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Organelles
are specialized structures within the cell that have characteristic shapes; they preform specific functions in cellular growth, maintenance, and reproduction.
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cytoskeleton
is a network of protein filaments that extends throughout the cytosol
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Cytoskeleton: Microfilaments
these are the thinnest elements of the cytoskeleton. they are composed of the protein actin and are most prevalent at the edge of the cell
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Cytoskeleton: Microvilli
cell extensions: nonmotile, microscopic fingerlike projections of the plasma membrane
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Cytoskeleton: intermediate filaments
- these filaments are thicker than microfilaments but thinner than microtubules.
- -several different proteins can compose intermediate filaments which are exceptionally strong.
- they are found in parts of the cell subject to stress, help stabelize the position of organelles, and help attach cells to one another.
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Plasma membrane
Fluid mosaic lipid bilayer(phospholipids, cholestrol, and glycolipids) studded with proteins ; surrounds cytoplasm
Function- protects cellular contents; makes contact with other cells; contains channels, transporters, receptors, enzymes, cell identity markers and linker proteins; mediates the enrty and exit of substances
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Cytoplasm
cellular contents between the plasma membrane and the nucleus-cytosol and organelles
Function: site of all intracellular activities except those occuring in the nucleaus
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Cytosol
composed of water, solutes, suspended particles, lipid droplets, and glycogen granuals
Functions: medium in which many of the cell's metabolic reactions occur
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Cytoskeleton: Microtubules
larges and longest of the cytoskeleton components
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Centrosome
a pair of centrioles plus pericentriolar material
Function: the pericentriolar material contain tubulins which are used for growth of the mitotic spindle and microtubule formation
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Cilia and Flagella
motile cell surface projections that contain 20 microtubules and a basal body
Funtion: Cilia moves fluids over a cell's surface; flagella move an entire cell
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Ribosome
composed of two subunits containing ribosomal RNA and proteins; may be free in cytosol or attached to rough ER
Functions: Protein synthesis
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ER(Endoplasmic rericulum)
membranous network of flattened sacs or tubules. rough ER is covered by Ribosomes and is attached to the nucleus; smooth ER lacks ribosomes
Function: Rough ER synthesis glycoproteins and phospholipids the are transferred to cellular organelles, inserted into the plasma membrane, or secrected during exocytosis. Smooth ER synthesiszes fatty acids and steroides; inactivates or detoxifies drugs; removes the phosphate group from glucose 6 phosphate ; and stores and releases calcium ions in muscle cells.
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Golgi complex
consists of 20-30 flattened membranous sacs called cisternea; structurally and functionally divided into entry (cis) face, medial cisternea, and exit (trans) face.
Function: Entry face accepts proteins from rough ER; medial cisternae form glycoproteins, glycolipids, and lipoproteins; exut face modifies the molecules further then sorts and packages them for transport to their destinations
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lysosome
vesicles formed from the Golgi complex; contains digestive enzymes.
Function: fuses with and digests contents of endosomes, pinocytic vesicles, and phagosomes and transports final products of digestion into cytosol; digests worn-out organelles (autophagy), entire cells (autolysis) and extracellular materials.
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Peroxisome
Vesicles containing oxidases(oxidation enzymes) and catalase (decomposes hydrogen peroxide)
Function: oxidizes amino acids and fatty acids; detoxifies harmful substances, such as alcohol; produces hydrogen peroxide
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Proteasome
tiny barrel-shaped sturcture that contains proteases
Function: degrades unneeded, damaged, or faulty proteins by cutting them into small peptides
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Mitochondrion
consists of an outer and inner mitochondriral membrane, cristea and matrix
function: Site of aerobic cellular repiration reactions that produce most of a cell's ATP
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Nucleaus
consists of a nuclear envelope with pores, nucleoli, and chromosomes, which exist as a tangle mass of chromatin in interphase cells
Function: nuclearer pores control the movement of substances between the nucleus and cytoplasm, nucleoli produce ribosomes and chromosomes consist of genes that control cellular structure and direct cellular functions
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nuclear envelope
a double membrane that sperates the nucleus from the cytoplasm
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nuclear pore
extend through the nulcear envelope; each nulcear pore consists of a large central opening and they control the movement of substances between the nucleus and cytoplasm through passive diffusion
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nucleoli
spherical bodies that function in creating ribosomes. Each nucleoli is simply a cluster of protein, DNA and RNA; it is not enclosed by a membrane.
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genes
- hereditary untis found in the nucleus which control cellular structure and direct cellular activity
- -Genes are arranged along chromosomes
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Chromatin
the complex of RNA DNA and proteins is called chromatin
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