1. Endomembrane System & Energy Production The endomembrane system is an internal membrane system within the cell that carries out a variety of functions such as: – synthesis of proteins and their transport – metabolism and movement of lipids – the detoxification of poisons. The membranes of the system are either directly in contact with each other or can communicate through the formation of vesicles (enclosed sacs made of membrane material). There are 5 major compartments: – endoplasmic reticulum (smooth&rough), – golgi apparatus, – Lysosomes – vacuoles.

2. Endoplasmic Reticulum(ER) largest of the endomembrane systems (over 1/2of the total) contains a network of tubes called cisternae (contains the inner lumen) connected to the nuclear envelope separating the cytosol from the inner lumen (much like our digestive system) self proliferating making its components from precursors (pieces of phospholipids) found in the cytosol 2 distinct compartments smooth & rough

3. Smooth ER Cisternae are rich in enzymes that carry out specialized tasks – Functions Synthesis of lipids – oils, phospholipids, & steroids – cells that produce and secrete these will be "rich" in smooth ER Metabolism of carbohydrates Detoxification of drugs and poisons – primary area is in the liver – detoxification occurs through adding hydroxyl functional groups (increases water solubility) – increased used (drugs & alcohol) causes proliferation of smooth ER in the liver which increases tolerance through faster clearance Storage of calcium ions – stored in muscle for use in contraction

4. Rough ER growing chain of polypeptides is threaded into the cisternae lumen from the ribosome – makes secretory proteins called glycoproteins (proteins with a carbohydrate covalently bonded) – makes membrane proteins that are anchored by hydrophobic attraction – once completed the proteins are transported through vesicles to their destination

5. The Golgi Apparatus (shipping & receiving) Consists of flattened sacs of cisternae – 2 distinct sides - CIS (receiving)&TRANS (shipping) – each side has different polarity and thickness – CIS face is close to the ER to receive incoming vesicles – packaged vesicles leave from the trans face Site of ER product modification (may modify the glycoprotein to make it better suited for its final destination) Produces its own polysaccharides to be fused with plasma membranes – molecular identification tags (phosphate groups or external molecules) aid in delivery to the correct location

6. Lysosomes A sac of hydrolytic enzymes – made in the rough ER & modified in the golgi – Acidic in nature – Special inner membrane with a 3D conformation that resists auto digestion – Can carry out intracellular digestion via phagocytosis (enfolding of membrane around an object) of membrane bound food vacuoles Digestion products (simple sugars, amino acids, & other monomers) pass back to the cytosol via exocytosis

7. Vacuoles Food storage structures in plants, protist, and fungal cells. Contain hydrolytic enzymes much like lysosomes Can be specialized in different animals to perform specific functions – Contractile vacuole protists use this structure to maintain salinity by adding and removing water – Central vacuole found in mature plants enclosed in a specialized membrane called a tonoplast enclosed material is called sap not cytosol can be used to store molecules, ions, waste, pigments, or anything needed for growth plays a major growth role

8. Mitochondria transform energy from their environment to be used by the host organism. They produce their own energy, are mobile, and divide (bud) to create new structures. – found in all Eukaryotes – site of cellular respiration – produces ATP through redox reactions in the mitochondrial membranes – the # of mitochondria present is based on the cell's (organism's) need for energy – has a smooth outer membrane and a folded inner membrane called cristae – contains its own DNA & ribosomes in the mitochrondrial matrix (an enclosed area in the inner membrane)

9. Chloroplasts transform energy from their environment to be used by the host organism – specialized member of the plastid family (chromoplasts & amyloplasts) – contain the green pigment chlorophyll – function in the photosynthetic production of sugar – consists of many flattened sacks called thalokoids (stacks are called granum) – fluid outside is called the stroma (contains the DNA & ribosomes)

10. Peroxisomes Structures is much like lysosomes. – Produce peroxide (H2O2) for the breakdown of fatty acids by oxidation for use in the mitochondria. – Also found in the liver as sites of detoxification. – Glycoxysomes are specialized structures in plant seeds that convert fatty acids to sugar used as a source of energy Cannot self replicate - product of lipids from the ER, proteins from the cytosol, & lipids made in the peroxisomes – they may split (bud) once the necessary parts are assembled and the size is sufficient