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22 Cards in this Set
- Front
- Back
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Roles of membranes |
Site of chemical reactions Site of cell communication Partially permeable barriers |
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What is the role of cholesterol in a plasma membrane |
Mechanical stability and flexibility |
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Name the 3 proteins in a plasma membrane |
Peripheral, carrier, channel |
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What is the bilayer made out of |
Phospholipids |
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What is a glycoprotein |
A carbohydrate chain attached to a protein receptor site, on the outside of the membrane |
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What is a glycolipid |
A carbohydate chain attached to a lipid on the outside of the membrane |
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What is the role of the carbohydrate molecules in glycolipids and glycoproteins |
Since they are hydrophilic, the molecules attract water with dissolved solutes, helping the cell interact with its watery enviroment and obtain dissolved substances |
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What effect does a decrease in temperature have on the membrane structure and permeability regarding phospholipids |
Membrane becomes less fluid and less permeable (opposite effects when temperature increases) |
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What effect does an increase in temp have on the proteins in a membrane |
Proteins became denatured due to the H and ionic bonds breaking, causing their tertiary structure to change |
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What experiment would you do to see the effect of temperature and solvents on cell membranes |
Beetroot experiment |
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What is the difference between diffusion and facilitated diffusion? |
Facilitated diffusion is always across a partially permeable membrane via protein channels or carriers |
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What are the 5 factors that affect the rate of simple diffusion |
Temperature, diffusion distance, surface area, size of diffusing molecule, concentration gradient |
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How is the concentration gradient maintained |
The molecules entering the cell then pass into organelles and are used for metabolic reactions |
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What is cytolysis |
When a cell swells up and bursts due to a lot of water molecules entering, occurs in animal cells |
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What does crenated mean |
When an animal cell shrivels due to water molecules leaving |
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What does plasmolysed mean |
When the cytoplasm of a plant cell shrinks and the membrane pulls away from the cellulose cell wall |
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What is endocytosis |
When the plasma membrane surrounds the particle and encloses it in a vesicle, which is now in the cell |
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Exocytosis |
Where a vesicle in the cell moves towards and fuses with the plasma membrane. The particle can now leave the cell |
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What do active transport, endocytosis and exocytosis all have in common |
They all require ATP |
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How do you investigate the factors that affect the rate of diffusion |
Add universal indicator solution to a model cell |
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What is water potential and what is the water potential of pure water |
Measure of the tendency of water molecules to diffuse from one region to another
0 kPa |
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How does cholesterol reduce the effects of changing temperature on the cell membranes stability |
It either prevents the phospholipids from packing too closely when the temperature drops or... Reduces the increase in membrane fluidity when the temperature increases |
