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IUB BIOL-L 112 - Introduction to Cell Structure and Function

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MICROSCOPYMicroscopy provides enlargement and resolutionLight MicroscopeEnlargement provided by objective lens and ocular glass and lensesIllumination provided by lightTransmission Electron Microscope (TEM)Illumination provided by electron beam – much shorter wavelengthVery high resolutionScanning Electron Microscope (SEM)Electrons do not pass through specimenLower resolution than TEM3D imageTWO MAJOR CATEGORIES OF CELLSProkaryotic cells – Bacteria and ArchaeaSimple smallerEukaryotic Cells – protists, plants, fungi and animalsCytoskeleton – microtubules, intermediate filaments, microfilamentsPLASMA MEMBRANEA Fluid Mosaic of Lipids and ProteinsMembranes composed mostly ofLipids - The lipids are phospholipids (phospholipid bilayer)Proteins – Regulate traffic across the membranes and perform other functions.Plasma membrane is a fluid mosaicFluid – Molecules move freely past one anotherMosaic – Diversity of proteins in the membraneNUCLEUSNuclear envelope: Double membrane separating nucleus andcytoplasmPores: Allows material to move between the nucleus and cytoplasm selectivelyNucleolus: In nucleus where ribosome precursors are assembled (rRNA and rProteins)Chromatin: DNA molecules and associated proteins that form fibersNucleosome: Unit of DNA packing (DNA wraps around 4 pairs of histone)Each long Chromatin fiber constitutes one chromosomeThe number of chromosomes in a cell depends on the speciesRIBOSOMESProtein making machines of the cellPartially assembled in the nucleolus and totally in the cytoplasmHOW DNA DIRECTS PROTEIN PRODUCTIONDNA programs protein production in the cytoplasm by transferring its coded information into messenger RNA (mRNA)Messenger RNA exits the nucleus through pores in the nuclear envelopesA ribosome moves along the mRNA, translating the genetic message into a protein with a specific amino acid sequence.ROUGH ERRibosomes that stud the outside of the portion of the ER membrane make the ER “rough”. Produce membrane proteins and secretory proteinsSome products manufactured by rough ER are dispatched to other locations in the cell by transport vesicles, sacs made of membranes that bud off from the rough ERSMOOTH ERLacks surface ribosomes produce lipids, including steroids and helps liver cells detoxifyBIOl-L 112 1st Edition Lecture 4Outline of Last Lecture I. Proteins a. Make up of a protein b. Structures c. DenaturationII. Nucleic Acids a. Make up of Nucleic Acids b. Dehydration Reactions Outline of Current Lecture III. Microscopy a. Light Microscope b. Transmission Electron Microscope c. Scanning Electron Microscope IV. Two Major Categories of Cells a. Prokaryotic Cells b. Eukaryotic Cells V. Plasma Membrane a. Fluid Mosaic VI. Nucleus a. Nuclear Envelope b. Pores c. Nucleolusd. Chromatin e. Nucleosome VII. RibosomesVIII. How DNA Direct Protein Production IX. Rough ER X. Smooth ER Current LectureThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute. MICROSCOPY Microscopy provides enlargement and resolution Light Microscope Enlargement provided by objective lens and ocular glass and lenses Illumination provided by light Transmission Electron Microscope (TEM) Illumination provided by electron beam – much shorter wavelength Very high resolution Scanning Electron Microscope (SEM) Electrons do not pass through specimen Lower resolution than TEM 3D image  TWO MAJOR CATEGORIES OF CELLS Prokaryotic cells – Bacteria and ArchaeaSimple smaller Eukaryotic Cells – protists, plants, fungi and animals Cytoskeleton – microtubules, intermediate filaments, microfilamentsPLASMA MEMBRANEA Fluid Mosaic of Lipids and Proteins Membranes composed mostly of Lipids - The lipids are phospholipids (phospholipid bilayer)Proteins – Regulate traffic across the membranes and perform other functions.Plasma membrane is a fluid mosaic Fluid – Molecules move freely past one another Mosaic – Diversity of proteins in the membrane  NUCLEUSNuclear envelope: Double membrane separating nucleus andcytoplasm Pores: Allows material to move between the nucleus and cytoplasm selectively Nucleolus: In nucleus where ribosome precursors are assembled (rRNA and rProteins) Chromatin: DNA molecules and associated proteins that form fibersNucleosome: Unit of DNA packing (DNA wraps around 4 pairs of histone) Each long Chromatin fiber constitutes one chromosome The number of chromosomes in a cell depends on the species RIBOSOMES Protein making machines of the cell Partially assembled in the nucleolus and totally in the cytoplasm HOW DNA DIRECTS PROTEIN PRODUCTION DNA programs protein production in the cytoplasm by transferring its coded information into messenger RNA (mRNA)Messenger RNA exits the nucleus through pores in the nuclear envelopes A ribosome moves along the mRNA, translating the genetic message into a protein with a specific amino acid sequence. ROUGH ER Ribosomes that stud the outside of the portion of the ER membrane make the ER “rough”. Produce membrane proteins and secretory proteins Some products manufactured by rough ER are dispatched to other locations in the cell by transport vesicles, sacs made of membranes that bud off from the rough ER SMOOTH ER Lacks surface ribosomes produce lipids, including steroids and helps liver cells


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IUB BIOL-L 112 - Introduction to Cell Structure and Function

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