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21 Cards in this Set
- Front
- Back
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Prokaryotic cells are characterized by having
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No nucleus
– DNA in an unbound region called the nucleoid – No membrane-bound organelles – Cytoplasm bound by the plasma membrane |
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Eukaryotic cells are characterized by having
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DNA in a nucleus that is bounded by a
membranous nuclear envelope – Membrane-bound organelles – Cytoplasm in the region between the plasma membrane and nucleus • Eukaryotic cells are generally much larger than |
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Ribosomes
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use the information from the DNA to make proteins
are particles made of ribosomal RNA and protein |
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Ribosomes carry out protein synthesis in two locations
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In the cytosol (free ribosomes)
– On the outside of the endoplasmic reticulum or the nuclear envelope (bound ribosomes |
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Components of the endomembrane system
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Nuclear envelope
– Endoplasmic reticulum – Golgi apparatus – Lysosomes – Vacuoles – Plasma membrane |
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endoplasmic reticulum (ER)
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ER membrane is continuous with the nuclear envelope
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two distinct regions of ER:
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Smooth ER, which lacks ribosomes
– Rough ER, with ribosomes studding its surface |
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Functions of Smooth ER
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Synthesizes lipids
– Metabolizes carbohydrates – Detoxifies poison – Stores calcium |
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Functions of Rough ER
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Has bound ribosomes, which secrete
glycoproteins (proteins covalently bonded to carbohydrates) – Distributes transport vesicles, proteins surrounded by membranes – Is a membrane factory for the cell |
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Peroxisomes
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are oxidative organelles
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Chloroplast structure includes:
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Thylakoids, membranous sacs, stacked to
form a granum – Stroma, the internal fluid |
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cytoskeleton
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organizes the cell’s structures and activities.
network of fibers extending throughout the cytoplasm |
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Roles of the Cytoskeleton
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It interacts with motor proteins to produce motility
The cytoskeleton helps to support the cell and maintain its shape |
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Three main types of fibers make up the
cytoskeleton: |
Microtubules
Microfilaments Intermediate filaments |
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Microtubules
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are the thickest of the three
components of the cytoskeleton Functions of microtubules: – Shaping the cell – Guiding movement of organelles – Separating chromosomes during cell division |
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Microfilaments
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also called actin filaments, are
the thinnest components |
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Intermediate filaments
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are fibers with
diameters in a middle range |
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Centrosomes and Centrioles
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In many cells, microtubules grow out from a
centrosome near the nucleus |
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Microfilaments (Actin Filaments)
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The structural role of microfilaments is to bear
tension, resisting pulling forces within the cell |
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Cytoplasmic streaming
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is a circular flow of
cytoplasm within cells |
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The Extracellular Matrix (ECM)
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The ECM is made up of glycoproteins such as
collagen, proteoglycans, and fibronectin • ECM proteins bind to receptor proteins in the plasma membrane called integrins |
