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Complete the following question to create your own notes. Good full answers please as you need to understand your notes in a year’s time!

**(1) Define enzyme & active site. ** An enzyme is a protein molecule that acts as a biological catalyst. This means that it accelerates the speed of a reaction without changing it in any other way. This is shown in the diagram below: The active site is the area of the surface of an enzyme where it binds the substrate (reacting substance) during the reaction catalyzed by the enzyme.

**(2) Without enzymes, why would so many reactions be so slow? **

Enzymes are catalysts, and the role of a catalyst is to speed up biological reactions without changing in any other way. Adding an enzyme to a reaction does not create different products and does not alter the reaction’s equilibrium. It only helpsto reach this equilibrium faster. Enzymes are not usedup in the reactions they catalyse.

In the absence of these enzymatic catalysis most biochemical reactions are too slow that they would not occur under mild conditions such as temperature and pressure to be capable of life.

Enzymes accelerate the rates of such reactions so much, so reactions that would years in the absence of catalysis can occur in fractions of seconds catalysed by the appropriate enzyme.

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**(3) Draw the lock & key model of enzyme activity. Write a few sentences to explain this. ** The lock is the enzyme wherethe key is the substrate. Only the correctly sized key (substrate) will fit inside the key hole (active site) of the lock (Enzyme)

**(4) Write 4-5 really good sentences to describe this process. **

**(5) What is the connection between enzymes & activation energy? **

Activation energy is the substantial amount of energy that is often required for a chemical reaction to take place, due to the strength of the bonds that need to be broken. The energy is rarely provided by the molecules colliding, so other factors are necessary to help the molecules clear the energy barrier (the amount of activation energy to start a reaction), and cause the chemical reaction. One of these factors includes to add the appropriate enzymes to the reaction, as enzymes are catalysts and speed up reactions without being affected themselves.

So the connection between enzymes and activation energy, is that enzymes help molecules produce the substantial amount of energy for the reaction to take place. <span style="display: block; margin: 0in 0in 0pt 0.5in; mso-list: l0 level1 lfo1; tab-stops: list .5in; text-indent: -0.5in;">**<span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">(6) What are some of the differences between the enzyme pepsin & the enzymes on the membrane of mitochondria? **

<span style="display: block; margin: 0in 0in 0pt 0.5in; mso-list: l0 level1 lfo1; tab-stops: list .5in; text-indent: -0.5in;">**<span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">(7) Why are enzymes so specific? ** The structure of the protein determines the shape of the active site. The substrate then fits into the active site and the reaction occurs. Another molecule of a different shape will not fit into the same active sites, so it cannot react with the same enzyme. Therefore, an enzyme only works with a specific substrate and catalyzes a specific reaction.

<span style="display: block; margin: 0in 0in 0pt 0.5in; mso-list: l0 level1 lfo1; tab-stops: list .5in; text-indent: -0.5in;">**<span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">(8) How does the induced fit model of enzyme activity differ from the lock & key model? (You need to think for yourselves for this one) ** []

Lock and Key <span style="color: #595959; display: block; font-family: Calibri; font-size: 9pt; margin: 0in 0in 0in 0.375in;">Pasted from <[]> Induced Fit <span style="color: #595959; display: block; font-family: Calibri; font-size: 9pt; margin: 0in 0in 0in 0.375in;">Pasted from <[]>
 * <span style="direction: ltr; display: block; margin-bottom: 0px; margin-top: 0in; unicode-bidi: embed; vertical-align: middle;"> A model for enzyme-substrate [|interaction] suggesting that the [|enzyme] and the [|substrate] possess specific [|complementary] geometric shapes that fit exactly into one another. Like a key into a lock, only the correct size and shape of the [|substrate] ( the key ) would fit into the [|active site] ( the key hole ) of the [|enzyme] ( the lock ).
 * <span style="color: black; direction: ltr; display: block; margin-bottom: 0px; margin-top: 0in; unicode-bidi: embed; vertical-align: middle;"> The change in shape of the active site of an enzyme so that it binds more snugly to the substrate, induced by entry of the substrate.

For the lock and key model, the substrate and the active site has to match perfectly to react, but not for the induced fit model, since the active site changes its shape to bind with substrate.

<span style="display: block; margin: 0in 0in 0pt 0.5in; mso-list: l0 level1 lfo1; tab-stops: list .5in; text-indent: -0.5in;">**<span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">(9) Draw a graph to show the activation energy and how enzymes affect this. Describe how catalysts make this reaction go faster. ** <span style="display: block; font-family: Arial,Helvetica,sans-serif; font-size: 120%;">As seen in the graph, the Activation energy with enzymes caused the reaction to progress faster, which shows that enzymes, being catalysts speed up reactions without being effected.

<span style="display: block; margin: 0in 0in 0pt 0.5in; mso-list: l0 level1 lfo1; tab-stops: list .5in; text-indent: -0.5in;">**<span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">(10) Define denaturation & explain its effect on proteins (including enzymes, which are proteins). **

Denaturation is when the structure of a protein is disrupted. Denaturation does not destroy peptide bonds, so the protein is not completely destroyed, but it disrupts the alpha-helix of the protein and uncoils it into a random shape. Denaturation can happen when the protein is exposed to acids and bases, heavy metals , heat , or alcohol.