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26 Cards in this Set
- Front
- Back
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Plasma Membrane-
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- regulates the passage of materials into and out of cell
- phospholipid bilayer |
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Fluid Mosaic Model
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- plasma membrane consists of phospholipid bilary with hydrophilic and hydrophobic regions
- FLUIDITY can be changed by: 1) Number of UNsaturated FA hydrocarbon tails (kinks) 2) amount of cholesterol present |
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Cytosol
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fluid portion of cytoplasm with nutirents, free proteins and other solutes
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KEY DIFFERENCE between EUKARYOTES AND PROK
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- euk have membrane bound organelles (ie. nucleus, lysosomes)
but prok do have a nuclear membrane |
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Mem bound organelles
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allow euk cells to compartmentalize activities in different parts of the cell (ie. ATP production and consumption) and control these activities independently
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Nucleolus
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site of rRNA synthesis and is not surrounded by a membrane
- ribsomal subunits exported from nucleus to cytoplasm after being aseembled here. |
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Mitochondria
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-outer membrane phospholipid bilary
-intermembrane space - high H_ concentration - inner membrane phospholipid bilayer = cristae = houses proteins of ETC -matrix: site of Citric Acid/Kreb's; low H+ concentration **H+ move from high (intermem space) to low concentration (matrix) **WITHIN CELL - mito function SEMIAUTONOMOUSLY **IMPT FOR ENERGY PRODUCTION - needs 02 to function! |
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Endosymbiotic hypothesis
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- GENOME AND RIBOSOMES more similar to prok
-mitochondria developed from early prok cells but began a symbiotic relationship with euk ancestors 1) mitochondria provides energy 2) euk host cell provides nutrients and protection from exterior environment -SEMIAUTONOMOUS FUNCTION WITHIN CELL - 1. contain own circular DNA & ribosomes 2. capable of producing some proteins |
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Mitochondrial Inheritance
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- Zygote receives ALL ORGANELLES from mom so any mito DNA a person has is IDENTICAL to mom.
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Ribosomes
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- made in nucleolus and exported to cytoplasm to help with protein synthesis
- Large and small subunits of RNA AND PROTEINS - smaller ribosomes in Prok than euk. FREE: make proteins for cytoplasm ROUGH ER: proteins for insertion into a membrane or secretion outside of cell |
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ER
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- some portions of ER lumen continuous with nuclear envelope
1) ROUGH: ribosomes on surface for protein synthesis - proteins made on ribosomes on Rough ER surface transported to lumen during synthesis. - small regions of ER bud off to form membrane bound vesicles containing new proteins - ship vesicles to Golgi 2) SMOOTH - no ribosomes - involved in lipid synthesis (ie. steroids!) -detox drugs and poisons - glucose production - Ca2+ ion concentration - Steroid production -convert cholesterol to various steroids |
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Golgi
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between ER and plasma membrane
- CIS: receiving end from ER lumen - TRANS - MAKES LYSOSOMES **modify proteins and sort them out to be shipped off: ie) glycosylation - add sugar groups to proteins **more prominent and numerous in cells synthesising and secreting many substances: plasma B cells, the antibody-secreting cells of the immune system |
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Lysosomes
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made from GOLGI
-hydrolytic enzymes in intracellular digestion that break down proteins, carbs, nucleic acids. - H20 is a reactant!!! - slightly acidic ph5 inside separated by membrane UNICELLULAR organisms: impt for digestion of food VS MULTICELLULAR : important for degradation of foreign particles like bacteria and damaged cells |
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Peroxisomes
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oxidative enzymes catalyze rxns in which MAKE H2O2 (hydrogen peroxide) and degrade them
- break down fats - detox in liver (ie. alcohol) **EXAMPLE OF IMPT. COMPARTAMENTILZATION OF ACTIVITY - peroxides dangerous to macromolecules like DNA if free in cytoplasm! |
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Cytoskeleton
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network of specialized proteins that provides the framework for cell shape, is impt in cell movement, and movement of organelles witihin cell
PROTEIN FILAMENTS: 1) MICROFILAMENTS - made up of intertwined strands of ACTIN - produce contracting force in muscle - cytoplasmic streaming (ameoba-like movement) - phagocytosis and microvilli movement 2) INTERMEDIATE FILAMENTS - for structural support; made of thick fibrous protein coiled into a cable 3) MICROTUBULES - made up of glagellum and cilium = globule tubulin protein - 9+2 arrangement in cilia or flagellum= axoneme - tubules connected to each other by dyenin. - POLARIZED - positive and negative end. negative end attaches to MTOC - centrosome. **CENTRIOLES help in production of flagella and cilia but are not necessary for microtubule production |
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Cilia
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- made up of axoneme (9+2 microtubules _ dyenin)
- move in WHIP like fashion -line respiratory tract - move particles up cell surface or propel a cell wtihin a fluid |
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Flagella
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- made up of axoneme (9+2 microtubules _ dyenin)
- similar structure to cilia but larger in structure -move in WAVE lke fashion ie) sperm |
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Tight junction
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total barrier to transport and diffusion
- binds cells tightly that no material can pass ie) intestine |
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Desmosomes
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anchoring junction
- TIGHTEST hold of all - Found in cells subject to mechanical stress & often with tight juncitons (ie. skin) |
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GAP Junction
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direct connection between cytoplasm of one cell and cytoplasm of another via CHANNELS = CONNEXINS
ie) heart - allows rhytmic coordinate contracton of muscle |
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Transport across membrane
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1. PINOCYTOSIS
- nonselective - most cells - ECF fluid engulfed by small invaginations of cell membrane 2. PHAGOCYTOSIS - -large particles (ie - WBC's) - specific activation via binding of proteins on particulate matter to protein receptors on Phagocytic cell -> Cell membrane ENGULFS particulate matter-> PHAGOSOME - few cells 3. RECEPTOR MEDIATED ENDOCYTOSIS: - SPECIFIC uptake of macromolecules - ligand binds to receptor protein on cell membrane and then is moved to a CLATHRIN COATED PIT. - pit invaginates to form COATED VESICLE |
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Phagocytosis vs. Receptor Mediated Endocytosis
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Phagocytosis - ligands act as signals to initiate phagocytosis of OTHER particles
vs. Receptor mediated - ligands are meant to be absorbed! |
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Secretory vesicles
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contain enzymes, growth factors or ECM components
- release contents through EXOCYTOSIS: a way to contribute to membrane 1. Constitutive Secretion - vesicles continuosly released from cell 2. Regulated Secretion - release aaccording to a stimuli (chemical or electricla) ie) Insulin - activated WITHIN vesicle. |
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Microtubules
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MICROTUBULES - made up of glagellum and cilium = globule tubulin protein
ie) in CILIA/EUK FLAGELLIN - 9+2 arrangement in cilia or flagellum= axoneme - tubules connected to each other by dyenin. ie) found in MITOTIC SPINDLE - POLARIZED - positive and negative end. negative end attaches to MTOC - centrosome. **CENTRIOLES help in production of flagella and cilia but are not necessary for microtubule production |
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Glycocalyx
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on outside of cells (analgous to plant cell wall or bacterial cell wall)
- separates cell membrane from ECM - part of it is made from same material as the ECM - invovleved in cell-cell recognition, adhesion, cell surface protection and permeability. - Contact inhibition - cancer cell shave abnromal glycocalyx so continually grows. - microbes recognize glycocalyx and infect cell |
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Euk. Flagella vs. Prok Flagella
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EUK:
made from 9+2 micortubule config (axoneme) - uses ATP to power movememnt -whip like movement PROK: -pade up of thin strand single protein called flagellin - rotate - driven by proton gradient |
