Unit 4: Topic 6 - Cell Cycle Flashcards
What are the two highly regulated processes that eukaryotic cells undergo to divide and transmit genetic information?
The two processes is mitosis and interphase. Mitosis is the process by which cells divide, and interphase is when the cell is at a resting state and is not undergoing mitosis. There are multiple stages within interphase.
What is the cell cycle?
The cell cycle is a highly regulated series of events for the growth and reproduction of cells. The cell cycle consists of sequential stages of interphase (G1, S, G2), mitosis, and cytokinesis.
What occurs in G1 phase of interphase?
The cell may spend a long time in G1 growing and carrying out its specialized functions. The cells get bigger in size and make proteins and organelles needed for normal functions of DNA synthesis. In this stage, proteins and RNAs are synthesized, and more especially the centromere and other components of the centrosomes are made.
What occurs in the S phase of interphase?
The cell replicates its DNA in the S phase (S for synthesis) in order to prepare for cell division.
NOTE: The DNA synthesized has not yet been condensed into chromosomes yet.
What occurs in the G2 phase of interphase?
G2 is the second growth phase, where the nuclear envelope envelopes the nucleus. Here, the cell makes preparations for mitosis—for example, by synthesizing components of the microtubules that will move the segregating chromosomes to opposite ends of the dividing cell.
What is the G0 phase of the cell cycle?
The G0 phase is a form of the resting state, or quiescence, in which cells reside until they receive appropriate signals - for example, from growth factors - stimulating them to re-enter and progress through the cell cycle. Cells that are not in interphase or mitosis is in G0. During the G0 phase, the cell performs its regular basic cellular functions.
What is mitosis?
Mitosis is a process of nuclear division that occurs when a parent cell divides to produce two identical daughter cells. It typically occurs with somatic (body) cells. Mitosis ensures the transfer of a complete genome from a parent cell to its daughter cells.
What are the roles of mitosis?
Mitosis plays a role in growth, tissue repair, and asexual reproduction.
What are the sequential steps of mitosis?
Prophase –> prometaphase –> metaphase –> anaphase –> telophase
What occurs in prophase of mitosis?
Prophase is the first phase of mitosis, the process that separates the duplicated genetic material carried in the nucleus of a parent cell into two identical daughter cells. During prophase, the nucleolus disappears and the complex of DNA and proteins contained in the nucleus, known as chromatin, condenses.
Three structures appear during prophase and contribute to the orderly segregation of the replicated DNA: the condensed chromosomes, the reoriented centrosomes, and the spindle.
What occurs in prometaphase of mitosis?
In prometaphase, kinetochores appear at the centromeres and mitotic spindle microtubules attach to kinetochores
What occurs in metaphase of mitosis?
In metaphase, chromosomes are lined up in the center/midline of the cell (the equatorial position) and each sister chromatid is attached to a spindle fiber.
THINK: Metaphase for Middle
What occurs in anaphase of mitosis?
In anaphase, sister chromatids (now called chromosomes) separate, and the daughter chromosomes move away from each other toward opposite poles.
THINK: Anaphase for Apart
What occurs in telophase of mitosis?
Telophase occurs after the chromosomes have separated and is the last phase of mitosis. During this step, a nuclear envelope forms around each set of new chromosomes, nucleoli appear, and the chromosomes become less compact. The spindle also disappears at this stage. As a result, there are two new nuclei in a single cell.
What occurs in cytokinesis of the cell cycle?
The cytoplasm divides to form the two new daughter cells, each surrounded by a cell membrane and a cell wall (in organisms that have one).
