Chapter 2: Mitosis and Meiosis Flashcards
Are somatic cells haploid or diploid?
Diploid. They all contain the same number of chromosomes as the parent cell.
What does “homologous chromosomes” mean?
The pair of chromosomes in somatic cells. Each member of the pair is a homologous chromosome.
This number is one half of the diploid number, and these chromosomes as a set make up the genome.
Haploid number.
During this phase in the cell cycle, DNA is being synthesized in preparation for mitosis.
S phase
This phase of the cell cycle comes before S phase. No DNA synthesis is occurring during this phase.
G1 phase
This phase of the cell cycle comes after S phase right before mitosis. No DNA synthesis is occurring during this phase.
G2 phase
During this phase of the cell cycle, a cell decides to become non-dividing and stops going through the cell cycle.
G0 phase
During this stage of mitosis, the DNA condenses into chromosomes and the nuclear membrane starts to break down.
Prophase
During this stage of mitosis, the chromosomes are pulled by kinetochore microtubules to the center of the metaphase plate, where their centromeres are lined up.
Metaphase
During this stage of mitosis, the centromeres let go and the sister chromatids are pulled to opposite sides of the cell by microtubules.
Anaphase
During this stage of mitosis, each of the two sister chromatids is present in the cell until the cell splits down the middle (cytokinesis).
Telophase
In meiosis, genetic material passed on to daughter cells (gametes) is cut in half because you end up with one _______ set of chromosomes.
Haploid
During this stage of meiosis, DNA condenses into chromosomes and the nuclear envelope breaks down. Recombination is occurring.
Prophase I
During this stage of meiosis, the homologous chromosomes line up in at the center of the cell. Recombination is occurring.
Metaphase I
During this stage of meiosis, the chromosomes move to opposite sides of the cell. Each daughter cell has 23 chromosomes.
Anaphase I
During this stage of meiosis, the parent cells split into two daughter cells, each with the 23 chromosomes.
Telophase I
During this stage of meiosis, the spindles begin to form in the daughter cells.
Prophase II
During this phase of meiosis, the chromosomes line up along the middle of the cell.
Metaphase II
During this phase of meiosis, the chromosomes are pulled apart into their sister chromatids to opposite sides of the cell.
Anaphase II
During this phase of meiosis, each of the two daughter cells divides again.
Telophase II
Meiosis results in ________ (haploid/diploid) gametes.
4, haploid
In males, gamete formation results in ___ sperms.
four
In females, gamete formation results in ___ egg(s).
one
How do you end up with one egg for females?
The primary oocyte divides. One daughter cell is the secondary oocyte and gets more cytoplasm. The other is the first polar body. Then the secondary oocyte divides, resulting in the ootid and the second polar body, and the ootid becomes the ovum that’s released during ovulation.
When does DNA replication occur for the eggs –before ovulation or when it’s time to ovulate?
Before, during embryonic development. The primary oocyte starts on meiosis I, but arrests after prophase (replication of DNA is completed here). Years later, when it’s time to start ovulating, one primary oocyte per ovulation gets to continue with meiosis and go to completion, making an ovum and releasing the egg.
