Transcript Cells
Cells Chapter 7 • Cell consists of nucleus and cytoplasm. • In cytoplasm - organelles (“little organs”) • Cell membrane – boundary of cell. • Membrane thin but selectively permeable (allows certain materials to pass through but not others). http://www.geosciences.unl.edu/~dbennett/images/Cell_membrane.gif • Membrane has receptors that help receive messages (i.e. hormones) • Called phospholipid bilayer (composed of phospholipids); also various proteins in membrane. http://en.wikipedia.org/wiki/Cell_membrane • 1Endoplasmic Reticulum – increased surface area for reactions to take place. • ARough ER – Makes proteins (holds ribosomes) • BSmooth ER – Makes lipids. http://micro.magnet.fsu.edu/cells/endoplasmicreticulum/images/endoplasmicreticulumfigure1.jpg • 2Ribosomes – some attached to rough ER (bound); some scattered throughout cytoplasm (free). • Function - protein synthesis. http://www.brown.edu/Courses/BI0105_Miller/read/ribosomes/ribosomes.jpg • 3Golgi apparatus – proteins modified and packaged, then sent into cytoplasm. Modified protein http://web.mit.edu/esgbio/www/cb/org/golgi.gif • 4Mitochondria – cellular respiration. • Transform glucose into form of energy cell can use. http://micro.magnet.fsu.edu/cells/mitochondria/images/mitochondriafigure1.jpg • 5Lysosomes – contain enzymes that break down molecules of foreign particles (“garbage cans” of cell) http://micro.magnet.fsu.edu/cells/lysosomes/images/lysosomesfigure1.jpg • 6Centrosome – consists of 2 hollow cylinders (centrioles) - function in reproduction by separating chromosomes to new cells. http://www.nicerweb.com/doc/class/bio1151/Locked/media/ch06/06_22CentrosomeStructur.jpg • 7Cilia and 8flagella – extensions of cells; used for cell movement. • Flagella - longer and fewer. • Cilia - smaller and more numerous. http://pediatrics.med.unc.edu/div/infectdi/pcd/images/cilia.jpg Respiratory cilia http://discover.edventures.com/images/termlib/f/flagella/support.gif • 9Vacuoles – vesicles found in cell that have various functions. • AFood vacuole – breakdown of food. • BCentral vacuole – storage of waste. • CContractile vacuole – removal of water (osmoregulation). http://micro.magnet.fsu.edu/cells/plants/images/plantvacuolesfigure1.jpg • 10Microfilaments and microtubules – responsible for movement within cell (also responsible for structure) http://www.puc.edu/Faculty/Gilbert_Muth/art0053.jpg • 11Nucleus – center of cell. • Covered by nuclear envelope with pores to allow substances to pass through. • Contains 12nucleolus (ribosome production) and chromatin (loose DNA). http://micro.magnet.fsu.edu/cells/nucleus/images/nucleusfigure1.jpg Movement through cells • Passive does not require energy. • 4 passive movements (diffusion, facilitated diffusion, osmosis, filtration). • 1Diffusion – molecules or ions spread randomly from area of high concentration to area of low. http://epswww.unm.edu/coursinf/eps462/graphics/diffusion.gif • Particles will move until equilibrium reached (both sides equal). • Happens in lungs; O2, CO2 move by diffusion to be exchanged with air. • 2Facilitated diffusion - substance too large to cross cell membrane. • Special protein carrier allows substance to pass through membrane. http://w3.uokhsc.edu/human_physiology/presentation/facildiffani.gif • 3Osmosis - movement of water only from area of high to low. • If substance has higher [ ] of solute - hypertonic. • If lower [ ] - hypotonic. • Isotonic means they are even. http://www.biologycorner.com/resources/hypertonic.gif http://www.biologycorner.com/resources/hypotonic.gif http://www.biologycorner.com/resources/isotonic.gif • Filtration –molecules forced through membranes (result of blood pressure) • Active movement – requires energy. • Active transport – movement from area of low [ ] to high [ ]. • Requires pumps (a.k.a carrier molecules) to cross membrane. http://www.sp.uconn.edu/~terry/images/anim/antiport.gif • 2 processes – no crossing membrane. • 1Endocytosis – substances fuse with membrane, brought into cell. • 2Exocytosis – substances move out of cell (2 types). • APinocytosis – cell lets out small droplets of liquid. • BPhagocytosis – cell lets out solids. http://www.emc.maricopa.edu/faculty/farabee/BIOBK/endocytosis.gif http://www.biologie.uni-hamburg.de/b-online/library/biology107/bi107vc/fa99/terry/images/PhagoAnA.gif http://www.sirinet.net/~jgjohnso/endocytosissmall.jpg Cell Cycle • Life cycle of cell - cell cycle. • Interphase is the first part of the cell cycle. • It is the period of preparing for cell division. • Mitosis is the division of the nucleus and is divided into four phases. http://www.bioteach.ubc.ca/CellBiology/TheCellCycle/cellcycle.gif • Prophase - The chromosomes appear in nucleus from chromatin. Centrioles move to opposite sides of the nucleus. • Metaphase - The newly formed chromosomes line up midway between the centrioles and attach spindle fibers to the centrioles. Prophase http://sst.nsu.edu/bio110/exams/Prophase_Quiz.jpg http://everyschool.org/u/logan/cellreproductionx/jonesc/pictures/metaphase.jpg • Anaphase - The chromosomes begin to separate into chromatids. • Telophase - The chromatids are now separate in their new cells. Anaphase http://www.biologycorner.com/resources/anaphase.jpg Telophase http://iws.ccccd.edu/jbeck/CellDivision%20web/Telophase.JPG • After the nucleus has divided, cytokinesis (division of the cytoplasm) occurs. • This is the last phase of the cell cycle. • The two cells are now completely separated. http://img.sparknotes.com/figures/D/d756b5b73abe2974f3521a828791899f/cytokinesis.gif This will break and the cells will be separated. • Cell differentiation occurs to allow cells to become specialized.