Meiosis + Fertilization Flashcards
Sexual Reproduction
when two organisms come together to make offspring through fertilization
Gametes
sex cells (egg, sperm)
Homologous Chromosomes
chromosomes that are the same size and shape and have the same genes
Diploid
a cell with 2 sets of chromosomes (2n)
Haploid
a cell with one set of chromosomes (n)
Zygote
a cell that is made from fertilization (when the egg and sperm meet; a fertilized egg)
Tetrad
a structure that consists of homologous chromosomes
Crossing Over
the exchange of genes between the chromosomes in a tetrad
The process of meiosis helps ____ diversity
genetic
Purpose of Meiosis
to create gametes with half the number of chromosomes
Meiosis I
homologous chromosomes are split
Purpose of Meiosis I
to pair up homologous chromosomes; cross-over; genetic diversity; split homologous chromosomes
Stages in Meiosis I
Prophase I, Metaphase I, Anaphase I, Telophase I
End result of Meiosis I
2 cells with half the number of chromosomes as the parent
Meiosis II
to split sister chromatids and make gametes
Stages in meiosis II
Prophase II, Metaphase II, Anaphase II, Telophase II
End result of Meiosis II
4 non-identical cells with half the number of chromosomes at the parent
How many divisions happen during mitosis?
1
How many divisions happen during meiosis?
2
Fertilization
the process where an egg and a sperm cell meet to make a zygote
Zygote
a cell created from fertilization; a fertilized egg
a diploid cell made from two haploid cells meeting
Cycle of Life
Adults –> Meiosis –> Egg and Sperm –> Fertilization –> Zygote –> Mitosis –> makes an embryo —> Mitosis into an adult
Synapsis
the pairing of homologous chromosomes and cross-over
Somatic Cell
a cell that is any cell of a living organism that is not a reproductive cell
What cells divide during meiosis?
sex organ cells (ovaries, testes)
Once the chromosomes have formed a pair, what are they called?
tetrad
Recombinant Chromatids
paired chromosomes that have already exchanged the same type of gene in their non-sister chromatids
After meiosis how many copies of chromosomes do each cell have?
one copy of half of the genetic information
What type of cells does meiosis result in?
gametes
Why does crossing-over rarely occur in mitosis, unlike meiosis?
tetrads rarelt form in mitosis
