are specialized structures within the cell that have characteristic shapes; they preform specific functions in cellular growth, maintenance, and reproduction.
is a network of protein filaments that extends throughout the cytosol
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
cell extensions: nonmotile, microscopic fingerlike projections of the plasma membrane
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.
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
cellular contents between the plasma membrane and the nucleus-cytosol and organelles
Function: site of all intracellular activities except those occuring in the nucleaus
composed of water, solutes, suspended particles, lipid droplets, and glycogen granuals
Functions: medium in which many of the cell's metabolic reactions occur
larges and longest of the cytoskeleton components
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
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
composed of two subunits containing ribosomal RNA and proteins; may be free in cytosol or attached to rough ER
Functions: Protein synthesis
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.
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
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.
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
tiny barrel-shaped sturcture that contains proteases
Function: degrades unneeded, damaged, or faulty proteins by cutting them into small peptides
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
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
a double membrane that sperates the nucleus from the cytoplasm
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
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.
- hereditary untis found in the nucleus which control cellular structure and direct cellular activity
- -Genes are arranged along chromosomes
the complex of RNA DNA and proteins is called chromatin