Meiosis Division of Sex Cells Meiosis A process
- Slides: 26
Meiosis Division of Sex Cells
Meiosis § A process of reduction division in which the number of chromosomes is cut in half through separation of homologous pairs in a diploid cell. § Diploid – 2 sets of chromosomes § Haploid – 1 set of chromosomes § Homologous – pairs of matching chromosomes that come from each parent
Meiosis
Meiosis Stages § Meiosis involves 2 distinct cell divisions: § Meiosis II
Prophase I § Each chromosome pairs with its corresponding homologous chromosome to form a tetrad. § There are 4 chromosomes in a tetrad. § The pairing of homologous chromosomes is the key to meiosis. § Crossing-over may occur here § Crossing-over is when chromosomes overlap and exchange portions of their DNA
Prophase I
Metaphase I § Spindle fibers attach to the chromosomes § Homologous pairs line up side by side
Metaphase I
Anaphase I § The fibers pull the homologous chromosomes toward opposite sides.
Anaphase I
Telophase I & Cytokinesis § Nuclear membranes form. § The cell separates into 2 cells.
Telophase I
End of Meiosis I § Meiosis I results in two haploid (N) cells. § Each cell has half the number of chromosomes as the original cell.
Prophase II § Chromosomes re-condense and nuclear membrane breaks down again (similar to Prophase of Mitosis)
Prophase II
Metaphase II § The chromosomes line up similar to metaphase in mitosis.
Metaphase II
Anaphase II § Sister chromatids separate and move to opposite sides.
Anaphase II
Telophase II and Cytokinesis § Meiosis II results in 4 GENETICALLY DIFFERENT haploid cells. (gametes)
Telophase II
Gamete Formation § In males, meiosis results in 4 sperm cells (spermatogenesis)
Gamete Formation § In females, meiosis results in 1 egg cell and three polar bodies, which are not used in reproduction. (Oogenesis)
Mitosis vs Meiosis Results in Cells are Occurs in Mitosis 2 Diploid Cells (2 N) Genetically Identical Somatic (Body) Cells Meiosis 4 Haploid Cells (N) Genetically Different Sex Cells
- Sex sex sex
- Sex in the greenhouse
- Xxtesticles
- Sex sex sex
- Sex sex sex
- X linked recessive punnett square
- Sex determination and sex linkage
- Sex determination and sex linkage
- Once a sex offender always a sex offender
- Gametes
- Plant sex cells
- Cells
- Sex cells
- How many chromosomes are in a human’s sex cells?
- Waters view
- Principal cells vs intercalated cells
- Thyroid parafollicular cells
- Somatic cells vs gametes
- Why dna is more stable than rna
- Red blood cells and white blood cells difference
- Prokaryotic cells
- Plant cell vs animal cell venn diagram
- Prokaryotic cell
- Why did robert hooke name cells “cells”?
- Masses of cells form and steal nutrients from healthy cells
- Younger cells cuboidal older cells flattened
- What animals have prokaryotic cells