Updated: 1/15/2018

Cell Cycle

0%
Topic
Review Topic
0
0
N/A
N/A
Questions
1 1
0
0
0%
0%
Videos
2 2
Overview 
  •  Stages
    • interphase
      • G1
        • purpose
          • cellular growth to prepare for DNA replication
            • synthesis of replication proteins, cyclin D
          • thymidine dimer repair
        • variable duration
        • can exit G1 and enter G0
        • chemotherapeutic agents that target G0
          • cisplatin
          • nitrosoureas
          • antitumor antibiotics
          • alkylating agents
      • S
        • purpose
          • DNA replication
            • cell is 2N before S
            • cell is 4N after S
          • DNA proofreading
          • mismatch repair
        • constant duration
        • chemotherapeutic agents that target this stage 
          • etoposide
          • 6-mercaptopurine
          • 6-thioguanine
          • methotrexate
          • cytarabine
          • hydroxyurea
      • G2
        • purpose
          • cellular growth to prepare for cell division
          • mismatch repair (less active than in S phase)
        • variable duration
        • chemotherapeutic agents that target this stage
          • bleomycin
    • mitosis (M)
      • steps
        • prophase
        • metaphase
        • anaphase
        • telophase
      • chemotherapeutic agents that target this stage
        • vinblastine
        • vincristine
        • paclitaxel
          • all drugs that affect microtubules
  •  Regulation
    • control transitions between phases of cell cycle
      • G1 checkpoint
        • at transition from G1 to S
        • most important checkpoint
    • cyclins/cyclin-dependent kinases
      • cyclin D 
        • produced during G1
        • complex with Cdk4 (cyclin dependent kinase) at sufficient concentration
        • signal to enter S phase
    • tumor suppressors
      • requires mutation in both copies before neoplasia occurs
        • as opposed to oncogenes which require just one mutation
      • Rb
        • prevents cell from entering S phase
        • binds E2F to block its function as a transcription factor
        • named for retinoblastoma
      • P53
        • prevents cell from entering S phase
        • leads to inhibition of kinase activity of Cdk4 via p21
        • can induce apoptosis if cell damage is severe
          • via the BAX gene (proapoptotic)
            • inhibits BCL2 antiapoptosis gene
            • stimulates release of cytochrome c from mitochondria
  • Cell types
    • permanent
      • enter G0 and cannot leave
        • e.g. neurons, skeletal, cardiac muscle, RBCs
    • stable (quiescent)
      • enter G0 and can leave when given appropriate stimulus
        • e.g. hepatocytes, lymphocytes
    • labile
      • never go to G0
      • constant division with a condensed G1
        • e.g. bone marrow, skin, gut epithelium
 

Please rate topic.

Average 4.8 of 20 Ratings

Questions (1)
Question locked
Sorry, this question is for
PEAK Premium Subscribers only
Upgrade to PEAK
VIDEOS (2)
Topic COMMENTS (22)
Private Note