous Chromosomes Carry Different Alleles
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5. Sexual Reproduction Shuffles Alleles
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6. anther (where cells that give rise to male gametes originate)
FLOWERING PLANT
anther (where cells that give rise to male gametes originate)
ovules, inside an ovary (where cells that give rise to female gametes originate)
Fig. 10-3a, p.156

7. Chromosome Number
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8. Meiosis: Two Divisions
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9. PROPHASE I METAPHASE I ANAPHASE I TELOPHASE I
MEIOSIS I
newly forming microtubules in the cytoplasm
spindle equator (midway between the two poles)
one pair of homologous chromosomes
plasma membrane
PROPHASE I
METAPHASE I
ANAPHASE I
TELOPHASE I
Fig. 10-5, p.158

10. PROPHASE II METAPHASE II ANAPHASE II TELOPHASE II
there is no DNA replication
between the two divisions
PROPHASE II
METAPHASE II
ANAPHASE II
TELOPHASE II
MEIOSIS II
Fig. 10-5b, p.159

11. Crossing Over _____________________________________________________

12. Effect of Crossing Over
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13. Possible Chromosome Combinations
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14. Possible Chromosome Combinations
2n for humans would be …
223 or…
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15. combinations possible
Possible Chromosome Combinations 1 2 3
combinations possible or or or
Fig. 10-7, p.161

16. Animal Life Cycle multicelled body zygote diploid fertilization
meiosis
haploid
gametes
Fig. 10-8b, p.162

17. Flowering Plant Life Cycle
sporophyte
zygote
diploid
fertilization
meiosis
haploid
gametes
spores
gametophytes
Fig. 10-8a, p.162

18. Oogenesis three polar bodies (haploid) first polar body (haploid)
oogonium (diploid)
primary oocyte (diploid)
secondary oocyte (haploid)
ovum (haploid)
Meiosis I,
Cytoplasmic Division
Meiosis II,
Cytoplasmic Division
Growth
Figure Page 163

19. Spermatogenesis Figure 10-9 Page 163 spermato- gonium (diploid )
primary spermatocyte (diploid)
secondary spermatocytes (haploid)
sperm (mature, haploid male gametes)
spermatids
(haploid)
Spermatogenesis
Meiosis I,
Cytoplasmic Division
Meiosis II,
Cytoplasmic Division
Growth
cell differentiation, sperm formation
Figure 10-9 Page 163

20. Fertilization
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21. each chromosome duplicated during interphase
germ cell
germ cell
each chromosome duplicated during interphase n
MEIOSIS I
separation of homologues
MEIOSIS II
separation of sister chromatids
gametes
gametes 2n
diploid number restored at fertilization
zygote
Fig , p.166

22. Factors Contributing to Variation among Offspring
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23. Crossing Over… a preview taken from Chapter 11

24. Linkage Groups Genes on one type of chromosome travel together
Degree of linkage may vary

25. Full Linkage A B a b x Parents: A B a b AB ab F1 offspring: All AaBb
meiosis, gamete formation
Equal ratios of two types of gametes: A B a b
Figure Page 178
50% AB
50% ab

26. Incomplete Linkage AC ac A C a c x Parents: A C a c F1 offspring:
All AaCc
meiosis, gamete formation A a A a
Unequal ratios of four types of gametes: C c c C
parental
genotypes
recombinant
genotypes
Figure Page 178

27. Crossover Frequency Proportional to the distance that separates genesB C D
Crossing over will disrupt linkage between A and B more often than C and D
In-text figure Page 178

28. Linkage Mapping in Humans
Linkage maps based on pedigree analysis through generations
Color blindness and hemophilia are very closely linked on X chromosome