10.3 Flashcards
What is meiosis?
The process where gametes are made through cell division.
What are homologous chromosomes?
Chromosomes that are similar, but not exact replicas of each other.
What are sister chromatids?
Chromatids with identical DNA.
What is fertilization?
The process of sexual reproduction.
What is asexual reproduction?
An organism copying itself to reproduce.
What is a gamete?
A haploid cell used in sexual reproduction.
What is a somatic cell?
A diploid body cell that does a function.
What is a haploid?
A cell with only one copy of a sister chromatid, has half the chromatids as a diploid.
What is a diploid?
A cell with two copies of a sister chromatid, making a chromosome, has twice as many chromatids as a haploid.
What is a tetrad?
Two homologous chromosomes lined up next to each other in the first stage of meiosis.
What is a synapsis?
The pairing of two homologous chromosomes during prophase I.
What is crossing over?
One of the sister chromatids in a tetrad of homologous chromosomes will trade its DNA with the chromatid next to it, in a separate chromosome.
What is independent assortment?
The random pattern of where tetrads line up in metaphase I.
What is the order of events in meiosis?
Prophase I, where the chromosomes form tetrads and cross over, metaphase I, where tetrads are lined up in the center of the cell, anaphase I, where the tetrads are pulled apart and chromosomes are dragged to opposite ends of the cell, telophase I/cytokinesis I, where the cell splits into two daughter cells, prophase II, where daughter cells are prepared to split again, metaphase II, where sister chromatids are lined up in the center of the cell as chromosomes, anaphase II, where sister chromatids are pulled apart from each other and dragged to opposite ends of the cell, telophase II/cytokinesis II, where the two daughter cells further split into four haploid daughter cells.
When is the chromosome number reduced by half?
Cytokinesis I.
What are the sources of genetic variation?
Crossing over, where DNA is randomly switched between homologous chromosomes, and independent assortment, where the random pattern of which sides of the cell the chromosomes go during metaphase I changes what DNA will be in the daughter cells.
What are some similarities and differences between mitosis and meiosis?
Both include parent cells splitting apart into two separate cells, mitosis ends with two diploid cells, meiosis ends with four haploid cells, meiosis has crossing over for genetic variation, the two daughter cells of mitosis are exact copies of the parent cell, while the four daughter cells of meiosis are extremely varied and different from each other, and especially different from the parent cell.
What are some similarities and differences between sexual and asexual reproduction?
Sexual and asexual reproduction both end with the new organism containing DNA from the parent(s). Sexual reproduction has more genetic variation, and it requires two members of a species, asexual reproduction has little to no genetic variation, the only bit coming from mutations in copying DNA, and it only requires one member of a species.
