Unit 5.1 Flashcards
What does meiosis ensure?
It ensures the formation of halpoid gamete cells in sexually producing diploid organisms
What does diploid mean?
It means that there are 2 full sets, or pairs of chromosomes
2n
What does haploid mean?
It means that the cell contains one set of chromosomes
n
Do diploid chromosomes have to be identical?
No, they can differ in shape, size, and even centromere location
What do diploid chromosomes contain in meiosis?
They contain a set of chromosomes from each parent
Where can diploid cells be found in nature?
Somatic cells (skin cells, leaf cells, hypha cells in fungi)
Where can haploid cells be found in nature?
Gametes and sex cells (egg, pollen)
How is a diploid cell formed in sexual reproduction?
By two haploid cells coming together
What does meoisis result in?
It results in daughter cells with half of the chromosome number as the parent cell
What does the diploid parent cell produce at the end of meiosis?
4 haploid daughter cells
How many rounds of division is in meiosis?
There are 2 rounds; meiosis 1, and meiosis 2
What happens in meiosis I?
Prophase I, metaphase I, anaphase I, and telophase I,
What happens in prophase I?
- Nuclear envelope begins to disappear.
- Fibers begin to form.
- DNA coils into visible duplicated (or double) chromosomes made up of sister chromatids
- Double chromosomes pair up based on size, shape, centromere location, and genetic information.
- While paired, chromatids exchange genetic information with chromatids from the other chromosome (nonsister chromatids exchange genetic information by the process of crossing over).
Crossing over happens HERE
What happens in metaphase I?
- Double chromosomes remain in pairs
- Fibers align pairs across the center of the cell
What happens in anaphase I?
- Fibers separate chromosome pairs
- Each double chromosome, from the pair, migrates to opposite sides of the cell
What happens in telophase I?
- Nuclear envelope reappears and establishes two separate nuclei
- Each nucleus contains only one double chromosome from each pair
- Nucleus only contains half of the total information the parent nucleus contained
- Cytokinesis will separate the cell into two daughter cells
- Daughter cells are haploid and genetically different from each other and the parent cell
What happens in metaphase II?
- Nuclear envelope begins to disappear
- Fibers begin to form
What happens in anaphase II?
- Fibers separate sister chromatids
- Chromatids (single chromosomes) migrate to opposite sides of the cell
What happens in telophase II?
- Nuclear envelope reappears and establishes separate nucle
- Each nucleus contains single chromosomes
- Chromosomes will begin to uncoil
- Cytokinesis will separate the two cells into four daughter cells
- Daughter cells are haploid and genetically different from each other and parent cell
What are meiosis and mitosis similar in?
Mitosis and meiosis are similar in the way genetic information is passed to daughter cells.
Both processes involve:
* Nuclear envelope disappearing
* DNA coiling into chromosomes
* Aligning chromosomes in the center of the cell
* Using fibers to separate chromosomes
* Nuclear envelope reappearing
* Chromosomes uncoiling
* Followed by cytokinesis and production of daughter cells
What do meiosis and mitosis differ in?
Mitosis and meiosis differ in the number of resulting cells and the genetic content of the cells.
* Mitosis produces two daughter cells that are genetically identical to the parent cell
* Meiosis produces four haploid daughter cells that are genetically varied from each other and the parent cell
