#### • Class 11 Physics Demo

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#### • enzyme experiment temperature

Question:Enzymes function most efficiently at the temperature of a typical cell, which is 37 degrees Celsius. Increases or decreases in temperature can significantly lower the reaction rate. What does this suggest about the importance of temperature-regulating mechanisms in organisms?

Answers:It's all about homeostasis. Most endothermic species have enzymes which have an optimum temperature at 37 degrees c. Ectothermics species (reptiles etc) may have enzymes which have lower optimum rates. For humans, internal functions will operate efficiently provided that temperature regulation occurs. If temperatures fluctuate too much i.e. Go to 45 degrees c, only only would you be dead, but sugar levels, and waste product levels would build up internally causing organ failure. Ultimately it's vital for temperature relating mechanisms to sustain homeostasis.

Question:is this a correct Expt to show affect of temperature on enzymes: --- - Take a spotting tile with 20 spots, each spot containing some iodine solution (same amount) - Add 1cm3 of a 1% amylase solution to 5cm3 of a 1% starch solution in a test tube -Keep temperature constant (start at 20o) - Every 30 seconds (from 0 seconds) add some of the amylase-starch solution to the iodine in one of the spots. - The longer it takes before the iodine stays orange, the slower the action of the enzyme -Make sure that the volume of solution added to each spot, is the same throughout expt - Repeat the experiment, raising the temperature by about 5o each time (the smaller the range the greater the accuracy of the expt) - Notice the closer the temperature gets to 37 the faster the reaction - At about 40 / 45 the starch will keep turning the iodine black enzyme is denatured (amylase no longer breaks down the starch)

Answers:Sounds good but have some additional control tubes - 1.Amylase and water (no starch). 2.Water and starch (no amylase) 3.Boiled amylase and starch. Make sure all tubes are same volume and test them as you test the experimental tube.

Question:I did a lab on potato enzymes and i was wondering what is supposed to happen when the temperature of the enzyme reaction is changed? (0, 21, 37, 100 C) I know 100 C the enzymes stop function but is it most affective at 37 degrees? Potato enzyme + hydrogen peroxide --> H2O+O2

Answers:I did a lab similar to yours in Bio like last week! Each enzyme has their own optimum temperature because we have different body parts which have different temperatures. I don't know about potato enzymes but probably they work at a colder temperature because they grow underground.

Question:The effects of pH and temperature were studied for an enzyme-catalyzed reaction. These result were obtained: Enzyme activity for temperature are high, while enzyme activity for pH are low. How do (1) temperature and (2) pH affect the activity of this enzyme? What is the relationship between the structure and the function of this enzyme? How are structure and function of enzymes affected by temperature and pH? How can a controlled experiment produce either temperature or pH? What hypothesis was tested?

Answers:I JUST ANSWERED WHAT IS SIMILAR TO THAT QUESTION YESTERDAY...SO THAT WAS THE ANSWER Gonna talkin generally and u focus on what u want There are several factors that affect the rate of reaction: 1) Concentration: Reaction rate increases with concentration, as described by the rate law and explained by collision theory. As reactant concentration increases, the frequency of collision increases. 2) The nature of the reaction: Some reactions are naturally faster than others. The number of reacting species, their physical state (the particles that form solids move much more slowly than those of gases or those in solution), the complexity of the reaction and other factors can influence greatly the rate of a reaction. 3) Temperature: Usually conducting a reaction at a higher temperature delivers more energy into the system and increases the reaction rate by causing more collisions between particles, as explained by collision theory. However, the main reason why it increases the rate of reaction is that more of the colliding particles will have the necessary activation energy resulting in more successful collisions (when bonds are formed between reactants). The influence of temperature is described by the Arrhenius equation. As a rule of thumb, reaction rates for many reactions double or triple for every 10 degrees Celsius increase in temperature, though the effect of temperature may be very much larger or smaller than this (to the extent that reaction rates can be independent of temperature or decrease with increasing temperature!) For example, coal burns in a fireplace in the presence of oxygen but it doesn't when it is stored at room temperature. The reaction is spontaneous at low and high temperatures but at room temperature its rate is so slow that it is negligible. The increase in temperature, as created by a match, allows the reaction to start and then it heats itself, because it is exothermic. That is valid for many other fuels, such as methane, butane, hydrogen... 4) Solvent: Many reactions take place in solution and the properties of the solvent affect the reaction rate. The ionic strength as well has an effect on reaction rate. 5) Pressure: The rate of gaseous reactions increases with pressure, which is, in fact, equivalent to an increase in concentration of the gas. 6) Electromagnetic Radiation: Electromagnetic radiation is a form of energy so it may speed up the rate or even make a reaction spontaneous, as it provides the particles of the reactants with more energy. This energy is in one way or another stored in the reacting particles (it may break bonds, promote molecules to electronically or vibrationally excited states...) creating intermediate species that react easily. For example when methane reacts with chlorine in the dark, the reaction rate is very slow. It can be sped up when the mixture is put under diffused light. In bright sunlight, the reaction is explosive. 7) A catalyst: The presence of a catalyst increases the reaction rate (in both the forward and reverse reactions) by providing an alternative pathway with a lower activation energy. For example, platinum catalyzes the combustion of hydrogen with oxygen at room temperature. 8) Isotopes: The kinetic isotope effect consists in a different reaction rate for the same molecule if it has different isotopes, usually hydrogen isotopes, because of the mass difference between hydrogen and deuterium. 9) Surface Area: In reactions on surfaces, which take place for example during heterogeneous catalysis, the rate of reaction increases as the surface area does. That is due to the fact that more particles of the solid are exposed and can be hit by reactant molecules. 10) Order: The order of the reaction controls how the reactant concentration affects reaction rate. All the factors that affect a reaction rate are taken into account in the rate equation of the reaction. --------------------------------------... ANSWERS If u needed a recorded lecture for that lecture ..i have it..just all upon u..I have no problems in sending it to you..CHEERS --------------------------------------------------------------------------- ANSWERS also if u need KInetics Quizes ...just tell me..I need them Rather wasting ur time..U must solve quizes as a sort of focusing and testing your degree in understanding Kinetics -----------------------------------------------------------------------------