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Chapter 6: A Tour of the Cell - Coggle Diagram
Chapter 6: A Tour of the Cell
Microscopes and Cells
Microscopy
Light (LM) uses light and glass lenses to view the specimen
the lense refracts/bends the light in a way that the image is magnified
Scanning electron (SEM) uses a beam of electrons on the surface of the specimens (3D view)
is especially useful for the detailed study of the topography of a specimen
Transmission Electron (TEM) beam of electrons to view internal structures
cell fractionation takes cells apart and separates them from one another, which is done by a centrifuge
a centrifuge is a specimen that separates the specimen from density
Eukaryotic Cells
in eukaryotic cells most of the DNA is contained in an organelle called the nucleus
eukaryotic means true nucleus
this cell has cytoplasm, which refers to the region between the nucleus and the plasma membrane
these cells are larger than prokaryotic
contain membrane bound organelles
Prokaryotic Cells
in this cell the DNA is in a nucleoid (non-membrane enclosed region)
prokaryotic means before nucleus
they are smaller than eukaryotic cells
do not contain membrane-bound organelles
All Cells
ribosomes, to make proteins
genetic material (DNA)
cytoplasm/cystol
cell plasma/cell membrane
Functions of the Cell
Nucleus
the nucleus contains most of the genes in the eukaryotic cell
the nuclear envelope encloses the nucleus, separating its contents from the cytoplasm
nuclear lamina is a netlike array of protein filaments that lines the inner surface of the nuclear envelope and helps maintain the shape of the nucleus
this helps maintain the shape of the nucleus
within the nucleus are organized DNA units called chromosomes, which carry genetic information
chromatins are the complex of DNA and proteins that make up the chromosome
Ribosomes
ribosomes are RNA and proteins that carry out protein synthesis
they build proteins in two cytoplasmic regions: free ribosomes that are suspended in cytosol and bound ribosomes that are attached to the nuclear envelope
they are not membrane bound (not organelles)
cells with high rates of protein synthesis have larger number of ribosomes
most of the proteins made on free ribosomes function within the cytosol; examples are enzymes that catalyze the first steps of sugar breakdown
Golgi Apparatus
the golgi can be thought as a warehouse for receiving, sorting, and shipping and even manufacturing
here is where proteins are modified and stored and sent to other destinations
it consists of a group of associated, flattened membranous sacs—cisternae
the Golgi manufactures and refines its products in stages, with different cisternae containing unique teams of enzymes
Endomembrane System
Endoplasmic Rectilium
the endoplasmic rectilium (ER) is an extensive network of membranes that it accounts for more than half the total membrane in many eukaryotic cells
endoplasmic means within the membrane
the ER membrane separates the internal compartment of the ER, called the ER lumen (cavity) or cisternal space, from the cytosol
there are two different types of ER, smooth and rough
Smooth ER
smooth ER functions in diverse metabolic processes
this includes synthesis of lipids, metabolism of carbohydrates, detoxification of drugs and poisons, and storage of calcium ions
enzymes of the smooth ER are important in the synthesis of lipids, including oils, steroids, and new membrane phospholipids
other enzymes of the smooth ER help detoxify drugs and poisons, especially in liver cells
Rough ER
many cells secrete proteins that are produced by ribosomes attached to rough ER
as a polypeptide chain grows from a bound ribosome, the chain is threaded into the ER lumen through a pore formed by a protein complex in the ER membrane
most secretory proteins are glycoproteins
glycoproteins are proteins with one or more covalently attached carbs
after secretory proteins are formed, the ER membrane keeps them separate from proteins in the cytosol
rough ER grows by adding membrane proteins and phospholipids into its own membrane