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cells02-2009 - Lectures 2-3 Cell History Study Study of...

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Unformatted text preview: Lectures 2-3 Cell History Study Study of cells old old theories spontaneous spontaneous generation?? vitalism?? vitalism?? ECB3 1-5 Discovery of Cells • Early important people o o Robert Hooke (1665) – called chambers inside cork “cells” Antonie van Leeuwenhoek (1674) – discovery of protozoa and bacteria • Important techniques –1910 -1960: biochemistry –30’s - 40’s: genetics –50’s+: electron microscopy correlation of structure and function “new” “new” theories evolution evolution cell cell theory Schleiden & Schwann (1830’s) All living things consist of cells; all cells come from other cells. A Sense of Scale Metric System It’s essential that you are comfortable using the metric system. These prefixes will be used frequently this semester and you must be able to convert from one to another: 01_06_What can we see.jpg can we see • centi- (c_; 10-2) 10 • milli- (m_; 10-3) • micro- (μ_; 10-6) • nano- (n_; 10-9) ECB3 1-6 http://micro.magnet.fsu.edu/primer/java/scienceopticsu/powersof10/index.html Measurements will be distance (meters; m), mass (grams; g) or fluid volumes (liters; L). Light Microscope Transmission Electron Microscope A beam of electrons passes through a thin slice of a sample. The The very short wavelength of the electron, compared to light, gives a much higher magnification range (up to 1,000,000X) to see structures as small as 0.2 nm. Fluorescent microscope ECB3 P1-1 Bio 106 Fall 2009 Professor Owen 1 Lectures 2-3 Definition of a Cell Basic Basic unit of all living organisms. Enclosed Enclosed by a membrane. Controlled by genes (DNA) to produce Controlled proteins that build specific structures and carry out specific functions. Has Has cellular processes that require energy. What makes a cell a cell? • Membrane bound • Degrees of internal order • Low = Procaryotes • High = Eucaryotic (internal membranes) Outer membrane = plasma membrane This is the site of interactions between the inside and outside of the cell Compare Prokaryotic and Cells Cellular Functions Procaryotic Plasma Membrane genetic genetic processes energy energy processes secretory secretory functions digestive digestive processes nutrition nutrition uptake Eucaryotic Organelles nucleus mitochondria ER/Golgi lysosome plasma membrane Eukaryotic Cells Plants, animals, and fungi •Membrane bound nucleus •Membrane bound compartments called organelles Evolution of Living Cells ~ 1.5 billion years ~ 3.8 billion years Modified from Cooper 1.7 ECB3 1-29 Bio 106 Fall 2009 Professor Owen 2 Lectures 2-3 Nucleus Genetic Genetic processes Has a double membrane with pores. pores. Contains one or more nucleoli, the site of ribosome synthesis ECB3 1-15 A. A. B. C. D. E. Speculate – what is the function of the pores in the nuclear membrane? To block movement of molecules To allow free movement of molecule entry & exit To regulate movement of molecule entry & exit Imperfections in formation of membrane For attachment of rER to membrane A. A. B. C. D. E. Why is a nuclear transport regulating system important for cell function? ?? ?? ?? ?? ?? A. A. B. C. D. E. Why is a nuclear transport regulating system important for cell function? To make the cell happy To concentrate molecules to efficiently carry out their functions To limit entry of non-essential nonmolecules To concentrate molecules To minimize energy loss Mitochondrion (plural = mitochondria) A Symbiotic Relationship? Energy processes “Powerhouse of the cell” Synthesis of ATP energy by oxidative phosphorylation Double membrane (inner = cristae) ECB3 1-18 Theory: Lynn Margolis ECB3 1-19 Bio 106 Fall 2009 Professor Owen 3 Lectures 2-3 Chloroplast Energy processes in a plant (in addition to mitochondria). Site of photosynthesis (chlorophyll). Symbiosis Evolution? ECB2 1-20 ECB3 1-21 Endoplasmic reticulum • Usually the largest membrane • For synthesis and transport of lipids and membranemembrane-associated proteins rER rER = protein synthesis sER sER = lipid synthesis Golgi apparatus Traffic control center • System of stacked, membrane bounded flattened sacs that modify sort and modify, sort, and secrete secrete large molecules • For molecule delivery within the cell or secretion outside the cell. ECB3 1-23 ECB3 1-22 Lysosomes Small, Small, irregularly shaped organelles for intracellular digestion Breaks Breaks down unneeded unneeded molecules for for recycling or excretion. Cytosol ECB2 1-8 A concentrated aqueous gel of large and small molecules (cytoplasm = cytosol + organelles). ECB3 1-24 Bio 106 Fall 2009 Professor Owen 4 Lectures 2-3 Cytoskeleton • The cell skeleton • Arrays of protein filaments • Gives the cell its shape and the basis for directed cellular movements Cytoskeleton actin microfilaments microtubules intermediate filaments actin cytoskeleton ECB3 1-27 MBOC3 1-26 Cell Contents General Specific (HeLa cell) • 70% water • 15 pg DNA • 7% salts, lipids, • 30 pg RNA pg RNA amino acids, • 300 pg protein nucleotides (5 (5 x 109 molecules) • 23% macromolecules • 4 x 106 ribosomes • dry weight = 400 pg From ECB2 Make sure you understand the metric system! Information Flow Proteins = major functioning unit of the cell • 3-D transformation of DNA • Cell compartments contain specific proteins Information Flow DNA RNA Protein Division between the nucleus and cytoplasm: DNA nucleus RNA protein cytoplasm RNA = shuttle between nucleus and cytoplasm Bio 106 Fall 2009 Professor Owen 5 Lectures 2-3 Information Flow transcription translation “Central Dogma” DNA RNA Protein The Central Dogma ECB2 7-1 DNA in the nucleus is packaged into chromosomes All of the information to code for a human being is contained on 46 chromosomes Chromosomes are in pairs 19,599 confirmed proteincoding genes “spell” for a human being Genes are pieces of DNA in chromosomes Genes code for proteins, and proteins do all the work in cells. Structural Metabolic Transporters Regulators Defenders Communicators Bio 106 Fall 2009 Professor Owen 6 ...
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