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Chen_Queenie_Block4_MM2 (Prokaryotic Cells (Organelles (Capsule (jelly…

- - - - Bacterial chromosomes (DNA) bunched together
      - does not have membrane
    - - -Interior of cell
      - cytosol
        
        Aqueous component of cytoplasm
    - - locomotive attachment structures on surface of some prokaryotes
    - - selective barrier that allows enough oxygen, nutrients, and wastes to service cell
      - Bigger surface area to volume ratio = more material exchanges between cell and surroundings
        
        microvilli
        
        long, thin projections from cell surface;
        allows big increase in surface area but not volume
      - bilayer of phospholipids with proteins embedded or attached onto it and carbohydrate side chains on the outer surface
    - - made of ribosomal RNA (rRNA) & protein
      - Function
        
        synthesize proteins
    - - rigid structure outside of plasma membrane
      - Function
        
        provides receptor sites for antibiotics and viruses (bacteria)
        
        protects cell from environment (archaea)
      - subunits
        
        peptidoglycans (bacteria)
        
        proteins called S-Layers (archaea)
    - - jelly-like outermost coating
      - contains water to prevent desiccation
      - prevents cell from being engulfed by eukaryotes
      - enhances ability to cause diseases (bacteria)
    - - Locomotion organelles at end of some prokaryotes
      - made of membrane-enclosed microtubules in (9+2) arrangement
- - - - Organelles
        
        Organelles in Plants and Animals
        
        Nucleus
        
        Function
        
        encloses nucleus & separates its contents from the cytoplasm
        
        stores DNA in units (chromosomes)
        
        made of chromatin
        
        complex fibers made of proteins and DNA
        
        carry genetic information
        
        nucleolus (pl. nucleoli)
        
        densely stained granules and fibers adjoining parts of the chromatin within the nucleus
        
        Function
        
        synthesizes ribosomal RNA which combines with proteins into ribosomal subunits
        
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        Nuclear Envelope
        
        nuclear matrix
        
        fibers extending throughout nuclear interior
        
        double membrane
        
        have pores (100nm diameter)
        
        both continuous at pores
        
        membranes separated by space of 20-40nm
        
        both lipid bilayers with associated proteins
        
        lined by nuclear lamina
        
        netlike array of protein filaments
        
        Function
        
        maintains shape of cell
        
        supports nuclear envelope
        
        Ribosomes
        
        made of rRNA & protein
        
        Function
        
        protein synthesis
        
        has nucleoli
        
        free ribosomes
        
        suspended in cytosol
        
        Function
        
        makes proteins that function in the cytosol
        
        structurally identical; can alternate between the two
        
        bound ribosomes
        
        attached to outside of endoplasmic reticulum or nuclear envelope
        
        Function
        
        make proteins for insertion into membranes, for packaging within certain organelles, or for secretion
        
        Endomembrane System
        
        Endoplasmic Reticulum (ER)
        
        continuous with nuclear envelope
        
        consists of network of cisternae
        
        network of ER membranes that separates ER lumen (cisternal space) from cytosol
        
        Two regions
        
        Smooth ER
        
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        Rough ER
        
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        Golgi Appartatus
        
        Function
        
        modifies, stores, and then ships products of the ER to other places
        
        makes certain macromolecules, such as polysaccharides
        
        stacks of cisternae with membranes that protects inside from cytosol
        
        opposite sides of cisternae stacks
        
        cis face
        
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        trans face
        
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        Mitochondria (singular, mitochondrion)
        
        2 membranes of phospholipid bilayers with imbedded proteins
        
        inner membrane has cristae
        
        increases surface area without changing the volume drastically
        
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        2 internal compartments created by the inner membrane
        
        intermembrane space
        
        mitochondrial matrix
        
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        Function
        
        cellular respiration
        
        membrane proteins made by free ribosomes in cytosol
        
        has small amount of DNA
        
        can synthesize own proteins
        
        Peroxisomes
        
        Function
        
        breaks down fatty acids into smaller molecules that are sent to the mitochondria
        
        detoxify alcohol and poisons (peroxisome metabolism)
        
        produce hydrogen peroxide (H2O2)
        
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        glyoxysomes
        
        in fat-storing tissues of plant seeds
        
        Function
        
        converts fatty acids to sugar for energy and carbon usage (in plant seeds)
        
        has one membrane
        
        grows from proteins made in the cytosol, lipids made in ER, and their own lipids
        
        Cytoskeleton
        
        Microfilaments (Actin Filaments) (7nm)
        
        subunits: Actin
        
        Function
        
        resists stretching; compresses
        
        muscle contraction
        
        helps cell change shape
        
        cytoplasmic streaming
        
        cell motility through pseudopods
        
        cell division through cleavage
        
        motor protein: Myosin
        
        structure: 2 intertwined actin polymers
        
        direction: bidirectional polymerization in (+) and (-) directions
        
        Intermediate Filaments (10nm)
        
        subunits: Keratin & others
        
        structure: fibrous protein supercoiled into fibers
        
        Function
        
        resists stretching and compression
        
        forms nuclear lamina
        
        anchorage of nuclear envelope
        
        helps with cell-to-cell cohesion
        
        Microtubules (Tubulin Polymers) (25nm)
        
        structure: hollow cylinders formed by tubulin polymers
        
        grown from centrosomes & basal bodies (MTOC)
        
        1 more item...
        
        subunits: tubulin dimers
        
        alpha-tubulin
        
        beta-tubulin
        
        Function
        
        resists compression
        
        cell motility through cilia and flagella
        
        cell division through chromosome movement
        
        moves organelles
        
        motor proteins
        
        cytoplasmic dynein
        
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        kinesin
        
        2 more items...
        
        axonemal dynein
        
        2 more items...
        
        direction: unidirectional polymerization from (-) to (+)
        
        Chloroplasts
        
        type of plastid
        
        contains chlorophyll, enzymes, and other molecules that contribute to photosynthesis
        
        contains thylakoids
        
        stacked into granum
        
        contains stroma
        
        contains chloroplast DNA, ribosomes, and enzymes
        
        Function
        
        photosynthesis
        
        3 membranes
        
        outer membrane
        
        inner membrane
        
        transparent
        
        allows light to travel to thylakoid membrane
        
        thylakoid membrane
        
        Function
        
        captures light energy for photsynthesis
        
        surrounds thylakoids
        
        membrane proteins made from free ribosomes
        
        contains small amount of DNA
        
        can synthesize own proteins
        
        Cell Wall
        
        structure
        
        microfibrils made of cellulose are embedded in a matrix of other proteins and polysaccharides
        
        Function
        
        protects cell
        
        maintains cell shape
        
        prevents excessive intake of water in cell
        
        helps cell fight gravity
        
        Layers
        
        primary cell wall
        
        weak; for young plants
        
        middle lamella
        
        glues ajacent primary cell walls together with pectins
        
        secondary cell wall
        
        strong; provides support and protection
        
        often several layers
        
        Plasmodesmata
        
        channels between ajacent cell walls
        
        Function
        
        allows ajacent cell walls to exchange materials with each other
        
        Vacuoles
        
        central vacuole
        
        enclosed by a membrane (tonoplast)
        
        makes cell sap different from cytosol
        
        made from smaller vacuoles
        
        Function
        
        stores organic compounds, inorganic ions, and pigments
        
        disposal site for metabolic by-products
        
        stores poisons to protect cell
        
        contributes to cell growth
        
        carries out hydrolysis of macromolecules
        
        part of endomembrane system in plant cells
    - - Organelles
        
        Lysosomes
        
        part of endomembrane system in animal cells
        
        made of lysosomal membrane
        
        both made from rough ER and Golgi apparatus
        
        contain active hydrolytic enzymes
        
        Function
        
        digest food or damaged organelle
        
        Phagocytosis
        
        food vacuole fuses with lysosome and is digested into nutrients for cell
        
        Autophagy
        
        vesicle containing damaged organelle or cytosol fuses with lysosome and forms organic monomers that can be reused
        
        Extracellular Matrix (ECM)
        
        collagen + fibronectin + proteoglycan
        
        Function
        
        helps bind cells together
        
        regulates adhesion
        
        Intercellular Junctions
        
        desmosomes
        
        hold neighboring cells together into strong sheets; stronger than tight junctions
        
        gap junctions
        
        provide cytoplasmic channels between ajacent cells
        
        allows cells to communicate with one another and share materials
        
        tight junctions
        
        watertight seal between ajacent cells
        
        prevents liquid from going across layer of cells
        
        Centrioles
        
        a pair of centrioles make up a centrosome in animal cells
        
        made up of 9 microtubule triplets
        
        Function
        
        duplicate for cell division (mitosis)
        
        helps organize microtubule assembly
        
        Flagella
        
        in some animal cells
        
        locomotion organelles
        
        made of membrane-enclosed microtubules in (9+2) arrangement