Chapter 7 Inside the Cell How do the parts inside the cell function individually Note size comparison Why are organelles compartmentalized The compartmentalization of eukaryotic cells offers two primary advantages 1 Separation of incompatible chemical reactions 2 Increasing the efficiency of chemical reactions Lysosomes STRUCTURE Lysosomes are single membrane bound structures containing approximately 40 different digestive enzymes Lysosomes are found in animal cells FUNCTION Vacuoles STRUCTURE Vacuoles are single membrane bound structures Can contain digestive enzymes and serve as recycling centers Majority are large storage containers Very large compared to lysosomes up to 80 of the cell volume FUNCTION Vacuoles act as storage depot Digestion and waste processing Mitochondria STRUCTURE Mitochondria have two membranes the inner one is folded into a series of sac like cristae The solution inside the cristae is called the mitochondrial matrix Mitochondria have their own DNA and manufacture their own ribosomes FUNCTION Chloroplasts STRUCTURE Most plant and algal cells have chloroplasts that like mitochondria have a double membrane and contain their own DNA Chloroplasts contain membrane bound flattened vesicles called thylakoids which are stacked into piles called grana Outside the thylakoids is the solution called the stroma FUNCTION http en wikipedia org wiki File FluorescentCells jpg Cytoskeleton The cytoskeleton composed of protein fibers gives the cell shape and structural stability and aids in In essence the cytoskeleton organizes all of the organelles and other cellular structures into a cohesive whole http www yellowtang org images three protein fi be c la 784 jpg The Dynamic Cytoskeleton The cytoskeleton is a complex network of fibers that helps maintain cell shape by providing structural support The cytoskeleton is dynamic it changes to alter the cell s shape to transport materials in the cell or to move the cell itself There are three types of cytoskeletal elements http www yellowtang org images three protein fi be c la 784 jpg Actin filaments can also be involved in movement by interacting with the motor protein myosin Actin myosin interactions can cause cell movements such as Microtubules Structure Composed of tubulin Bind to each other to form a dimer Compounds formed by joining to monomers Form a large hallow tube Each end of a microtubule has Microtubules grow and shrink in length as tubulin dimers Function To provide stability and are involved in movement Microtubules provide stability and are involved in movement they may also provide a structural framework for organelles Microtubules can act as railroad tracks transport vesicles move through the cell along these microtubule tracks in an energy dependent process Microtubules require ATP and kinesin for vesicle transport to occur Kinesin is a motor protein that converts chemical energy in ATP into mechanical work
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