Lecture 3: Cells in Their Environment
Course Information
- Course: 4BBY1030 Cell Biology & Neuroscience
- Instructors: Prof Clemens Kiecker and Dr Suba Poopalasundaram
- Dates: 3rd and 4th October 2024
- Institution: King's College London
Learning Outcomes
- Speculate on the origins of cellular life forms on Earth
- Explain cellular specialization in multicellularity
- Provide an overview of cellular and subcellular pathogens
Key Topics Covered
Chapter 1: The Origins of Cellular Life
Earth's Early Atmosphere
- Methane, carbon dioxide prevalent
- Lack of oxygen, high temperatures
- Energy from lightning and volcanic eruptions
- No UV protection due to the absence of ozone
- Conditions favorable for spontaneous reactions and formation of carbon compounds
Formation of the First Cell
- Ideal conditions: high temperature and pressure
- Catalysts like metals
- Self-assembly of polymers
- RNA as self-replicating molecules
- Compartmentalization through membrane formation by phospholipids
RNA as the First Genetic Material
- Stores genetic information, self-replication ability
- Acts as an enzyme
- Prone to mutations
Evolution of LUCA (Last Universal Common Ancestor)
- Involvement of molecules like HCHO, HCN, glyceraldehyde
- Catalysts and conditions in hydrothermal vents
- Development of RNA world, transition to DNA for stability
- Formation of lipid bilayers
Bacteria and Archaea
- Single cellular compartment, no organelles
- Specializations: flagella, extremophiles
- Rapid reproduction
- Human microbiome: 40,000 species, 30-50 trillion bacterial cells
Endosymbiotic Theory
- Symbiosis between anaerobic eukaryotes and aerobic bacteria
- Development of mitochondria and chlorophyll-based photosynthesis
Chapter 2: Multicellularity
Cellular Specialization
- Different cell types: heart, blood, kidney, neurons, bone, gut epithelial cells
Reproduction: Ex Ovo Omnia
- Asexual reproduction in hydra and yeast
- Sexual reproduction vs. parthenogenesis
- Embryogenesis and its needs for cell division and differentiation
Origins of Multicellularity
- Volvox as an example of colonial algae
- Differentiation into somatic and germ cells
Social Behavior in Cells
- Dictyostelium discoideum (slime mold) displaying multicellular traits
Chapter 3: Pathogens
Overview of Pathogens
- Includes bacteria, viruses, fungi, and protozoans
Bacterial Pathogens
- Significant historical discoveries: Koch and cholera, Ehrlich's Salvarsan, Fleming's penicillin
- MRSA and cyanobacteria as toxin producers
Viruses
- Structure: virion with DNA/RNA and protein coat
- Examples: Retroviruses, herpes, ancient Pithovirus
Other Pathogens
- Fungi: Candida, Cryptococcus, coccidioidomycosis
- Protozoans: malaria, toxoplasmosis, giardiasis, cryptosporidiosis
Recommended Reading
- "Cell Biology" by Pollard, Earnshaw, Lippincott-Schwartz, Johnson - 3rd edition
- Note: Use this reading to supplement learning, not required to read cover-to-cover.
Contact Information
Note: Kings College London reserves all rights to lecture materials.