Prokaryotic Organisms and Cell Division

Prokaryotic Organisms

• Definition: Single-celled microorganisms lacking a true nucleus and membrane-bound organelles
• Characteristics:
  • Small size (0.5-5.0 μm)
  • Simple cell structure
  • Rapid growth and reproduction
  • Can thrive in various environments
• Examples: Bacteria (e.g., E. coli, Staphylococcus aureus), Archaea (e.g., methanogens, thermophiles)

Cell Division

• Definition: Process by which a cell divides into two daughter cells
• Types:
  • Binary fission: Prokaryotic cells divide by simply splitting into two identical cells
  • Mitosis: Eukaryotic cells divide into two daughter cells with identical genetic material
  • Meiosis: Specialized cell division in eukaryotes that produces gametes (sperm or egg cells)
• Stages of cell division:
  • Interphase: Cell growth and preparation for division
  • Prophase: Chromatin condenses into visible chromosomes
  • Metaphase: Chromosomes align at the cell center
  • Anaphase: Sister chromatids separate
  • Telophase: Nuclear envelope reforms
  • Cytokinesis: Cytoplasm divides

Cellular Energy Production

• Definition: Process by which cells generate energy from nutrients
• Types:
  • Cellular respiration: Process by which cells generate energy from glucose (and other organic molecules)
  • Fermentation: Anaerobic process that generates energy from glucose (e.g., yeast fermentation)
• ATP (Adenosine Triphosphate): Energy currency of cells, generated through cellular respiration and fermentation

Eukaryotic Microorganisms

• Definition: Microorganisms with a true nucleus and membrane-bound organelles
• Characteristics:
  • Larger size (5-100 μm) compared to prokaryotes
  • Complex cell structure with organelles
  • Slower growth and reproduction compared to prokaryotes
• Examples: Protists (e.g., protozoa, algae), fungi (e.g., yeast, mushrooms), plants, animals

Photosynthetic Processes

• Definition: Process by which cells convert light energy into chemical energy
• Types:
  • Oxygenic photosynthesis: Generates oxygen as a byproduct (e.g., plants, algae, cyanobacteria)
  • Anoxygenic photosynthesis: Does not generate oxygen as a byproduct (e.g., purple sulfur bacteria)
• Light-dependent reactions: Light energy is absorbed and converted into ATP and NADPH
• Light-independent reactions (Calvin cycle): ATP and NADPH are used to convert CO2 into glucose

Cellular Respiration

• Definition: Process by which cells generate energy from glucose (and other organic molecules)
• Stages:
  • Glycolysis: Glucose is broken down into pyruvate, generating ATP and NADH
  • Citric acid cycle (Krebs cycle): Pyruvate is converted into ATP, NADH, and FADH2
  • Electron transport chain: ATP is generated through the transfer of electrons from NADH and FADH2
  • Oxidative phosphorylation: ATP is generated through the transfer of electrons from NADH and FADH2

Prokaryotic Organisms

• Single-celled microorganisms lacking a true nucleus and membrane-bound organelles
• Characterized by small size (0.5-5.0 μm), simple cell structure, rapid growth, and reproduction
• Can thrive in various environments
• Examples include bacteria like E. coli and Staphylococcus aureus, and archaea like methanogens and thermophiles

Cell Division

• Process by which a cell divides into two daughter cells
• Types of cell division include binary fission, mitosis, and meiosis
• Binary fission involves prokaryotic cells dividing into two identical cells
• Mitosis results in two daughter cells with identical genetic material in eukaryotes
• Meiosis produces gametes (sperm or egg cells) in eukaryotes

Stages of Cell Division

• Interphase: Cell growth and preparation for division
• Prophase: Chromatin condenses into visible chromosomes
• Metaphase: Chromosomes align at the cell center
• Anaphase: Sister chromatids separate
• Telophase: Nuclear envelope reforms
• Cytokinesis: Cytoplasm divides

Cellular Energy Production

• Process by which cells generate energy from nutrients
• Types of energy production include cellular respiration and fermentation
• Cellular respiration generates energy from glucose (and other organic molecules)
• Fermentation generates energy from glucose in anaerobic conditions
• ATP (Adenosine Triphosphate) is the energy currency of cells, generated through cellular respiration and fermentation

Eukaryotic Microorganisms

• Microorganisms with a true nucleus and membrane-bound organelles
• Characterized by larger size (5-100 μm) compared to prokaryotes
• Complex cell structure with organelles
• Slower growth and reproduction compared to prokaryotes
• Examples include protists, fungi, plants, and animals

Photosynthetic Processes

• Process by which cells convert light energy into chemical energy
• Types of photosynthesis include oxygenic and anoxygenic photosynthesis
• Oxygenic photosynthesis generates oxygen as a byproduct
• Anoxygenic photosynthesis does not generate oxygen as a byproduct
• Light-dependent reactions absorb light energy and convert it into ATP and NADPH
• Light-independent reactions (Calvin cycle) convert CO2 into glucose using ATP and NADPH

Cellular Respiration

• Process by which cells generate energy from glucose (and other organic molecules)
• Stages of cellular respiration include glycolysis, citric acid cycle, electron transport chain, and oxidative phosphorylation
• Glycolysis breaks down glucose into pyruvate, generating ATP and NADH
• Citric acid cycle (Krebs cycle) converts pyruvate into ATP, NADH, and FADH2
• Electron transport chain generates ATP through the transfer of electrons from NADH and FADH2
• Oxidative phosphorylation generates ATP through the transfer of electrons from NADH and FADH2