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Page 1: Overview of Unit 5

• Image Credits: ©Dimarion/Shutterstock

• Focus: Cells: Stability and Change

• Lesson Overview:

  • Lesson 1: The Cell Cycle

  • Lesson 2: Mitosis and Differentiation

  • Additional topics include:

    • Thing Explainer: Tiny Bags of Water You’re Made of

    • Unit Connections

    • Unit Review

    • Unit Performance Task

Page 2: Unit Project

• Unit Project: Cauliflower Cloning

  • Driving Question: How does the plant make new cells and structures?

  • Activity: Culture a cauliflower plant from a small cutting.

  • Questions to explore:

    1. How do organisms balance growth and division of cells?

    2. How do organisms replace lost or damaged cells?

    3. Do all cells grow and divide in the same way?

    4. How do multicellular organisms develop from a single cell?

• Image Credits: ©SCIMAT/Science Source

• Skin cells are easily shed, leading to dust accumulation.

Page 3: From Single Cell to Multicellularity

• Development of a Frog:

  • Stages: Begins as a single cell that divides repeatedly.

  • All cells come from existing cells.

  • Asexual vs. Sexual reproduction:

    • Asexual: Organisms create genetically identical clones.

    • Sexual: Involves a fertilized egg from sperm and egg fusion.

  • Predictive Inquiry: Why aren't all organisms unicellular?

Page 4: The Cell Cycle Overview

• Living systems exhibit cycles of stability and change, akin to environmental changes.

• Cell diversity in growth and division phases:

  • Cell Cycle: Regular pattern of growth, DNA duplication, and cell division.

  • Interphase: Resting phase (includes G1, S, G2); Mitosis: Dividing phase.

  • Cytokinesis: Final step after mitosis.

Page 5: Checkpoints in the Cell Cycle

• Checkpoints monitor cell progress through the cycle:

  • G1 Checkpoint: Ensures DNA is undamaged; signals for division.

  • G2 Checkpoint: Checks DNA replication and cell size.

• Rates of Cell Division vary:

  • More frequent in embryos/children vs. adults.

• Some cells enter G0 stage if division is infrequent.

Page 6: Factors Affecting Cell Growth

• Cell Size:

  • Expressed as surface area-to-volume ratio.

  • Growth limits tied to effective material transport across the membrane.

• Example Problem: Calculate surface area and volume similarity.

Page 7: Cell Size and Homeostasis

• Oxygen and nutrients cross the cell membrane; inadequate surface area affects homeostasis.

• Cell cycle regulation: internal factors (molecules) and external signals (growth factors).

  • Internal: Kinases and Cyclins help guide cell cycle transitions.

Page 8: Apoptosis and Cancer

• Apoptosis:

  • Programmed cell death crucial for development and harmful cells.

• Cancer originates from disrupted cell cycle regulation leading to uncontrolled cell division.

Page 9: A Brief History of Cell Theory

• Robert Hooke observed cells in cork under a microscope, laying foundation for cell theory.

• Cell theory states:

  1. All organisms are made of cells.

  2. All existing cells arise from other living cells.

Page 10: Advancements in Cell Theory

• Timeline of cell theory advancements highlighting significant figures such as Hooke, Schleiden, Schwann, and Virchow.

Page 11: Experimental Models for Cell Size

• Investigation of diffusion rates in model cells illustrates impact on maintaining homeostasis.

Page 12: Surface Area and Volume in Cells

• Experimental calculations demonstrating surface area-to-volume ratios impact diffusion and cellular functions.

Page 13: Lesson Self-Check

• Review of key concepts regarding cell cycles and division, cell functionality, and external/internal regulation factors.

Page 14: Checkpoints Assessment

• Practical questions to assess understanding of cell cycle principles and checkpoints.

Page 15: HeLa Cells and Immortality

• Discussion of HeLa cells and their unique property of indefinite division.

Page 16: Chromosome Structure

• Explanation of chromosomal changes as cells enter mitosis.

  • Concepts of DNA structure, organization, and preparation for division.

Page 17: DNA Replication and Mitosis

• Detailed overview of replicated chromosomes.

  • Structures like sister chromatids and their significance during cell division.

Page 18: Mitosis Phases

• Distinct phases of mitosis:

  • Prophase, Metaphase, Anaphase, Telophase.

  • Functions and events of each phase leading to cytokinesis.

Page 19: Detailed Mitosis Process

• In-depth analysis of mechanisms ensuring DNA uniform distribution to daughter cells.

Page 20: Asexual and Sexual Reproduction

• Distinction between asexual (rapid, identical offspring) and sexual reproduction (genetic diversity).

• Binary fission in prokaryotes explained.

Page 21: Mitotic Reproduction Forms

• Examples of mitotic reproduction, including budding and fragmentation in various organisms.

Page 22: Cell Differentiation

• Overview of differentiation in multicellular organisms, emphasizing developmental stages.

Page 23: Stem Cells and Differentiation

• Discussion of stem cells and their role in forming specialized cells through differentiation.

Page 24: Gene Expression and Differentiation

• Examination of how genes dictate specialization of cells during development.

Page 25: Limb Regeneration Research

• Overview of regeneration in species such as axolotls and their potential implications for human medicine.

Page 26: Regeneration in Planarians

• Investigative study highlighting how planarians regenerate, focusing on stem cell usage and techniques.

Page 27: Chromosome Structure Check Understanding

• Assessment of knowledge regarding chromosome structure and behavior during mitosis.

Page 28: Mitosis Steps Illustration

• Inquiry into how mitosis outcomes can lead to genetically identical daughter cells without errors.

Page 29: Simple Explanation of Cells

• Summary of what comprises animal cells and their essential functions in basic terms.

Page 30: Structure of Animal Cells

• Further simplification of structures within animal cells and their functions.

Page 31: Regulating Cell Functions

• Examples of organelles in cells that regulate functions and maintain balance.

Page 32: Control Center and Genetic Material

• Exploration of cellular control areas, including DNA storage and replication.

Page 33: Apoptosis in Immune Response

• Illustrated role of apoptosis in regulating immune cells post-infection.

Page 34: Unit Practice Questions

• Review questions focusing on critical concepts from the unit to synthesize knowledge and prepare for assessments.

Page 35: Understanding Mitosis and Genetics

• Additional exercises reinforcing understanding of mitosis, chromosomes, and implications for living organisms.

Page 36: Analyzing Cancer Cell Behavior

• Practical task evaluating the metrics around cancer cells in contrast to healthy cells.

Mitosis is a vital process of cell division that ensures equal distribution of replicated genetic material to daughter cells. Mitosis consists of four main phases:

1. Prophase:

   • Chromatid condenses into visible chromosomes.

   • The nuclear envelope begins to break down.

   • The mitotic spindle forms from microtubules, and spindle fibers attach to the kinetochores on the chromosomes.

2. Metaphase:

   • Chromosomes align at the cell's equatorial plane, also known as the metaphase plate.

   • This alignment ensures that each daughter cell will receive one copy of each chromosome during the next phase.

   • The mitotic spindle is fully formed, and all chromosomes are attached to spindle fibers.

3. Anaphase:

   • Sister chromatids are pulled apart and move toward opposite poles of the cell.

   • The spindle fibers shorten, separating the chromatids, and ensuring that each pole has an identical set of chromosomes.

   • This phase is characterized by the segregation of the genetic material.

4. Telophase:

   • Chromatids reach the poles and begin to decondense back into chromatin.

   • The nuclear envelope starts to reform around each set of chromosomes.

   • Mitosis concludes with cytokinesis, the final step, where the cytoplasm divides, resulting in two distinct daughter cells, each with an identical set of chromosomes.