ch 13: meiosis & life cycles
TRANSCRIPT
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Ch 13: Meiosis & Life Cycles
If you have 2 sets of chromosomes/cell then you are diploid (2n), but if you have 1 set of chromosomes/cell then you are haploid (1n).
disjunction chromosome number reduction
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Comparison
Increasing genetic variability: Crossing Over
synaptonemal complex
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Increasing genetic variability: Independent Assortment
Example 2n = 4 -> 4 different kinds of chromosome combinations
Increasing genetic variability: Independent Assortment
Example 2n = 6 ->
8 different kinds of chromosome combinations
Thus, the # of possible chromosome combinations after meiosis = 2x, where x = n = # of chromosomes in a haploid cell
So for your cells?
For your offspring’s diploid combination, combine the possibilities from both parents.
46.11
Meiosis: Human Sperm Formation
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46.11
Meiosis: Human Egg Formation
When are mitosis and meiosis used in eukaryotes?
Human (sexual)Life Cycle
Diploid-dominant
Haploid-dominant
Alternation of generations
and some protists and a few fungi
Spores
gametes = sperm, eggs
zygote = fertilized egg
(Note: many eukaryotes also or only use asexual reproduction)
But not all eukaryotes do that => 3 kinds of eukaryotic life cycles
adult
adult
adult
adult