While focus is on prokaryotic cells and viruses, eukaryotic pathogens like malaria, Entamoeba histolytica, Giardia, fungi, and parasitic worms also cause diseases in humans.
It's crucial to understand eukaryotic cell structure to study these pathogens effectively.
Differences Between Prokaryotes and Eukaryotes
Eukaryotes:
More complex and larger.
Have organelles, which are membrane-bound substructures.
Have undulating flagella, simpler than prokaryotic rotating flagella.
Simple cell walls (e.g., plant cells with cellulose).
Functions within organelles rather than in the cytoplasm or plasma membrane.
Key Structures of Eukaryotic Cells
Nucleus
Characteristics:
Contains nuclear membrane, chromatin (DNA), and nucleolus.
Pores in the membrane allow exchange (e.g., nucleotides in, mRNA out).
Entry point for some viruses.
Function: Acts as the "data center" of the cell.
Endoplasmic Reticulum (ER)
Construction Crew:
Rough ER: Ribosomes embedded, make secretory and membrane proteins.
Smooth ER: Synthesizes lipids for cell membranes.
Mitochondria
Powerhouse: Produces ATP, the cell's energy source.
Golgi Apparatus
Pack and Ship:
Modifies proteins from the Rough ER.
Packages and transports them (e.g., to the cell membrane).
Cytoskeleton
Structural Support:
Composed of protein microtubules.
Provides shape, helps in mitosis, and facilitates intracellular transport.
Features Specific to Plant Cells
Chloroplasts
Site of photosynthesis, turning sunlight into sugar.
Considered a "power plant" as well.
Other Structures
Plant cells have mitochondria and other organelles similar to animal cells.
Ribosomes can either be on the Rough ER or free in the cytoplasm.
Conclusion
Highlighted structures and functions are crucial for understanding eukaryotic cells in the context of pathogens and diseases.
Essential knowledge for exams and further study.
Next Topic
Origins of organelles and eukaryotes will be discussed in the following lecture snippet.