MA'AM

Cards (15)

  • Cell Cycle
    • The cell cycle is the life cycle of a cell. During this cycle, cell grows and divides.
    • Normal cells, however, move through the cell cycle in a regulated way.
    • They use information about their own internal state and cues from the environment around them to decide whether to proceed with cell division.
    • This regulation makes sure that cells don't divide under unfavorable conditions (for instance, when their DNA is damaged, or when there isn't room for more cells in a tissue or organ).
  • Interphase
    • In interphase, the cell grows and takes in nutrients in preparation for division. Interphase takes up about 90 percent of the cell cycle.
    • It consists of three parts: Gap 1, Synthesis, and Gap 2.
  • A cell moves through a series of phases in an orderly manner. During interphase,

    1. G1
    • involves cell growth and protein synthesis, the
    • Gap 1 (G1) is also known as a growth phase. The cell gets larger and increases its stock of proteins, along with organelles such as the energy-producing mitochondria
  • During interphase,

    2. S phase
    • involves DNA replication and the replication of the centrosome, and
    • Synthesis (S) is the phase in which DNA replicates. During synthesis, the chromosomes replicate so that each chromosome is made up of two sister chromatids. At the end of this phase, there is double the amount of DNA in the cell.
  • During interphase,

    3. G2
    • involves further growth and protein synthesis.
    • Gap 2 (G2) is another growth phase. The cell becomes even larger in order to prepare for mitotic division.
  • Quiescence (Go)
    • , also known as senescence or resting, is a phase in which the cell is not actively dividing.
    • It is also known as Gap 0, or Go.
    • This stage is considered the start of the cell cycle, although it is one that cells can reach and then stop dividing indefinitely, which ends the cell cycle.
    • Spinal chord, Liver, stomach, kidney cells, and neuron are all examples of cells that can reach this stage and remain in it for long periods of time. cell's DNA is damaged.
  • Mitotic Phase
    • The mitotic phase follows interphase.
    • Mitosis - is nuclear division during which duplicated chromosomes are segregated and distributed into daughter nuclei.
    • Usually the cell will divide after mitosis in a process called cytokinesis in which the cytoplasm is divided and two daughter cells are formed.
  • Mitotic Phase
    • Mitosis, or M phase, is when the cell begins to organize its duplicated DNA for separation into two daughter cells.
    • The chromosomes separate so that one of each chromosome goes into each daughter cell.
    • This results in the daughter cells having identical chromosomes to the
  • Mitosis itself is divided into:
    1. prophase,
    2. metaphase
    3. anaphase, and
    4. telophase, which mark various points in the DNA separation process. Mitosis is then followed by a process called cytokinesis, during which the cell separates its nuclei and other organelles in preparation for division and then physically divides into two cells
  • The Cell Cycle and the Checkpoint
    • The cell cycle is controlled at three checkpoints. The integrity of the DNA is assessed at the G1 checkpoint. Proper chromosome duplication is assessed at the G2 checkpoint. Attachment of each kinetochore to a spindle fiber is assessed at the M checkpoint
  • Cell cycle checkpoints
    • A checkpoint is a stage in the eukaryotic cell cycle at which the cell examines internal and external cues and "decides" whether or not to move forward with division. There are a number of checkpoints, but the three most important ones are
  • Cell cycle checkpoints
    1. Cell Growth Checkpoint
    2. DNA Synthesis Checkpoint
    3. Mitosis Checkpoint
  • Cell cycle checkpoints
    1. Cell Growth Checkpoint
    • Occurs toward the end of growth phase 1 (G1) .
    • Checks whether the cell is big enough and has made the proper proteins for synthesis phase
    • If not, the cell goes through a resting period (GO) until it is ready to divide
  • Cell cycle checkpoints
    • 2. DNA Synthesis Checkpoint
    • Occurs during the synthesis phase (S)
    • Checks whether DNA has been replicated correctly.
    • If so, the cell continues on to mitosis (M)
  • Cell cycle checkpoints
    • 3. Mitosis Checkpoint
    • Occurs during the mitosis phase (M)