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midterm guides - GENERAL FEATURES OF CELLS CHAPTER 4 Cell...

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Unformatted text preview: GENERAL FEATURES OF CELLS CHAPTER 4 Cell theory 1. All living things are composed of one or more cells 2. Cells are the smallest units of living organisms 3. New cells come only from pre-existing cells by cell division Microscopy Magnification Ratio between the size of an image produced by a microscope and its actual size Resolution Ability to observe two adjacent objects as distinct from one another Contrast Can be enhanced using dyes Electron microscopes Transmission electron microscopy (TEM) Thin slices stained with heavy metals Some electrons are scattered while others pass through to form an image Scanning electron microscopy (SEM) Sample coated with heavy metal Beam scans surface to make 3D image Prokaryotic cells Simple cell structure Lack a membrane-enclosed nucleus 2 categories- bacteria and archaea Both small Bacteria- abundant, most not harmful Archaea- less common, often found in extreme environments Typical bacterial cell Plasma membrane- barrier Cytoplasm- contained inside plasma membrane Nucleoid- region where genetic material found Ribosomes- involved in protein synthesis Eukaryotic cells DNA housed inside nucleus Eukaryotic cells exhibit compartmentalization Organelle- sub cellular structure or membrane-bounded compartment with its own unique structure and function Shape, size, and organization of cells vary considerably among different species and even among different cell types of the same species The Proteome Determines the Characteristics of a Cell How does a single organism produce different types of cells? Identical DNA in different cells but different proteomes The proteome of a cell determines its structure and function Gene regulation, amount of protein, amino acid sequence of a particular protein and protein modification can influence a cell’s proteome Proteomes in healthy cells are different from the proteomes of cancerous cells Cytosol Region of a eukaryotic cell that is outside the cell organelles but inside the plasma membrane Cytoplasm includes everything inside the plasma membrane Cytosol, the endomembrane system and the semiautonomous organelles Metabolism Cytosol is central coordinating region for many metabolic activities of eukaryotic cells Catabolism- breakdown of a molecule into smaller components Anabolism- synthesis of cellular molecules and macromolecules Cytoskeleton Network of three different types of protein filaments Microtubules Dynamic instability Centrosome or microtubule-organizing center in animals Intermediate filaments Tend to be more stable than microtubules and actin filaments, which readily polymerize and depolymerize Actin filaments Also known as microfilaments Motor Proteins Category of cellular proteins that use ATP as a source of energy to promote movement...
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This note was uploaded on 04/24/2008 for the course CELL 101 taught by Professor Burdsal during the Spring '08 term at Tulane.

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midterm guides - GENERAL FEATURES OF CELLS CHAPTER 4 Cell...

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