Meiosis Flashcards
Can you describe the process of meiosis?
Meiosis 1
2n to n diploid to haploid
Homologous chromosomes pair up into bivalents
Line up and crossing over occurs
Independent segregation
One from each pair enters each daughter cell
Meiosis 2
Sister chromatids separated at centromere
Each one from a chromosome enters into each daughter cell.
Why is meiosis necessary? What types of cells does meiosis result in?
Produced 4 Genetically diverse gametes
Converts diploid cells into haploid gametes
Occurs only in gonad tissues (tissues, ovaries)
How does meiosis create genetic variation?
Crossing over at chiasmata- prophase 1
Homologous pair twist around each other chromatids break and rejoin at the same loci on sister chromosomes, producing recombinant alleles on recombinant chromatids.
Independent segregation - metaphase 1 and 2
Equal random chance of maternal/paternal chromosomes moving to either pole of the cell.
Random mating/ random fertilisation
How would you calculate the possible chromosome combinations following meiosis? And the number of possible chromosome combinations produced from the fertilisation of two gametes?
2^n for chromosome combination
2^23 = 8388608
Can you explain the different outcome of mitosis and meiosis?
Mitosis: produced 2 genetically identical daughter cells
Meiosis: 4 genetically different gametes
