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# Biologie Checkliste ## 1) Feinbau der Zelle Animal cells and plant cells belong to eukaryotes. They have a nucleus and many organelles (e.g., mitochondria, chloroplasts, endoplasmic reticulum). In contrast, bacterial cells are prokaryotes, which do not have a nucleus. **Differences between euka...

# Biologie Checkliste ## 1) Feinbau der Zelle Animal cells and plant cells belong to eukaryotes. They have a nucleus and many organelles (e.g., mitochondria, chloroplasts, endoplasmic reticulum). In contrast, bacterial cells are prokaryotes, which do not have a nucleus. **Differences between eukaryotes and prokaryotes:** * **Eukaryotes:** Nucleus, membrane-bound organelles, complex structure. * **Prokaryotes:** No nucleus, DNA free in the cytoplasm, simple structure. ## 2) Basic concept Compartmentalization Compartmentalization refers to the division of the cell into different reaction chambers (compartments) that are surrounded by biomembranes. This separation allows different chemical reactions to occur simultaneously and independently. Examples are cell organelles like the nucleus, endoplasmic reticulum (ER), and the Golgi apparatus. ## 3) Endosymbiont Theory The endosymbiont theory explains the origin of eukaryotes from prokaryotes. It is assumed that primitive eukaryotic cells arose from the uptake (endocytosis) of free-living bacteria. These bacteria were not digested but lived in symbiosis with the host cell. **Hints on the theory:** * Mitochondria and chloroplasts have their own DNA and ribosomes. * They reproduce by division, similar to bacteria. * The double membrane structure indicates a previous endocytosis.