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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. Enzyme: is defined as a globular protein molecule that accelerates a specific chemical reaction. It is biological catalyst which speeds up a reaction without changing it in any other way. Active site: a region of an enzyme's surface binds the substrate (reacting substance) during the reaction cayalysed by the enzymes.

(2) Without enzymes, why would so many reactions be so slow? Enzymes make it easier for a reaction to take place. The substrate will bind to active site. As all catalysts, enzymes do not alter the position of the chemical equilibrium of the reaction. Usually, in the presence of an enzyme, the reaction runs in the same direction as it would without the enzyme, just more quickly. However, in the absence of the enzyme, other possible uncatalyzed, "spontaneous" reactions might lead to different products, because in those conditions this different product is formed faster

(3) Draw the lock & key model of enzyme activity. Write a few sentences to explain this. (4) Write 4-5 really good sentences to describe this process. The two substances needing to combine, meet up at the active site in the enzyme. The enzymes catalyses the specific reaction and the two substances become one. Or, when a big molecule needs breaking down, they go to the active site in the enzyme. The enzymes break the molecules apart and the big molecule is now broken down into two or more products.

(5) What is the connection between enzymes & activation energy? Enzymes are catalysts, mostly in the form of proteins. This means, that enzymes temporarily bind to one or more of the reactants of the reaction they catalyze (the picture below shows this). Because of this, less activation energy is needed (graph of number 9). (6) What are some of the differences between the enzyme pepsin & the enzymes on the membrane of mitochondria? Enzymes pepsins are used in the human stomach, while the enzymes on the membrane of mitochondria function on the inside of the cell. On top of that enzyme pepsins are activated through the acid in the human stomach. Enzymes on the membrane of mitochondria are active, but do not function in acid liquids.

(7) Why are enzymes so specific? <span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">Enzymes are specific beause many reactions cannot occur without the right enzyme. Its shape must match the shape of the substrate like a key fitting into a lock. Enzymes, therefore, must be specific since they'll only function correctly if the shape of the substrate matches the active site. <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) The induced fit model of enzyme activity is when the substrate fits together with the enzyme, the enzyme will change itself to either join two substrates together of break it down. The lock & key model, however, is where the substrate has to be able to fit into the enzyme; the enzyme's shape will not alter according to the structure of the 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.

**__The graph of activation energy and the effect of the enzymes__**
====Enzymes are biological catalysts. A catalyst speeds up a reaction without changing it 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 helps to reach this equilibrium faster. With the help of enzyme, the activation energy can happen in the lower temperature. Without enzyme, the cell cannot live and continue the living activities because all reactions happen slowly.====

<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. <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;">Denaturation is the change in the structure of some substrates which leads to the change of the original factors  Proteins have 3 kinds of structure. When the proteins change their structure because of the effect of the temperature, pH, ..., the factors are changed. This reation is called Denaturation.

Denaturation of proteins involves the disruption and possible destruction of both the secondary and tertiary structures. Since denaturation reactions are not strong enough to break the peptide bonds, the primary structure (sequence of amino acids) remains the same after a denaturation process. Denaturation disrupts the normal alpha-helix and beta sheets in a protein and uncoils it into a random shape. Denaturation occurs because the bonding interactions responsible for the secondary structure (hydrogen bonds to amides) and tertiary structure are disrupted. In tertiary structure there are four types of bonding interactions between "side chains" including: hydrogen bonding, salt bridges, disulfide bonds, and non-polar hydrophobic interactions. which may be disrupted. Therefore, a variety of reagents and conditions can cause denaturation. The most common observation in the denaturation process is the precipitation or coagulation of the protein.