AP Biology Lecture Notes

Introduction

• Lecture focuses on cell communication and the cell cycle.
• Resources are available for review, including daily questions, a review guide, and quizzes.
• Today's agenda includes:
  • Overview of cell communication
  • Discussion of the cell cycle
  • Practice questions
  • Q&A session

Resources for Students

• Daily review questions on Instagram.
• Live streams on weekends.
• 374-page review guide with questions and explanations.
• FRQ videos covering 2013-2023.
• 120+ quizzes and games for review.
• All resources available at apopenguin.weebly.com.

Cell Communication

• Signal Transduction Pathway:
  1. Reception: Signaling molecule (ligand) binds to a receptor causing a shape change.
     • Example receptors: G protein-coupled receptors, ligand-gated ion channels, tyrosine kinase receptors.
  2. Transduction: Cascade of molecular interactions relaying signals.
     • Uses phosphorylation cascades and secondary messengers (e.g., calcium, cyclic AMP).
  3. Response: Leads to cellular responses like growth, secretion, gene expression changes, or apoptosis.

Types of Ligands

• Steroid Hormones:
  • Non-polar, bind to intracellular receptors (e.g., testosterone, estrogen).
• Protein Hormones:
  • Polar, bind to extracellular receptors (e.g., insulin).

Recent Exam Question Examples

• Signal Pathways Examples: 2013, 2021, 2018 Exams
  • Understanding the roles of inhibitors and signal pathway components.

The Cell Cycle

• Phases:
  • Interphase (G1, S, G2): Cell growth, DNA replication.
  • Mitotic Phase (Mitosis, Cytokinesis): Division of the nucleus and cytoplasm.

Specific Phases

• G1 Phase:
  • Organelles duplicate, protein and RNA synthesis.
• S Phase:
  • DNA replication.
• G2 Phase:
  • Further cell growth, final preparations for mitosis.
• Mitosis (Mitosis Dance):
  • Prophase: Chromatin condenses.
  • Metaphase: Chromosomes align on metaphase plate.
  • Anaphase: Sister chromatids are pulled apart.
  • Telophase: Formation of two new nuclei.
  • Cytokinesis: Division of cytoplasm.

Regulation of the Cell Cycle

• Checkpoints:
  • G1 Checkpoint: Determines if cell is ready to divide.
  • G2 Checkpoint: Checks DNA replication and repair.
  • M Checkpoint: Ensures sister chromatids are properly attached.
• Role of p53 and Tumor Suppressors:
  • p53 halts the cell cycle for DNA repair.
  • Oncogenes and tumor suppressor gene functions.

Practice Questions

• Discusses specific examples from past exams and how to interpret and respond to various biology questions.

Conclusion

• Overview of available resources and encouragement for further engagement and review.