Tour of the Cell 1 Types of cells Prokaryote bacteria cells - no organelles - organelles Eukaryote animal cells Eukaryote plant cells Why organelles? Specialized structures u specialized functions cilia or flagella for locomotion Containers u partition cell into compartments u create different local environments separate ph, or concentration of materials u distinct & incompatible functions lysosome & its digestive enzymes Membranes as sites for chemical reactions u unique combinations of lipids & proteins u embedded enzymes & reaction centers chloroplasts & mitochondria mitochondria chloroplast Golgi ER 1
Cells gotta work to live! What jobs do cells have to do? u make proteins proteins control every cell function u make usable energy for daily life for growth u make more cells growth repair renewal Building Proteins 2007-2008 Proteins do all the work! proteins DNA organism cells Repeat after me Proteins do all the work! 2
Cells functions Building proteins u read DNA instructions u build proteins u process proteins folding modifying w removing amino acids w adding other molecules n e.g, making glycoproteins for cell membrane u address & transport proteins Building Proteins Organelles involved u nucleus u ribosomes u endoplasmic reticulum (ER) u Golgi apparatus u s nucleus ribosome ER The Protein Assembly Line Golgi apparatus s Nucleus Function u protects DNA Structure What kind of molecules need to pass through? w allows large macromolecules to pass through nuclear pores nucleolus DNA histone protein u nuclear envelope double membrane membrane fused in spots to create pores chromosome nuclear pore nuclear envelope 3
1 nuclear membrane DNA production of mrna from DNA in nucleus Nucleus mrna mrna travels from nucleus to ribosome in cytoplasm through nuclear pore 2 nuclear pore mrna small ribosomal subunit large ribosomal subunit cytoplasm Nucleolus Function u ribosome production build ribosome subunits from rrna & proteins exit through nuclear pores to cytoplasm & combine to form functional ribosomes large subunit small subunit rrna & proteins ribosome nucleolus 4
Ribosomes Function u protein production Structure u rrna & protein u 2 subunits combine Ribosomes Rough ER large subunit small subunit 0.08µm Smooth ER Types of Ribosomes Free ribosomes u suspended in cytosol u synthesize proteins that function in cytosol Bound ribosomes u attached to endoplasmic reticulum u synthesize proteins for export or for membranes membrane proteins Endoplasmic Reticulum Function u processes proteins u manufactures membranes u synthesis & hydrolysis of many compounds Structure u membrane connected to nuclear envelope & extends throughout cell 5
Types of ER rough smooth Smooth ER function Membrane production Many metabolic processes u synthesis synthesize lipids w oils, phospholipids, steroids & sex hormones u hydrolysis hydrolyze glycogen into glucose w in liver detoxify drugs & poisons w in liver w ex. alcohol & barbiturates Membrane Factory Build new membrane u synthesize phospholipids builds membranes u ER membrane expands bud off & transfer to other parts of cell that need membranes 6
Rough ER function Produce proteins for export out of cell u protein secreting cells u packaged into transport s for export Which cells have lot of rough ER? Synthesizing proteins cisternal space polypeptide signal sequence mrna ribosome ribosome membrane of endoplasmic reticulum cytoplasm Golgi Apparatus Function u finishes, sorts, tags & ships cell products like UPS shipping department u ships products in s membrane sacs Which cells UPS trucks have lots of Golgi? secretory s transport s 7
Golgi Apparatus Vesicle transport protein budding from rough ER migrating transport fusion of with Golgi apparatus ribosome nucleus DNA endoplasmic reticulum protein on its way! TO: RNA TO: ribosomes TO: Making Proteins Regents Biology protein Golgi apparatus TO: finished protein 8
Putting it together nucleus nuclear pore cell membrane rough ER Making proteins protein secreted ribosome proteins smooth ER cytoplasm transport Golgi apparatus 9
Any Questions!! 2007-2008 10