Chapter 6 � A Tour of the Cell

Chapter 6 � A Tour of the Cell - Chapter 6 A Tour of...

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Microscopy o Light microscope (LM) – visible light is passed through the specimen and then through glass lenses Magnification – ratio of an object’s image size to its real size Resolution – the measure of the clarit of the image Contrast – accentuates differences in parts of the sample Organelles – membrane enclosed compartements – too small to be seen with the light microscope o Electron microscope (EM) – focuses a beam of electrons through the specimen or onto its surface Resolution is inversely related to the wavelength of the radiation of a microscope uses for imaging Ultrastructure – the cellular anatomy revealed by an electron microscope o Scanning electron microscope (SEM) – useful for detailed study of the surface of a specimen Electron beam scans the surface of the sample Coated in a thin film of gold o Transmission electron microscope (TEM) – used to study the internal ultrastructure of cells Aims electron beam through a very thin section of the specimin Enhancing the eletron density of some parts of the cell Cytology – study of cell structure o Biochemistry – the study of the molecules and chemical process of cells Cell Fractionation – useful technique for studying cell structure and function o Takes cells apart and separates the major organelles and other subcellular structures from one another. o Centrifuge – spoins test tubes holding mixtures of disrupted cells at various speeds Causes a fracton of the cell components to settle at the bottom of the tube o Ultracentrifuges – most powerful centrifuges Eukaryotic cells have internal membranes that compartmentalize functions Prokaryotic and Eukaryotic Cells o Bacteria and Archaea – Prokaryotic o Protists, fungi, animals and plants – eukaryotic Eukaryotic cells fs. Prokaryotic cells o All bound by a selective plasma membrance The membrane encloses a semifluid, jellylike substance called cytosol o All have chromosomes – carry genes o All cells have ribosomes – tiny complexes that make proteins according to instructions from genes o In eukaryotic cell – DNA is found in an organelle called the nucleus Bound by a double membrane o Prokaryotic cell – DNA is concentrated in a region that is not membrane enclosed called the nucleoid Interor of a prokaryotic cell is – cytoplasm o Also region between the nucleus and eh plasma membrane of a eukaryotic cell Ribosomes o Made up of ribosomal RNA and protein
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This note was uploaded on 10/07/2010 for the course HELLO IDK taught by Professor Armand during the Spring '10 term at Barber-Scotia.

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Chapter 6 � A Tour of the Cell - Chapter 6 A Tour of...

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