Chapter_10_Cell_Cycle_and_Mitosis_111

Cell Cycle and Cell Division Overview

Chapter 10

Page 1: Introduction

• Introduces the concept of cell cycle and cell division.

Page 2: Critical Thinking

• Understanding images related to cell division is encouraged.

Page 3: Introduction to Cell Division

Part 1

• Overview of cell division processes.

Page 4: Learning Objectives

• Understand why cells divide: \

  • The necessity of cell division in living organisms.

• Compare cell division purposes: \

  • Differences in prokaryotic and eukaryotic cells.

Page 5: Understanding Why Cells Divide

Use by Organisms

• Single-celled organisms:

  1. Reproduction (e.g., amoeba divides to form new organisms).

• Multicellular organisms:

  1. Growth and development (e.g., sand dollar embryo).

  2. Tissue renewal (e.g., new blood cells from dividing bone marrow).

  3. Repair (not explicitly mentioned but also inferred).

  4. Replacement of dead cells.

Page 6: Cell Division Overview

Key Points

• During cell division, cells:

  1. Duplicate their DNA.

  2. Divide into two daughter cells.

• Importance: Ensures genetic fidelity except in meiosis.

Page 7: Prokaryotic Cell Cycle & Division

Part 2

• Introduces prokaryotic cell cycle dynamics.

Page 8: Learning Objectives

• Describe prokaryotic cell cycle: \

• Explain triggers for cell division: \

• Summarize binary fission process.

Page 9: Key Terms

• Binary fission: the process of asexual reproduction in prokaryotes.

Page 10: Prokaryotic Cell Cycle

Phases Overview

• Three phases:

  1. Growth phase

  • Cell mass increases.

  2. Chromosomal replication phase.

  3. Separation phase

  • DNA and physical division of the bacterial cell.

Page 11: Prokaryotic Reproduction

• Prokaryotic cells reproduce asexually via binary fission.

• Results in two genetically identical daughter cells.

• No genetic variation occurs.

Page 12: Generation Time

Factors Influencing Length

• Varies by organism from < 1/2 hr to several days.

• Influenced by:

  1. Environmental conditions

  2. Cellular mass (size).

• Surface area must support the cell's volume.

Page 13: Eukaryotic Cell Cycle

Part 3

• Prepares to explore eukaryotic cell division processes.

Page 14: Learning Objectives

• Three stages of interphase: \

• Cytokinesis process explanation: \

• Define G0 phase and its significance.

• Identify cell cycle checkpoints.

Page 15: Key Terms

• Interphase, Mitotic phase, Karyokinesis, Cytokinesis

• G1 phase, S phase, G2 phase, G0 phase, Quiescent, Senescent, Differentiated.

Page 16: Eukaryotic Cell Cycle Overview

• Two major phases:

  1. Interphase

  2. Mitotic phase

• Highly conserved across all eukaryotes.

Page 17: G0 Phase Overview

Descriptions of Various States

1. Quiescent:

   • Reversible, preparatory state before entering the cell cycle.

2. Senescent:

   • Non-replicating due to damage but performs normal functions.

3. Differentiated:

   • Terminally differentiated cells fulfilling main functions indefinitely.

Page 18: Interphase Components

• G1 Phase: Initial growth and cell function.

• S Phase: DNA replication.

• G2 Phase: Prepares for mitosis.

Note: Chromatin is not condensed during interphase.

Page 19: Mitotic Phase Overview

Key Processes

1. Karyokinesis (Mitosis):

   • Division of the nucleus into daughter nuclei.

   • Five stages: Prophase, Prometaphase, Metaphase, Anaphase, Telophase.

2. Cytokinesis:

   • Division of cytoplasm and organelles.

Page 20: Eukaryotic Cell Division

Mitotic Phase

• Deep dive into mitosis and cellular behavior.

Page 21: Learning Objectives

• Discuss stages of mitotic phase and chromosome behavior.

• Explain functions of key proteins.

Page 22: Key Terms in Mitosis

• Prophase, Prometaphase, Metaphase, Anaphase, Telophase, Cleavage, Spindle apparatus, Centrioles, Microtubules, Astral microtubules, Polar microtubules, Kinetochore.

Page 23: Stages of Mitosis

Detailed Staging

• Prophase: Chromosomes condense; mitotic spindle forms.

• Prometaphase: Nuclear envelope breaks down; kinetochores develop.

• Metaphase: Alignment along the metaphase plate.

• Anaphase: Sister chromatids are pulled apart.

• Telophase: Chromosomes reach poles, nuclear envelope re-forms.

• Cytokinesis: Cell splits into daughter cells.

Page 24: Eukaryotic Spindle Apparatus

• Centrosomes serve as microtubule organizing centers, critical during mitosis.

Page 25: Mitotic Spindle Structure

• Composed of polar, astral, and kinetochore microtubules originating from the centrosomes.

Page 26: Prophase in Detail

• Nuclear envelope breaks down; chromosomes condense with help from condensin proteins.

Page 27: Prometaphase Detailed Steps

1. Nuclear envelope disintegrates.

2. Kinetochores manifest at centromeres; spindle microtubules attach.

Page 28: Metaphase Outline

• Chromosomes align on the metaphase plate with sister chromatids attached by cohesion proteins.

Page 29: Anaphase Breakdown

1. Sister chromatids separate as cohesion proteins break down.

2. Separated chromatids pulled to opposite poles.

Page 30: Telophase Breakdown

1. Chromosomes de-condense; nuclear envelopes reform around each set.

2. Mitotic spindle disassembles.

Page 31: G2 of Interphase Overview

• Description of centrosomes, chromatin, and early mitotic spindle appearance.

Page 32: Key Elements of Mitosis

• Overview of components undergoing changes during mitosis.

Page 33: Cytokinesis Overview

Animal Cells

1. Cleavage furrow forms: Plasma membrane contracts, pinching the cell into two.

Plant Cells

1. Cell plate formation: Golgi vesicles create a dividing plate against the cell's center.

Page 34: Cell Cycle Control Overview

Part 5

• Emphasizes regulation during the cell cycle.

Page 35: Learning Objectives

• Identify cell cycle checkpoints and their significance.

• Understand cancer development mechanisms.

Page 36: Key Terms in Cell Cycle Control

• Cancer, Proto-oncogenes, Oncogenes, Tumor suppressor genes.

Page 37: Control Mechanisms in the Cell Cycle

• Checkpoints prevent progression until necessary conditions are met.

• Types of signals: external triggers and internal factors.

Page 38: Focus on Checkpoints

• G1 checkpoint: Assesses cell size, DNA integrity, nutrients, and growth signals.

• G2 checkpoint: Verifies DNA replication and damage repair.

• M checkpoint: Confirms chromosome alignment and attachment.

Page 39: Cancer and the Cell Cycle Overview

Cancer Development Process

1. Mutation in DNA leads to abnormal protein production.

2. Accumulating mutations result in uncontrolled cell growth.

3. Growth of mutated cells surpass normal cell growth.

Page 40: Proto-oncogenes

• Genes that regulate cell cycle positively; mutations can lead to cancer.

Page 41: Tumor Suppressor Genes

• Normal gene function prevents uncontrolled cell division; mutations inhibit this effect, leading to cancer.