A Tour of the Cell

Cytology: science/study of cells Light microscopy Limited resolving power~ measure of clarity Electron microscopy •TEM~ electron beam to study cell ultrastructure (internal) •SEM~ electron beam to study cell surfaces Cell fractionation~ breaks apart cell to study organelles Ultracentrifuges~ separates organelles by density http://micro.magnet.fsu.edu/primer/java/electronmicroscopy/magnify1/index.html http://www.sumanasinc.com/webcontent/anisamples/microbiology/cellfractionation.html

Cell Types: Prokaryotic Bacteria Example: E.coli, Salmonella No organelles with membranes (ex: mitochondria) HAS: Nucleoid region: DNA concentration Circular Chromosomes Ribosomes: protein synthesis Plasma membrane Cytoplasm/cytosol https://www.google.com/search?q=necrotizing+fasciitis&safe=strict&espv=2&biw=1005&bih=610&source=lnms&tbm=isch&sa=X&ved=0ahUKEwjbhcHD4MPPAhWKOj4KHTF8Ao4Q_AUIBigB&dpr=1

Cell Types: Eukaryotic Generally more advanced than prokaryotes All cells in multi-cellular organisms are eukaryotic Nuclear membrane Numerous membrane-bound organelles http://www.studiodaily.com/main/technique/tprojects/6850.html

Cell Theory http://www.ucopenaccess.org/course/view.php?id=67 All living things are made of cells All cells come from pre-existing cells Cells are the basics units of structure and function for living organisms Key Playas: Robert Hooke Saw the first cell Coined the term “cell” Anton van Leeuwenhoek Saw the first “living” cell in pond water Theodor Schwann concluded all animals are made of cells Matthias Jakob Schleiden concluded all plants are made of cells Rudolf Virchow http://www.ucopenaccess.org/course/view.php?id=67 http://www.biologycorner.com/worksheets/cellrap.html

Cell size As cell size increases, the surface area to volume ratio decreases Rates of chemical exchange may then be inadequate for cell size Cell size, therefore, remains small

Nucleus Genetic material... •chromatin •chromosomes •nucleolus: ribosome synthesis (rRNA) Double membrane envelope with pores Protein synthesis (mRNA)

Ribosomes Site of protein synthesis 2 types: Free Bound Cytosol protein function in cell Bound endoplasmic reticulum membranes, organelles, and export

Endoplasmic reticulum (ER) Continuous with nuclear envelope Smooth ER no ribosomes synthesis of lipids metabolism of carbohydrates detoxification of drugs and poisons Rough ER with ribosomes synthesis of secretory proteins (glycoproteins), membrane production

Golgi apparatus ER products are modified, stored, and then shipped Cisternae: flattened membranous sacs cis face (receiving) trans face (shipping) Transport vesicles carry materials from GA http://bcs.whfreeman.com/thelifewire/content/chp04/0402002.html

Lysosomes Sac of hydrolytic enzymes digestion of macromolecules Apoptosis: programmed cell death caused by the rupture of lysosomes Autophagy: recycle cell’s own organic material Tay-Sachs disease~ lipid-digestion disorder http://highered.mcgraw-hill.com/sites/0072437316/student_view0/chapter5/animations.html#

Vacuoles Membrane-bound sacs (larger than vesicles) Food from phagocytosis Contractile vacuole (pump excess water) Central vacuole (storage in plants)

Mitochondria Quantity in cell correlated with metabolic activity Cellular respiration Production of ATP Contain own DNA Double membranous (phospholipid) cristae (inner folds) matrix intermembrane space;

Chloroplast Quantity in cell correlated with photosynthetic activity Photosynthesis Production of glucose Type of plastid Own DNA Double membranous thylakoids (flattened disks) grana (stacked thylakoids) stroma

Endosymbiosis Theory Believed that both mitochondria and chloroplasts were once independently living prokaryotes http://www.sumanasinc.com/webcontent/anisamples/nonmajorsbiology/organelles.html

Peroxisomes Stores hydrogen peroxide produced in cells Metabolism of fatty acids Detoxification of alcohol (liver) Hydrogen peroxide then converted to water by hydrogen peroxidase

The Cytoskeleton Fibrous network in cytoplasm Support, cell motility, biochemical regulation Microtubules: thickest tubulin protein shape, support, transport, chromosome separation Microfilaments: thinnest actin protein filaments motility, cell division, shape Intermediate filaments:middle diameter keratin; shape, nucleus anchorage http://micro.magnet.fsu.edu/moviegallery/pondscum/protozoa/amoeba/t1/amoeba04.html

Centrioles Centrioles: 9 sets of triplet microtubules in a ring used in cell replication only in animal cells

Cilia / Flagella Locomotive appendages Ultrastructure: 9 groups of 2 dynein protein tubules http://programs.northlandcollege.edu/biology/Biology1111/animations/flagellum.html http://micro.magnet.fsu.edu/moviegallery/pondscum/protozoa/paramecium/t1/paramecium08.html

Cell Membrane “The Bouncer” aka the Morturano A double layer made of phospholipids and proteins that surrounds the cell. Controls what enter and leaves the cell

Cell Wall / Junctions Cell wall: Plant cell: Plasmodesmata: not in animal cells protection, shape, regulation strong durable matrix of cellulose wood Plant cell: primary cell wall middle lamella: pectin (polysaccharide) holds cells together secondary cell wall Plasmodesmata: cell wall perforations water and solute passage in plants

Extracellular matrix (ECM) Glycoproteins: proteins covalently bonded to carbohydrate Collagen (50% of protein in human body) embedded in proteoglycan (another glycoprotein - 95% carbohydrate) Fibronectins bind to receptor proteins in plasma membrane called integrins (cell communication?)

Intracellular junctions PLANTS: Plasmodesmata ANIMALS: Tight junctions: fusion of neighboring cells prevents leakage between cells Desmosomes: riveted, anchoring junction strong sheets of cells Gap junctions: cytoplasmic channels allows passage of materials or current between cells