HBio Cell Cycle Practice

• G1 phase


  The first gap, or growth phase, of the cell cycle, consisting of the portion of interphase before DNA synthesis begins.
• G2 phase


  The second growth phase of the cell cycle, consisting of the portion of interphase after DNA synthesis occurs.
• S phase


  The synthesis phase of the cell cycle; the portion of interphase during which DNA is replicated.
• interphase


  Cell grows, performs its normal functions, and prepares for division; consists of G1, S, and G2 phases
• M phase


  The phase of the cell cycle that includes mitosis and cytokinesis.
• mitosis


  part of eukaryotic cell division during which the cell nucleus divides
• G0 phase


  A nondividing state occupied by cells that have left the cell cycle, sometimes reversibly.
• CDK cyclin


  are the chemicals by which a cell determines if a cell is ready to pass a checkpoint
• G1 checkpoint

  checks to see if cell size is adequate; chromosomes replication is successfully completed and checks for DNA errors
• G2 checkpoint


  asses if DNA replication has occured, go ahead signal triggers mitosis
• apoptosis


  programmed cell death
• M checkpoint


  Spindle assembly checkpoint. Mitosis will not continue if chromosomes are not properly aligned.
• p53


  If DNA is damaged, p53 stops the progression to S phase by inhibiting the G1 CDK-cyclin complex
• Proto-oncogenes


  • Genes that encode cell cycle regulators, encode stimulating proteins
• Mutations in regulatory genes can result in cancer
• Uncontrolled and unregulated cell division can result in cancer
• Cell division


  Important component of living organisms, allows growth, development, repair, and replacement of damaged tissues
• Tumor suppressor genes


  • Genes that encode inhibitory proteins, slow down cell cycle
• APC/C

  Anaphase-promoting complex/cyclostome, encourages anaphase by breaking down proteins in centromere, allows chromatids to separate and move to opposite sides of the cell
• Rb


  Retinoblastoma protein, regulates cells entering the S phase by preventing entry in the absence of signals from growth factors
• Cyclin-dependent kinases (CDKs)

  Cell cycle regulators that add a phosphate to other proteins to activate or inhibit their function
• Mutation in a tumor suppressor gene would lead to uncontrolled cell division
• Mutation in a proto-oncogene would increase gene stimulation, essentially "having their foot on the accelerator"
• Mutation in proto-oncogenes

  Results in a GAIN of function, requires ONE allele to be mutated, considered DOMINANT
• Mutation in tumor suppressor genes

  Results in a LOSS of function, requires TWO alleles to be mutated, considered RECESSIVE
• G1 phase (Gap 1) - A period of growth and preparation for S phase
• The cell cycle is the series of events that occur within a eukaryotic cell from its birth to division.
• S phase (Synthesis) - DNA replication occurs
• G2 phase (Gap 2) - Preparing for mitosis
• Mitotic phase (Mitosis) - Chromosomes are separated into two daughter nuclei
• Interphase - The longest stage of the cell cycle where DNA replication occurs.