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32 Cards in this Set
- Front
- Back
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How many cells are in the human body? How big are they? |
60.000 billions, 4-120 µm. |
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What are the signs of a living cell? |
Own metabolism |
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What is the purpose of intracellular surface membrane? |
It covers subcellular structures. |
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What is the purpose of a plasmatic surface membrane? |
It covers the surface of each cell. |
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What are surface membranes made of? |
Phospholipid bilayer (double phospholipid layer). |
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What are the functions of a plasmatic surface membrane? Name three. |
Semipermeability, division, protection, integrative roles, ion transportation, enzyme source, electric charge storage etc. |
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Explain hydrophylic heads. |
Made of water-soluble phosphates, positively charged and directed to the membrane exterior. |
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Explain hydrophobic tails. |
Made of hydrocarbon fatty acids insoluble in water (45%), protein bilayer (50%) and sugar + cholestrol (5%). Negatively charged, directed to membrane interior. |
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What are the types of transport membrane mechanisms and what are their differences? |
Passive - does not require energy. Active - energy from ATP is required. |
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Explain simple diffusion. |
Transports H2O, solutes &gases. Goes from high concentration to low, total volume does not change. Diffusion rate is established using Fick's law. Works like tea-making. |
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What is the difference between linear and nonlinear diffusion? |
Linear depends on concentration gradient, matter solubility and temperature of surroundings. Nonlinear depends on size of particles. |
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What are the types of diffusion? |
Simple, facilitated and through protein channels. |
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Explain facilitated diffusion. |
Passive transport of bigger molecules, works like scissors, uses protein carrier that undergoes confirmation.
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Explain diffusion through ion channels. |
Passive transport of Na+, K+, Ca+, Cl- or low molecular soluble substances. Channels are voltage/ligand gated. |
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Explain the difference between voltage and ligand gated ion channels. |
Voltage gated open and close due to membrane electricity. Ligand gated open when e.g. a hormone binds to the channel. |
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Explain the process of filtration. |
Passive transport of water and small molecules. From high hydrostatic pressure to low. Driven by pressure gradient of hydrostatic pressure. |
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Explain osmosis. |
Passive transportation of water through a semipermeable membrane, from low concentration to high. Total volume of solution in both compartments changes. |
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What is osmolarity? |
Concentration of a solution, total number of solute particles per litre. Normally 300mOsm/l. |
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What are isotonic, hypertonic and hypotonic solutions? |
Isotonic solution - normal osmolarity (0.9%NaCl). Hypotonic solution - osmolarity is lower than 0.9%. Hypertonic solution - osmolarity is higher than 0.9% |
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What is active transport? |
Molecules are transported against concentration. Energy from ATP is crucial. |
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What is the difference between primary and secondary active transport? |
Primary - through ion selective channels (pumps). secondary - substance binds on ion and is transported. |
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What is the Na+K+ pump (ATP-ase)? |
It is an enzyme within cell membrane. Carries 3Na+ outside and 2K+ inside. Max 200Na+/133K+ per second. Requires energy. Important for elecric charges renewal. |
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What is exo-cytosis? |
"cell vomiting". Release of larger molecules by protrusion of cell membrane. Requires Ca+ ions and energy. |
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What is endo-cytosis? |
"cell eating". Uptake of molecules by cell membrane. Requires energy. |
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What is phagocytosis? |
Endo-cytosis when leukocytes ingest bacteria. |
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Explain resting membrane potential. |
Electric potential difference resulting of membrane semipermeability. Measured between +charged cell exterior and -charged cell interior. Has negative value. Equals to a sum of equilibrium potentials of all 3 ions. |
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What is the value of resting membrane potential in cells? |
In nerve cells -70mV. Skeletal muscle cells -90mV. Heart muscle cells 80mV and smooth muscle cells -50mV (non stable). |
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What is the sum of equilibrium potential of the 3 main ions at rest? |
K+:Na+:Cl- = 1:0.04:0.45 in % = 100:4:45 |
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What is equilibrium potential? |
Value of electiral voltage that stops passive diffusion of ions & their concentration gradients. Established with Nernst formula. (mV) |
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How is a cell charged and why? |
Cell is positively charged outside and negatively inside. Because of proteins outside and Na+ inside. |
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What is the size of a cell and how thick is it? |
2-120 µm and thickness is 7 nm. |
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What happens with surface tension in lungs? |
Surfactant reduces surface tension. |
