60 lines
4.8 KiB
Markdown
60 lines
4.8 KiB
Markdown
[[Cell Structure and Function]]
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Cell compartmentalization is how eukaryotic cells use membranes to separate specific metabolic processes and enzymatic reactions.
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# Summary
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* Internal membranes help cells separate competing interactions and increase surface area where reactions occur
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* Each organelle maintains its own conditions
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* Folded membrane like mitochondrial cristae and chloroplast thylakoids pack more reaction surface into a small space
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* Prokaryotes lack membrane bound organelles, so translation and transcription can occur in the same space
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# Eukaryotic Organization: Separate Compartments for Separate Jobs
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Eukaryotic cells have membranes, prokaryotic cells don't. Eukaryotic cells have organelles which are compartmentalized because they're surrounded by a membrane.
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# Nucleus
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* Houses DNA and cell control
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* Surrounded by a double membrane with nuclear pores for transport
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* Creates a protected environment for DNA storage and RNA production
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* Separates transcription (making DNA from RNA) from translation (making proteins from RNA)
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# Endoplasmic Reticulum
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* Rough ER creates specialized area for protein folding and quality control. Connects directly to nuclear membrane for efficient RNA transport.
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* Smooth ER no ribosomes, specializes in lipid production and detoxification. Separate environment for lipid synthesis enzymes, stores calcium ions in a controlled safe space.
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# Golgi Apparatus
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* Receives proteins from ER and modifies them
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* Sorts and packages proteins into vesicles for delivery
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* Works a sequential processing line with enzymes in different cisternae
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* Different cisternae have different conditions for different processing steps
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# Lysosomes
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* Contains hydrolytic enzymes that work best in acidic environments
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* Breaks down cellular waste, old organelles, and foreign material
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* Keeps destructive enzymes safely contained
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# Mitochondria
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* Generates ATP from aerobic respiration
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* Double membrane, outer is smooth and protective, inner is folded into a cristae to increase SA
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* Contains own DNA and ribosomes (evidence they evolved from once free living prokaryotes)
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# Peroxisomes
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* Breaks down fatty acids and toxic molecules
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* Enzymes that produce and break down hydrogen peroxide
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* Safe contained place for these dangerous reactions
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# Vacuoles
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* Stores nutrients waste products and water
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* Helps maintain turgor pressure in plant cells
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* Isolated environment for materials that might hamper other processes
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# Why Compartmentalization Improves Efficiency
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* Creates specialized environments (e.g. enzymes like acidic environments, others don't)
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* Increases surface area for reactions
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* Separates competing reactions, some processes would interfere with others
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* Allows proteins to go where they're needed as the membranes hold proteins
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* Prokaryotic cells can do translation and transcription in the same region because they lack compartmentalization, limiting how complex they can become.
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| Term | Definition |
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| ------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------- |
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| compartmentalization | The division of the eukaryotic cell into distinct membrane-bound regions that separate different metabolic processes and enzymatic reactions. |
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| enzymatic reaction | Chemical reactions catalyzed by enzymes that occur within specific cellular compartments to facilitate metabolic processes. |
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| eukaryotic cell | Cells that contain a membrane-bound nucleus and internal membrane-bound organelles, found in animals, plants, fungi, and protists. |
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| internal membrane | Membranes within eukaryotic cells that divide the cell into compartments with specialized functions. |
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| intracellular metabolic process | Chemical reactions and pathways that occur within the cell to build up or break down molecules for energy and biosynthesis. |
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| membrane-bound organelle | Specialized structures within eukaryotic cells enclosed by a membrane that perform specific cellular functions. |
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| membrane-bound structure | Organelles and compartments in eukaryotic cells that are enclosed by a lipid bilayer membrane, separating their contents from the cytoplasm. |
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| organelle | Membrane-bound or non-membrane-bound structures within eukaryotic cells that perform specific cellular functions. |
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| surface area | The total area of a membrane available for chemical reactions and cellular processes to occur. | |