http://www.studiodaily.com/main /searchlist/6850.html Tour of the Cell 1 2011-2012
Cytology: science/study of cells To view cells: Light microscopy resolving power: measure of clarity Electron microscopy electron beam TEM: to study cell internal ultrastructure SEM: to study cell surfaces
Cytology: science/study of cells To isolate organelles: Cell fractionation: to separate major organelles Ultracentrifuge: cell fractionation; 130,000rpm or 1,000,000 g http://www.youtube.com/watch?v=8bnes4t1rdk
http://learn.genetics.utah.edu/content/begin/cells/scale/
Cell Size http://learn.genetics.utah.edu/content/begin/cells/scale/
Cell Size SA = 4 r 2 V = 4/3 r 3 Cell Radius 1 2 3 4 SA (r 2 ) 1 4 9 16 V (r 3 ) 1 8 27 64 SA/V (r 2 /r 3 ) 1 1/2 1/3 1/4 r Vand SA V > SA r SA/V
Cell Size As cell size increases, the SA to V ratio decreases Rates of chemical exchange may then be inadequate for cell size Cell size, therefore, remains small
Types of cells Prokaryote bacteria cells - no organelles Eukaryote animal cells - organelles Eukaryote plant cells http://www.yellowtang.org/animations/cell_features_v2.swf
Cell Types: Prokaryotic Nucleoid: DNA concentration No organelles with membranes Ribosomes: protein synthesis Plasma membrane: (all cells); semi-permeable Cytoplasm/cytosol (all cells)
Cell types: Eukaryotic Nucleus:membrane enclosed organelle containing chromosomes Membrane bound organelles of specialized form and function Generally larger than prokaryotic cells
Why organelles? Specialized structures specialized functions cilia or flagella for locomotion Containers partition cell into compartments create different local environments separate ph, or concentration of materials distinct & incompatible functions lysosome & its digestive enzymes Membranes as sites for chemical reactions unique combinations of lipids & proteins embedded enzymes & reaction centers chloroplasts & mitochondria mitochondria chloroplast Golgi ER
Cells must work to live! What jobs do cells have to do? make proteins proteins control every cell function make energy for daily life for growth 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!
Cells functions Building proteins read DNA instructions build proteins process proteins folding modifying removing amino acids adding other molecules e.g, making glycoproteins for cell membrane address & transport proteins
Building Proteins Organelles involved nucleus ribosomes endoplasmic reticulum (ER) Golgi apparatus vesicles The Protein Assembly Line nucleus ribosome ER Golgi apparatus vesicles
Nucleus Function protects DNA Structure nuclear envelope double membrane nuclear pores nucleolus DNA histone protein membrane fused in spots to create pores allows large macromolecules to pass through What kind of molecules need to pass through? chromosome nuclear pore nuclear envelope
1 DNA http://www.youtube.com/watch?v=4jtmoza IvS0&feature=related nuclear membrane http://www.youtube.com/watch?v=i9arijwyzhi production of mrna from DNA in nucleus Nucleus mrna http://www.dnalc.org/resources/3d/12-transcription-basic.html 2 nuclear pore mrna travels from nucleus to ribosome in cytoplasm through nuclear pore http://www.dnalc.org/view/15481-translation-rna-toprotein-3d-animation-with-no-audio.html mrna small ribosomal subunit large ribosomal subunit cytoplasm
Nucleolus Function 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
Ribosomes Function protein production Structure rrna & protein 2 subunits combine Ribosomes Rough ER large subunit small subunit 0.08mm Smooth ER
Types of Ribosomes Free ribosomes suspended in cytosol synthesize proteins that function in cytosol Bound ribosomes attached to endoplasmic reticulum synthesize proteins for export or for membranes membrane proteins
Endoplasmic Reticulum Function processes proteins manufactures membranes synthesis & hydrolysis of many compounds Structure membrane connected to nuclear envelope & extends throughout cell http://www.youtube.com/watch?v=puy_em5dxmc
Types of ER rough smooth
Smooth ER function Membrane production Many metabolic processes synthesis synthesize lipids oils, phospholipids, steroids & sex hormones hydrolysis hydrolyze glycogen into glucose in liver detoxify drugs & poisons in liver ex. alcohol & barbiturates
Membrane Factory Build new membrane synthesize phospholipids builds membranes ER membrane expands bud off & transfer to other parts of cell that need membranes
Rough ER function Produce proteins for export out of cell protein secreting cells packaged into transport vesicles 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 Which cells have lots of Golgi? finishes, sorts, tags & ships cell products like UPS shipping department ships products in vesicles membrane sacs UPS trucks secretory vesicles transport vesicles
Golgi Apparatus http://www.youtube.com/watch?v=rvfvrgk0mfa http://www.dnatube.com/video/1594/protein-modification-golgi
Vesicle transport protein vesicle budding from rough ER migrating transport vesicle fusion of vesicle with Golgi apparatus ribosome
nucleus DNA endoplasmic reticulum protein on its way! TO: RNA vesicle TO: ribosomes TO: vesicle Making Proteins Regents Biology protein Golgi apparatus TO: finished protein
Putting it together nucleus nuclear pore cell membrane rough ER making proteins protein secreted ribosome vesicle proteins smooth ER cytoplasm transport vesicle Golgi apparatus
Putting it together making proteins
Tour of the Cell 2 2007-
Food & water storage food vacuoles plant cells central vacuole animal cells contractile vacuole
Lysosomes Function little stomach of the cell digests macromolecules clean up crew of the cell cleans up broken down organelles Structure vesicles of digestive enzymes Where old organelles go to die! synthesized by rer, transferred to Golgi only in animal cells
Lysosomes 1960 1974 white blood cells attack & destroy invaders = digest them in lysosomes 1974 Nobel prize: Christian de Duve Lysosomes discovery in 1960s
Cellular digestion Lysosomes fuse with food vacuoles polymers digested into monomers pass to cytosol to become nutrients of cell vacuole lyso = breaking things apart some = body
Lysosomal enzymes Lysosomal enzymes work best at ph 5 organelle creates custom ph how? proteins in lysosomal membrane pump H + ions from the cytosol into lysosome why? enzymes are very sensitive to ph why? enzymes are proteins ph affects structure why evolve digestive enzymes which function at ph different from cytosol? digestive enzymes won t function well if some leak into cytosol = don t want to digest yourself!
When things go bad Diseases of lysosomes are often fatal digestive enzyme not working in lysosome picks up biomolecules, but can t digest one lysosomes fill up with undigested material grow larger & larger until disrupts cell & organ function lysosomal storage diseases more than 40 known diseases example: Tay-Sachs disease build up undigested fat in brain cells
Lysosomal storage diseases Lipids Gaucher s disease Niemann-Pick disease Tay Sachs Glycogen & other polysaccharides Farber disease Krabbe disease Proteins Schindler s disease
Lysosomal storage disease Hepatosplenomegaly courtesy of The National MPS Society, Inc. http://www.lysosomallearning.co m/healthcare/about/lsd_hc_abt_ niemann.asp