BIOL 103_Fa.24.11.22_CellCycle - Tagged
Page 1: Overview of Fall 2024 Poster Project
Syllabus: Information for rough draft poster due on October 30, worth 5 points.
Account Announcements: emphasis on digital poster info, including rating and submission details.
Assignments: Key components include selecting gene for poster project due September 27 (2 points), and collaborations within various course modules.
Resources: Access to example posters from previous semesters on diseases like Sickle Cell and Cystic Fibrosis, among others.
Page 2: Textbook Readings for November 22
Chapter 17.1 - The Eukaryotic Cell Cycle:
Phases of the cell cycle, growth factor regulation, and checkpoints significance.
Chapter 17.2 - Regulators of Cell Cycle Progression:
Mechanisms of growth factor regulation, DNA replication control, and DNA damage checkpoints.
Chapter 5.1 - DNA Replication:
Proteins/mechanisms at replication forks, mechanisms for accurate replication, and telomerase actions.
Upcoming Reading: Chapter 5.2 focuses on DNA repair mechanisms to be discussed on December 2.
Page 3: Introduction to the Cell Cycle
The Cell Cycle Overview: All cells reproduce by dividing, ensuring each parental cell gives rise to two daughter cells.
Page 4: Interphase and Mitosis Overview
Interphase:
Includes G1, S, and G2 phases.
Chromosomes decondensed, looking morphologically uniform.
Phase Details:
G1 Phase: Gap between mitosis and initiation of DNA replication.
S Phase: DNA replication occurs.
G2 Phase: Continued cell growth, protein synthesis for mitosis, and DNA checking.
Page 5: Mitosis and Cytokinesis
Mitosis:
Most dramatic stage with daughter chromosome separation.
Cytokinesis:
Marks the end of mitosis, as cells divide.
Page 6: Clarification on G1 Phase
G1 Phase Key Points:
Primarily a gap phase, not a direct growth phase.
Overall control of progression through the cell cycle.
Page 7: G1 Restriction Point
Restriction Point:
Controls whether cells enter S phase primarily regulated during G1.
Cells may enter G0 phase without growth factors; they remain metabolically active but non-dividing.
Page 8: Embryonic Cell Cycle Characteristics
Duration Variation: Different cell types have varying cycle phase durations.
Embryonic Mitosis: Lacks a G1 phase, with decreasing cell volume with each cleavage.
Page 9: Yeast Models in Cell Cycle Studies
Cell Types Studied:
Schizosaccharomyces pombe and Saccharomyces cerevisiae as models for cell cycle research.
Page 10: Stem Cell Division
Asymmetric Cell Division in Stem Cells:
Produces 2 daughter cells: one self-renewing stem cell and one rapidly dividing transit-amplifying cell.
After several divisions, cells differentiate, halting further proliferation.
Page 11: Hematopoietic Stem Cells
Source: Blood cells originate from hematopoietic stem cells located in the bone marrow.
Production Rate: Approximately 100 billion blood cells are lost per day in humans.
Page 12: Key Principles of the Eukaryotic Cell Cycle
Cell Division: All cells reproduce via division, leading to two daughter cells.
Symmetric vs. Asymmetric: Division can be equal (symmetric) or unequal (asymmetric).
Genome Integrity: Regulation of growth and DNA replication is crucial for maintaining genome integrity.
Checkpoints: Prevent transition to the next phase until prior phase events are complete.
Page 13: Main Classes of Regulators in Cell Cycle
Classes:
Cyclins: Proteins that regulate the cycle.
CDKs: Cyclin-dependent kinases.
CDCs: Cell division cycle phosphatases.
Regulation Points: Important checkpoints at various phases of the cell cycle.
Page 14: Continued Classes of Regulators
Regulation Details:
G1 has restriction points involving specific cyclin-CDK complexes.
Regulation through external signals.
Page 15: Phosphorylation and Cell Cycle Regulation
Cdk Activation:
Cells are committed to DNA synthesis post-restriction point.
Regulation by growth factors in G1 influences cell cycle progression.
Page 16: Growth Factor Pathway Activation
Growth Factor Regulation:
Activates Ras/Raf/MEK/ERK pathway, stimulating cyclin D synthesis and regulating p27.
Page 17: Rb Protein and E2F
Role of Rb:
Rb binds E2F transcription factors in G0 and early G1, suppressing cell cycle progression until phosphorylated.
Page 18: Rb Mutations Investigation
Questions on the consequences of Rb null mutations and effects of cyclin D silencing on cell division.
Page 19: Reiteration on Growth Factor Regulation in G1
Pathway Activation Details:
Discusses the Ras/Raf/MEK/ERK pathway and its effects.
Page 20: p27 and Cdk2 Regulation
p27 Functions: Inhibits Cdk2/cyclin E during G0 and early G1; involved in cell cycle progression initiation.
Page 21: Cycle Regulatory Components
Class Structure: Identifies G1, S, and G2 checkpoint roles through specific cyclin-CDK relationships.
Page 22: Questions on DNA Synthesis and Origins
Focused questions regarding DNA synthesis origins and Cdk2/cyclin E activation.
Page 23: Continuation of DNA Synthesis Overview
Further elaboration on DNA synthesis origins and regulatory proteins.
Page 24: Eukaryotic Chromosome Replication Initiation
Replication Initiation: Occurs at multiple spots along the chromosome, varying between mammalian and yeast cells.
Page 25: Helicase Role in DNA Unwinding
Helicase Functionality: Catalyzes unwinding of DNA strands using multimeric enzymes associated with eukaryotic cells.
Page 26: Origin Recognition Complex (ORC)
ORC Functions:
Guides recruitment of key proteins like MCM and enables phosphorylation for activation.
Page 27: APC/C Functionality
Ubiquitin Ligase Role: Interacts with multiple proteins, critical for degradation processes.
Page 28: Recap of APC/C Functions
Ubiquitin Explanation: Describes the process and importance of APC/C in cell cycle regulation and protein turnover.
Page 29: DNA Synthesis Queries
Questions focusing on replication origins, synthesis activation, and repair mechanisms.
Page 30: DNA Strands Unwinding
d - Single Stranded DNA Binding: Proteins bind and stabilize the unwound strands during replication.
Page 31: Topoisomerase Functions
Types of Topoisomerases: Roles of Type I and II in creating reversible breaks and managing DNA supercoiling during replication.
Page 32: DNA Polymerase Accessory Functions
Clamp Loading Mechanisms: RFC and PCNA functions in loading the DNA polymerase onto strands for replication.
Page 33: Overview of DNA Polymerases
Roles and Types: Different polymerases involved in DNA synthesis and their specific functions in prokaryotic/eukaryotic cells.
Page 34: DNA Polymerase Laws
Key Principles: Directions of synthesis, initiation requirements, and differences between DNA and RNA polymerases.
Page 35: Leading and Lagging Strand Dynamics
Replication Mechanics: Explains the dosage-dependent and discontinuous replication nature of the lagging strand.
Page 36: RNA Primer Usage
Initiation of Replication: Use of short RNA primers synthesized by primase as a crucial component.
Page 37: Lagging Strand Synthesis Methodology
Okazaki Fragments: Details on removal of RNA primers and joining of fragments through ligase action.
Page 38: Telomere Structure Overview
Telomeres Description: Function and structure of telomeres in eukaryotic chromosomes.
Page 39: Telomerase Functionality
Telomerase Role: Describes how reverse transcriptase regulates telomere length during replication.
Page 40: Telomere Activity Maintenance
Eukaryotic Specifics: Importance of telomerase for maintaining telomere integrity and its role in cellular aging.
Page 41: Telomere Synthesis Process
Detailed Mechanism: Clarifies the telomerase process of extending telomeres and how it interacts with existing strands.
Page 42: Continual Lagging Strand Extension
Primer Use During Extension: Importance of primers in forming newly synthesized fragments upon telomere extension.
Page 43: Telomere Length and Cancer Correlation
Impact of Telomerase Activity: Discusses implications for somatic cells, cellular aging, and links to cancer proliferation.
Page 44: Summary of DNA Synthesis Topics
List of critical questions on synthesis origins and associated mechanisms.
Page 45: Review of Repair Mechanisms
Discussed were different DNA repair mechanisms, notably after damage detection and synthesis errors.
Page 46: Fidelity of Replication
Importance of Fidelity: Highlights the need for accuracy during DNA replication and its mechanisms.
Page 47: Proofreading Mechanisms of DNA Polymerase
Exonuclease Functionality: Role of different polymerases in proofreading newly synthesized DNA strands post-replication.
Page 48: Mismatch Repair System Overview
Key Components: MMR's role in identifying and excising mismatched bases to prevent mutations.
Page 49: Review of Repair Mechanisms (Continued)
Emphasis on multiple mechanisms for damage repair during DNA synthesis, particularly specialized polymerases.
Page 50: UV Damage Repair Mechanisms
Discussed the impact of UV light on DNA and a variety of repair strategies available to the cell.
Page 51: Translesion DNA Synthesis Overview
Overview of translesion synthesis in both prokaryotic and eukaryotic cells, indicating specialized polymerase functions.
Page 52: Resumption of Normal Replication
Describe the continuum post-translesion synthesis leading back to normal replication mechanics.
Page 53: Recapping Damage and Repair Mechanisms
Summary of repair mechanisms and their role during synthesis/governing DNA integrity.
Page 54: DSB Repair Mechanisms
Homology-directed Repair and NHEJ: Distinctions between homology-directed repair and non-homologous end joining mechanisms.
Page 55: Non-Homologous End Joining
Repair Mechanism Details: Outline of the process for DSB repair through ligase actions and additional nucleases.
Page 56: Overview of HDR and NHEJ
Visual Explanation: Diagram representations of the distinct pathways for double-strand break repairs.
Page 57: Understanding Repair Timing
Repair Mechanisms: Evaluation of when certain repair mechanisms are essential during the cell cycle.
Page 58: Role of Checkpoints in DNA Damage
Key Checkpoint Proteins: Role of ATM and ATR kinases in mediating cell cycle arrest upon DNA damage.
Page 59: ATM and ATR Functions
Checkpoint Activation: Mediating DNA repair, cell cycle arrest, and elevating cell apoptosis in response to damage.
Page 60: Cell Cycle Arrest Mechanism Details
Inhibition Mechanism: Chk1 and Chk2 mediating cell cycle arrests by inhibiting critical phosphorylation pathways.
Page 61: p53 Regulation in Arrest Mechanisms
p53's Role: Functionality of p53 in cell cycle arrest through activation and induction of Cdk inhibitors like p21.