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Tour of the cell: The Structure and Function (Organelles (Nucleus (is…
Tour of the cell: The Structure and Function
Types of Microscopes
Light Microscope
visible light is passed through the specimen and then through glass lenses
uses focused light and lenses to magnify a specimen
Electron Microscope
focuses a beam of electrons through the specimen or onto its surface
a microscope with high magnification and resolution employing electron beams using electron lenses
Scanning Electron Microscope
is especially useful for detailed study of the topography of a specimen
a specimen is scanned by a beam of electrons that are reflected to form an image
Transmission Electron Microscope
is used to study the internal structure of cells
an image is derived from electrons that have passed through the specimen in particular one in which the whole image is formed at once rather than by scanning
Cell Fractionation
useful technique for studying cell structure and functions
Takes cells apart and separates major organelles and other sub-cellular structures from one another
Centrifuge is the piece of equipment that is used for this task
spins test tubes and hold mixtures of disrupted cells at a series of increasing speeds
Enables researchers to prepare specific cell components in bulk and identify their functions, a task not usually possible with intact cells
Prokaryotic VS Eukaryotic Cells
Prokaryotic Cell
The DNA is concentrated in a region that is not membrane enclosed called the nucleoid
Lack nuclei and other membrane enclosed organelles
Eukaryotic Cell
DNA is in an organelle called the nucleus, which is bounded by a double membrane
have internal membranes that compartmentalize cellular functions
Organelles
Nucleus
is surrounded by nuclear envelope perforated by nuclear pores; nuclear envelope continuous with endoplasmic reticulum
Houses chromosomes which are made of chromatin ; contains nucleoli where ribosomal subunits are made; pores regulate entry and exit of materials
Ribosome
two subunits made of ribosomal RNa's and proteins; can be free in the cytosol or bound to the endoplasmic reticulum
in which protein synthesis occurs
Endoplasmic Reticulum
Has extensive network of membrane bounded tubules and sacs; membrane separates lumen from cytosol; continuous with nuclear envelope
consist of a smooth er and a rough er
smooth er: synthesizes lipids, metabolizes carbohydrates, calcium storage, detoxification of drugs and poison
consist of a rough er
aids in synthesis of secretory and other proteins on bound ribosomes; adds carbohydrates to proteins to make glycoproteins in order to produce a new membrane
Golgi Apparatus
composed of stacks of flattened membranous sacs; has polarity
modifies proteins, carbohydrates on proteins, and phospholipids; synthesizes many polyssacharides; sorting of golgi products which are then released in vesicles
Lysosome
composed of membranous sacs of hydrolytic enzymes
breakdown of ingested substances, cell macro-molecules and damaged organelles for recycling
Vacuole
large membrane bounded vesicles
Digestion, storage, waste disposal, water balance, cell growth, and protection