• Pokes out of almost every cell in the body
• Stiff, tiny, 1/1000 size of cell
• Req'd for wound healing + cell growth
• Involved in sonic hedgehog + wnt signaling systems
• Determines orientation of cell division, normal placement of some organs, and L/R asymmetry
• 9+2 microtubule ciliary axoneme in humans 

Primary Fxns of plasma membranes

• site of receptors, enzymes, transport proteins
• Communication with neighboring cells
• Respond to extracellular regulators
• Docking site for signaling molecules on cytosolic side
• 1st line defense against pathogens 

• Protein complex which allows transport of water soluble molecules across nuclear envelope
• Transport mRNA to cytosol ribosomes 
• # of pores changes depending upon stage of cell cycle
• More pores means cell is "busy" synthesizing and exporting mRNA

• Intermediate filament network of the nucleus which provides support for envelope and pore complexes
•  Also assists in DNA rep and cell division

• Has no membrane
• rRNA is transcribed 
• large and small ribosomes assembled
• telomerase RNA and protein components are assembled

• Reverse transcriptase which carries own RNA molecule as template to add repeat sequences to telomeres of chromosomes in order to prevent DNA loss arising from replication

• contains genome
• allow 2-way traffic of proteins + nucleic acids
• transcription of genes
• site of receptors + enzymes 

• makes a small subset of proteins from its DNA but most mito. proteins are imported from cytosol
• cell's "powerhouse"
• site of rate limiting steps in steroidogenesis (cholesterol transport)
• Plays central role in apoptosis 

• Intracellular digestion of macromolecules
• impermeable membrane bound compartment that houses degradative enzymes
• endosomes/ phagosomes deliver ingested microorganisms and other materials to lysosomes
• Deficiencies in lysosomal enzymes may cause disease
• pH ~4.5 

• all enriched with cholesterol, sphingolipids, and receptors
• nexus for signal transduction
• ion channels, transcytosis
• caveolae - invaginations of membrane 

• oxidative rxns
• destroys highly reactive H2O2
• Proteins synthesized in cytosol + imported 

• imports all secretory proteins and those destined for some organelles
• post-translational modification of proteins (ie: N-linked and O-linked glycosylation) 
• O-linked also occurs in golgi apparatus

• Makes steroid hormones and lipids
• Store and release calcium
• Detoxify drugs
• forms outer bilayer of nuclear envelope

• Process proteins made in RER
• Glycosylate proteins and lipids
• Direct mature proteins to final destination
• Vessicles come from ER and fuse with golgi (irreversibly from cis to trans face)
• golgi enzymes in each layer modify sugar side chains of secretory and memb. proteins and processed proteins segregate into vessicles destined for lysosomes or plasma membrane
• located in middle of cell near nucleus and centrosome

• centrosome: primary microtubule-organizing center (MTOC) and acts as spindle pole during mitosis - contains a pair of centrioles
• Centriole: short cylindrical array of microtubules  

component (subunit)

• microfilaments (actin)
• intermediate filaments (nuclear lamins)
• microtubules (α and β tubulin)

• proteins made on cytosolic ribosomes have targeting seq. for peroxisomes, mitochondria, and nucleus
• prots. synth on RER go to lysosomes and plasma membranes. all secretory prots go thru RER (secretory pathway). many membrane prots made on RER

• from deficient or defective hydrolases or absence of crucial activators
• most common in ashkenazi jews 

• polycystic kidney disease
• CNS defects
• basal cell carcinoma
• vision loss 

• areas of PM coated with clatharin
• fxn in receptor mediated endocytosis 

• sub-nuclear structures associated with transcriptional regulation, apoptosis, and genome stability 

• biogenesis, maturation, and recycling of snRNPs
•  histone mRNA processing
• assembles RNA which telomerase uses to add nucleotides to telomeres

• areas of the nucleus enriched with proteins req'd for splicing and processing of pre-mRNA  

• Foci of proteins involved in mRNA degredation

• aggrigations in the cytosol composed to proteins and mRNA that appear when the cell is under stress
• protect mRNA from harmful conditions