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Chapter 6. Cells. 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).
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Chapter 6 Cells
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.gifhttp://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.
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.jpghttp://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.jpghttp://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.jpghttp://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.jpghttp://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.jpghttp://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.jpghttp://pediatrics.med.unc.edu/div/infectdi/pcd/images/cilia.jpg Respiratory cilia
http://discover.edventures.com/images/termlib/f/flagella/support.gifhttp://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.jpghttp://micro.magnet.fsu.edu/cells/plants/images/plantvacuolesfigure1.jpg
10Microfilaments and microtubules – responsible for movement within cell (also responsible for structure)
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.jpghttp://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.gifhttp://w3.uokhsc.edu/human_physiology/presentation/facildiffani.gif
Cells in Solutions with Water • Hypertonic- Greater concentration of dissolved particles than water. Cell will shrink as water moves into solution • Isotonic- Equal concentration of dissolved particles and water. Cell remains the same size. • Hypotonic- Lower concentration of dissolved particles than water. Cell will swell as water moves into the cell from the solution.
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.
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.gifhttp://www.emc.maricopa.edu/faculty/farabee/BIOBK/endocytosis.gif
http://www.biologie.uni-hamburg.de/b-online/library/biology107/bi107vc/fa99/terry/images/PhagoAnA.gifhttp://www.biologie.uni-hamburg.de/b-online/library/biology107/bi107vc/fa99/terry/images/PhagoAnA.gif
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.gifhttp://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