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22 terms

Meiosis and Sexual Life Cycles

Explain in general terms how traits are inherited from parents to offspring.
Crossing over between non-sister chromatids during meisosis creates a gamete with certain traits that have been inherited by the parent and this gamete combines with another gamete from the other parent to create a diploid zygote that becomes the offspring
Distinguish between asexual and sexual reproduction.
Asexual: Identical, reproduction without meiosis Sexual: Two sets of DNA from two haploid cells (gamete), crossing over occurs, reproduction through meiosis
Distinguish between somatic cell and gamete
Gamete: Haploid reproductive cell, unite during sexual reproduction to produce diploid zygote Somatic: Any cell that isnt the gametes
Distinguish between autosome and sex chromosome
Autosome: A chromosome that is not directly involved in determining sex; not a sex chromosome
Explain how haploid and diploid cells differ from each other
Haploid: A cell containing only 1 set of chromosomes Diploid: A cell containing two sets of chromosomes
Which cells in the human body are diploid and which are haploid.
Somatic cells are diploid, gametes are haploid
Explain why fertilization and meiosis must alternate in all sexual life cycles.
Distinguish between the three life cycle patterns characteristic of eukaryotes, and name one organism that displays each pattern.
The production of a genetically different cell - a modified type of cell - that reduces the number of sets of chromosomes from 2 to 1 in gametes.
Prophase I
Metaphase I
Anaphase I
Telophase I and Cytokinesis
Prophase II
Metaphase II
Anaphase II
Telophase II and Cytokinesis
Recognize the phases of meiosis from diagrams or micrographs.
Describe the process of synapsis during prophase I and explain how genetic recombination occurs.
replicated homologs pair up and become physically connected in a synaptonemal complex. At this stage genetic recombination occurs when alleles of the chromosomes are exchanged, pull apart but are still connected at places where synapsis has occurred (chiasmata)
Describe three events that occur during Meiosis I but not during Mitosis
1. Crossing Over and synapsis 2.Formation of homologous pairs on the metaphase plate 3. Separation of homologous pairs
Explain how independent assortment, crossing over, and random fertilization contribute to genetic variation in sexually reproducing organisms.
Crossing Over - genes alleles are swapped, allowing for genetic diversity of the gametes formed Independent Assortment
Explain why heritable variation was crucial to Darwin's theory of evolution
new combination of genes --> more possibilities foir traits for offspring --> more chance to find correct traits for environmental success