Lecture Notes: Cell Cycle and Cancer

Introduction

• Thought Experiment: Wonder what skin cells are doing.
• Cell Theory: All living things are made of cells. Cells work together in tissues, organs, and systems.
• Cell Specialization: Includes skin cells, stomach cells, muscle cells.

Cell Cycle

• Purpose: Regulate cell function and growth.
• Growth in Multicellular Organisms: Occurs by cell division (not by cells getting larger).
• Mitosis and Cytokinesis: Processes for cell division to create new body cells.

Cancer

• Definition: Uncontrolled cell division leading to growth of cancer cells.
• Characteristics of Cancer Cells:
  • Unregulated division.
  • Potential lack of communication with healthy cells.
  • Inability to perform normal functions or anchor properly.
  • Can divert nutrients by secreting own growth hormones.
• Causes: Genetic links, exposure to toxins, radiation, UV light.
• Treatment: Includes radiation and chemotherapy targeting frequent cell division.

Cell Cycle Phases

• Interphase: Cell grows, replicates DNA, performs functions.
• M Phase: Includes mitosis and cytokinesis.
• Phase Duration: Most time spent in interphase.
• Checkpoint Control:
  • G1: Checks growth, DNA integrity, resources.
  • S: DNA replication phase.
  • G2: Prepares for mitosis, checks DNA replication and growth.
  • M: Ensures chromosomes are correctly aligned and attached to spindle.

Regulatory Proteins

• Positive Regulators: Cyclin and CDK promote cycle progression.
• Negative Regulators: Proteins like p53 can initiate apoptosis (cell self-destruction).

G0 Phase

• Definition: Resting phase where cells perform functions but do not prepare to divide.
• Examples: Neurons often remain in G0, affecting healing after injuries.

Conclusion

• Encouragement: Stay curious and explore topics like cell cycle regulation and cancer treatments further.