in temperature will damage the permeability of the plasma membrane. Also‚ the heat will break away the permeability. If the pH solution is 7 or greater there will be no change but the lower the pH the more proteins in the membrane deteriorate. This was believed because its very common that with heat applied to something‚ the ’object’ expands‚ this is seen with metals. Due to this‚ we assumed that the same would happen to animal and plant cells and the cell membrane. It’s also believed that the low
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EXCRETION Excretion is the removal of unwanted substances such as toxic materials and wastes products of metabolism from organisms. These unwanted substances can be :- 1. Waste products from body metabolism (chemical reactions in the body). 2. Excess water and salts taken in with the diet. 3. Spent hormones. 4. Drugs and other foreign substances. Excretion occurs in specialized organs of the body called the excretory organs. There are two excretory organs in human body :- a) Lungs b)
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down to the axon terminal of the presynaptic neuron. Each axon terminal becomes swollen forming a presynaptic knob. There is a depolarisation of the presynaptic membrane resulting from the action potential. This depolarisation causes an increase in the permeability to sodium and calcium ions. The presynaptic knob is then filled with membrane-bound vesicles; each filled with a neurotransmitter. Calcium ions then flood into the presynaptic knob by diffusion. The influx of calcium ions triggers the exocytosis
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partially permeable membrane allows water into the pill and dissolve the drug. Hence‚ the dissolved drug will diffuse out of the pill. 1‚3 2‚ 4‚ 5 Bile emulsifies fats. It causes fats droplets to breakdown into fat molecules‚ increasing the surface area to volume ratio‚ hence increasing the speed of digestion of fats. Amylase digested the starch in the visking tubing to form maltose. Since maltose is a small molecule‚ it was able to diffuse out of the visking tubing‚ down a concentration
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1. a. The action potential changes the membrane potential from -70 mV (resting) to +30 mV and back again to the resting membrane potential. b. This results from a change in membrane permeability first to Na then to K due to the opening of what type of ion channels? Voltage gated channels 2. a. Where is the density of voltage-gated Na+ channels the greatest? Axon hillock b. What areas of the neuron generate signals that open these voltage-gated channels? Dendrites and the cell body c. Opening
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|A protein found in muscle cells. It is the main component of the thin filaments. | |Action potential |A brief reversal of the resting potential across the cell surface membrane of a neurone. All action | |
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Bag 3 had a rate of osmosis equal to 0.0471 grams per minute. Bag 4 had a rate of osmosis equal to 0.0886 grams per minute. Bag 5 had a rate of osmosis equal to -0.0914 grams per minute (Figure A). Figure A: Shifting of mass in grams for each dialysis bag was measured every 5 minutes for 30 minutes. Bag 1 contained DI H2O and was submerged in DI H2O. Bags 2‚ 3‚ and 4 were submerged in DI H2O and contained 20%‚ 40%‚ 60% sucrose‚ respectively. Bag 5 was submerged in 60% sucrose and contained DI
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region of high concentration to a region of low concentration across a partially permeable membrane. Osmosis is complete when all of the water molecules have been evenly spread out and can take place either in plant cells or animal cells‚ so long as a partially permeable membrane is present. Osmosis can also be conducted in the visking tubing experiment‚ where the visking tubing is an artificial permeable membrane. So how does Osmosis take place? When you put an animal or plant cell into liquid containing
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fluid-mosaic model of a plasma membrane. Discuss the role of the membrane in the movement of materials through each of the following processes: a.) Active Transport b.) Passive Transport All living cells contain a plasma membrane‚ which acts a boundary for the cell. The plasma membrane regulates the cell’s chemical composition because it uses selective permeability to allow certain substances to enter or exit the cell more easily than others. The formation of this membrane is believed to be one of
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The Nervous System: Membrane Potential 1. Record the intracellular and extracellular concentrations of the following ions (mM/L): | Intracellular | Extracellular | Sodium (Na+) | 15 | 150 | Potassium (K+) | 150 | 5 | Chloride (Cl–) | 10 | 125 | 2. Excitable cells‚ like neurons‚ are more permeable to K+ than to Na+. 3. How would the following alterations affect the membrane permeability to K+? Use arrows to indicate the change in permeability. a. An increase in the number of passive
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