Cell Cycle, Mitosis, & Meiosis Flashcards
(29 cards)
What is the cell cycle?
It describes the cell’s life as it goes through phases of division.
What are the three parts that the cell cycle can be divided into?
Resting Phase (G0)
Interphase (G1, S, G2)
Cell Division (P,M,A,T)
What is the Gap 0 (G0) phase?
It is the resting phase. The cell does not participate in cell division during this phase.
What is mitosis?
Asexual reproduction of cells.
What is Interphase?
It is the phase when a cell prepares for divison. Roughly takes up about 90% of the time in the cell cycle. This is where growth and DNA Replication occurs.
What happens during the Gap 1 (G1), Synthesis (S), and Gap 2 (G2) phase?
G1 = growth
S = DNA replication
G2 = more growth
What happens in the G1 checkpoint (restriction point)?
At this checkpoint is when a cell commits to division. The presence of DNA damage or other external factors can cause a cell to fail this checkpoint and not divide.
What happens in the G2 checkpoint?
This checkpoint takes place before cell division and checks for DNA damage after DNA replication. If damage is detected, it “pauses” cell division until the damage is repaired.
What happens in Mitosis?
Cell division.
What are the four stages of Mitosis?
Prophase
Metaphase
Anaphase
Telophase + cytokinesis
What happens in Prophase?
The cell is prepared to go through mitosis. It involves condensing the DNA such that distinct chromosomes become visible as sister chromatids. The nuclear envelope and nucleolus disappear and the mitotic spindle and kinetochore forms.
What happens in Metaphase?
Chromosomes line up at the middle of the cell along the imaginary line, called the metaphase plate. Also has the final checkpoint. The cell checks to make sure that the kinetochores are attached properly to the microtubules of the mitotic spindle. This prevents improper separation which can lead to nondisjunction.
What happens in Anaphase?
Sister chromatids are separated and pulled to opposite sides of the cell by shortening the microtubules.
What happens in Telophase + cytokinesis?
The new nuclear envelope and nucleolus appears around each set of chromosomes. Finally, cytokinesis occurs and separates the cell into two daughter cells.
What is Meiosis?
It is the form of cell division essential for sexual reproduction and takes place in germ cells (sex cells)
What is spermatogenesis?
How sperm cells form
What is oogenesis?
How eggs are formed
What is a kinetochore?
It is on the centromere and the site where the microtubule fibers that extend from the centrosome and from the mitotic spindle attach to pull sister chromatid apart in anaphase.
What does meiosis result in?
It results in four haploid (n) daughter cells while mitosis results in two diploid (2n) cells.
Are meiosis daughter cells identical like mitosis daughter cells are?
No, the daughter cells that result from meiosis are not identical unlike the two daughter cells from mitosis. These non identical daughter cells are called gametes.
What is a zygote?
The first diploid cell that forms when two haploid gametes fuse and create first diploid cell.
How many round of cell division does meiosis go through?
2 and some stages are different than mitosis
What happens in Meiosis I ?
The first round of division and results in the formation of two haploid daughter cells that contain duplicate sister chromatids.
What happens in Prophase I ?
Homologous chromosomes (1 from mom, 1 from dad) pair up with each other in a process called synapsis and form tetrads. While paired up, homologous chromosomes may exchange genetic information in a process known as crossing over.
