Cell Division: Mitosis and Meiosis

Cell Division

• ** Mitosis **:
  • Process of cell division that results in two daughter cells with same number of chromosomes as parent cell
  • Consists of four stages: prophase, metaphase, anaphase, and telophase
  • Occurs in somatic cells (non-reproductive cells)
• ** Meiosis **:
  • Process of cell division that results in four daughter cells with half the number of chromosomes as parent cell
  • Consists of two successive cell divisions (meiosis I and meiosis II)
  • Occurs in reproductive cells (gametes)

Prokaryotic Organisms

• ** Characteristics **:
  • Lack true nucleus and membrane-bound organelles
  • Typically single-celled and small in size
  • Have a single circular chromosome
  • Examples: bacteria, archaea
• ** Cell Structure **:
  • Cell wall provides support and maintains cell shape
  • Cytoplasm contains ribosomes, genetic material, and various enzymes
  • No membrane-bound organelles

Eukaryotic Microorganisms

• ** Characteristics **:
  • Have a true nucleus and membrane-bound organelles
  • Typically single-celled, but can be multicellular
  • Examples: protists, fungi, algae
• ** Cell Structure **:
  • True nucleus contains genetic material
  • Membrane-bound organelles (e.g. mitochondria, chloroplasts) perform specific functions
  • Cytoskeleton provides support and shape

Cellular Energy Production

• ** Cellular Respiration **:
  • Process of generating energy (ATP) from glucose
  • Occurs in mitochondria
  • Involves three stages: glycolysis, citric acid cycle, oxidative phosphorylation
• ** Fermentation **:
  • Process of generating energy (ATP) from glucose in absence of oxygen
  • Occurs in cytoplasm
  • Results in lactic acid or ethanol and carbon dioxide as byproducts

Photosynthetic Processes

• ** Overall Equation **: 6 CO2 + 6 H2O + light energy → C6H12O6 (glucose) + 6 O2
• ** Light-Dependent Reactions **:
  • Occur in thylakoid membranes of chloroplasts
  • Light energy excites electrons, which generate ATP and NADPH
• ** Light-Independent Reactions (Calvin Cycle) **:
  • Occur in stroma of chloroplasts
  • ATP and NADPH from light-dependent reactions are used to fix CO2 into glucose

Cellular Respiration

• ** Aerobic Respiration **:
  • Process of generating energy (ATP) from glucose in presence of oxygen
  • Occurs in mitochondria
  • Involves three stages: glycolysis, citric acid cycle, oxidative phosphorylation
• ** Electron Transport Chain **:
  • Series of protein complexes that generate ATP during oxidative phosphorylation
  • Electrons from NADH and FADH2 are passed through the transport chain, generating a proton gradient
  • ATP synthase uses the proton gradient to produce ATP

Cell Division

• Mitosis:
  • Results in two daughter cells with same number of chromosomes as parent cell
  • Four stages: prophase, metaphase, anaphase, and telophase
  • Occurs in somatic cells (non-reproductive cells)
• Meiosis:
  • Results in four daughter cells with half the number of chromosomes as parent cell
  • Two successive cell divisions: meiosis I and meiosis II
  • Occurs in reproductive cells (gametes)

Prokaryotic Organisms

• Characteristics:
  • Lack true nucleus and membrane-bound organelles
  • Typically single-celled and small in size
  • Have a single circular chromosome
  • Examples: bacteria, archaea
• Cell Structure:
  • Cell wall provides support and maintains cell shape
  • Cytoplasm contains ribosomes, genetic material, and various enzymes
  • No membrane-bound organelles

Eukaryotic Microorganisms

• Characteristics:
  • Have a true nucleus and membrane-bound organelles
  • Typically single-celled, but can be multicellular
  • Examples: protists, fungi, algae
• Cell Structure:
  • True nucleus contains genetic material
  • Membrane-bound organelles (e.g.mitochondria, chloroplasts) perform specific functions
  • Cytoskeleton provides support and shape

Cellular Energy Production

• Cellular Respiration:
  • Generates energy (ATP) from glucose
  • Occurs in mitochondria
  • Involves three stages: glycolysis, citric acid cycle, oxidative phosphorylation
• Fermentation:
  • Generates energy (ATP) from glucose in absence of oxygen
  • Occurs in cytoplasm
  • Results in lactic acid or ethanol and carbon dioxide as byproducts

Photosynthetic Processes

• Overall Equation:
  • 6 CO2 + 6 H2O + light energy → C6H12O6 (glucose) + 6 O2
• Light-Dependent Reactions:
  • Occur in thylakoid membranes of chloroplasts
  • Light energy excites electrons, which generate ATP and NADPH
• Light-Independent Reactions (Calvin Cycle):
  • Occur in stroma of chloroplasts
  • ATP and NADPH from light-dependent reactions are used to fix CO2 into glucose

Cellular Respiration

• Aerobic Respiration:
  • Generates energy (ATP) from glucose in presence of oxygen
  • Occurs in mitochondria
  • Involves three stages: glycolysis, citric acid cycle, oxidative phosphorylation
• Electron Transport Chain:
  • Series of protein complexes that generate ATP during oxidative phosphorylation
  • Electrons from NADH and FADH2 are passed through the transport chain, generating a proton gradient
  • ATP synthase uses the proton gradient to produce ATP