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Biology {Movement in and out of Cells, Enzymes Summer} :sunglasses: -…
Biology {Movement in and out of Cells, Enzymes Summer} :sunglasses:
Enzymes
Effect of Temperature: increase in temperature, increase kinetic energy, increases number of collisions between enzyme active site and substrate, increases enzyme activity, so there will be more enzyme-substrate complexes produced. It is best at optimum temperature. Past optimum temperature enzymes begin to denature (structure breaks and active site loses its shape)
Effect of pH: Either side of the optimum pH affects the structure of the active site and causes it to denature. This means that they cannot make the enzyme-substrate complexes.
Investigate Effect of Temperature & pH Method:
1) Label each well with a time and add a drop of iodine.
2) Prepare a range of temperatures of water baths.
2) Add 2cm^2 of buffer solution of different range of pH.
3) Transfer 3cm^2 of amylase to tube in water bath, do the same with starch suspension.
4) Allow solutions to equilibrate and stir them.
5) Put a drop into the first well (0)
6) Repeat step 5 every minute, rinsing glass rod between each until the iodine does not turn blue-black.
7) Record results in a table.
8) Calculate the rate of enzyme reaction using 1/time taken for iodine solution to remain brown
9) Repeat with other temperature water baths.
9) Repeat with other buffer solutions and pHs.
10) Plot a graph with rate of enzyme reaction against temperature
Equipment spotting tile, pipette, amylase, iodine and starch solution, stop watch, glass rod
Sources of Error: The intervals between testing samples may be too long to accurately measure the time taken for
the starch to be completely broken down
Safety Measures tie hair back, safety glasses, hot water,
bunsen burners
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Properties of Enzymes
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not used up in chemical reactions (denaturation- irreversible, enzymes can no longer work as the active site loses the complementary shape)
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lock and key hypothesis-active site of enzyme with complementary shape to substrate attaches to create an enzyme-substrate complex kick-starting the chemical reaction
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Plant Cells
Distilled Water - water moves into cells, down a concentration gradient, there is a higher water potential outside the cell, this pushes the cell membrane against the cell wall, the plant cell becomes turgid
Saturated Water- water leaves the cells, down a concentration gradient, higher water potential inside the cells, this causes cell membrane to shrink away from the cell wall, the plant cell becomes plasmolyzed/flaccid.
Red Blood Cells
Distilled Water- water moves into the cell, down a concentration gradient, there is a higher water potential outside the cell, this causes the cell to swell and burst because animal cells don't have cell walls
Saturated Water- water leaves the cell, down a concentration gradient, higher water potential inside the cells, this causes the cell to shrink