Functions of the Nucleus 1. Role in cell division. 2. Influences cytoplasmic events. 3. Contains codes for protein synthesis.
Nuclear Membrane 1. double bilayer outer + inner membranes = nuclear envelope
2. nuclear pore complexes a. nuclear pores b. exhibit selective permeability c. RNA needs to exit the nucleus d. proteins enter nucleus to regulate the DNA
Nucleolus ribosomes are built here ribosome subunits exit nucleus through nuclear pores
Ribosomes substructures that are the “protein factories” of the cell A. Can be free or attached B. Not membrane-bound made of rRNA and protein
Endoplasmic Reticulum A. Network of membrane-bound channels (tubules) - the interior of the tubules is segregated from the rest of the cytoplasm
B. Two types of ER rough and smooth both types are continuous with each other (and the nuclear envelope)
1. Rough ER a. ribosomes attached to outer surface b. protein synthesis (often for export)
2. Smooth ER a. lacks attached ribosomes b. lipid synthesis c. detoxification
Golgi Apparatus Processing and packaging plant
Golgi Apparatus Products packaged into vesicles for: insertion into the cell membrane secretion from cell (secretory vesicles) incorporation into lysosome
Lysosomes Can destroy harmful substances Can digest food particles Remove worn out organelles Must remain membrane-bound
Contain digestive enzymes 1. from ribosomes on RER 2. packaged in the Golgi
Apoptosis: programmed cell death - takes energy to maintain the integrity of lysosome membranes
Mitochondria Convert nutrient energy into ATP
Chloroplasts Have a double membrane (like mitochondria) 1. thylakoids 2. stroma
Chloroplasts and mitochondria share similar characteristics have their own circular DNA produced by division of existing ones
Cell Walls