One parent reproduces genetically identical offspring by mitosis
Asexual Reproduction
Two parents give rise to offspring that have unique combinations of genes inherited from the two parents.
Sexual Reproduction
Where does asexual reproduction occur?
Mitotic Division
Where does sexual reproduction occur?
Meiosis
One set of chromosomes is inherited from each parent during sexual reproduction in what type of organisms?
Diploid
Have 2 sets of 23 chromosomes for a total of 46.
Humans
Have a homologous pair of X chromosomes (XX)
Females
Have one X chromosome and one Y chromosome (XY)
Males
22 pairs of chromosomes that do not determine sex.
Autosomes
Splits homologus chromosomes
1st cell division of meiosis
Splits sister chromatids
2nd cell division of meiosis
Produces haploid gametes from diploid mother cells
Meiosis
Starts as diploid mother cells and ends as diploid mother cells
Mitosis
homologous chromosomes separate resulting in two haploid daughter cells with replicated chromosomes.
1st cell division of meiosis 1
Sister chromatids separate resulting in four haploid daughter cells with unreplicated chromosomes.
2nd cell division of meiosis 2
Prophase 1
Metaphase 1
Anaphase 1
Telophase 1
Occurs in meiosis 1
Prophase 2
Metaphase 2
Anaphase 2
Telophase 2
Occurs in meiosis 2
How many chromosome does a diploid cell have?
6 chromosomes
How many pairs of chromosomes does a diploid cell have?
3 pairs
How many chromosomes does a haploid cell have?
3 chromosomes
Homologus pairs are joined together side by side to form what type of structure?
Tetrads
Tetrads form in what phase?
Prophase 1 of meiosis 1
Tetrads move to the middle of the cell in what phase?
Metaphase 1 of meiosis 1
tetrads are attached to each side of the cell by spindle fibers in what phase?
Anaphase 1 of meiosis 1
breaks form and physically interacts with each other through crossing over.
Tetrads
Two new cells are formed containing 3 chromosomes in each
Telophase 1
Has one round and ends with 2 diploid daughter cells
Mitosis
Haploid cells do not occur during what cell cycle?
Mitosis
Has two rounds and ends with 4 haploid daughter cells
Meiosis
DNA replication
Both mitosis and meiosis
one cell division
mitosis
two cell divisions
meiosis
Synapsis and crossing over
only occurs in meiosis
Daughter cells, genetic composition in mitosis?
Two diploid, identical to parent cell
Daughter cells, genetic composition in meiosis?
four haploid, different from parent cell and eachother
Role in multicellular body of mitosis?
Produces cells for growth and tissue repair
Role in multicellular body of meiosis?
Produces gametes
What three mechanisms contribute to genetic variation?
- Independent assortment of chromosomes
- Crossing over
- Random Fertilization