Internal Assessment on Enzymes

Of the many functions of proteins, catalysis is by far the most vital. When catalysis is not present, most reactions in the biological systems take place very slowly to produce at an adequate pace for metabolising organism. The catalysts that take this role are called enzymes. Enzymes are the most efficient catalysts; they can enhance rate of reaction by up to 1020 over uncatalysed reactions. (Campbell et al, 2012).

Enzymes are biological catalysts that speed up chemical reactions, without being used up or changed. Catalase is a globular protein molecule that is found in all living cells. A globular protein is a protein with its molecules curled up into a 'ball' shape. All enzymes have an active site. This is where another molecule(s) can bind with the enzyme. This molecule is known as the substrate. When the substrate binds with the enzyme, a product is produced. Enzymes are specific to their substrate, because the shape of their active site will only fit the shape of their substrate. It is said that the substrate is complimentary to their substrate.

Enzymes are types of proteins that work as a substance to help speed up a chemical reaction (Madar & Windelspecht, 104). There are three factors that help enzyme activity increase in speed. The three factors that speed up the activity of enzymes are concentration, an increase in temperature, and a preferred pH environment. Whether or not the reaction continues to move forward is not up to the enzyme, instead the reaction is dependent on a reaction’s free energy. These enzymatic reactions have reactants referred to as substrates. Enzymes do much more than create substrates; enzymes actually work with the substrate in a reaction (Madar &Windelspecht, 106). For reactions in a cell it is

Enzymes are biological catalysts, which speed up the rate of reaction without being used up during the reaction, which take place in living organisms. They do this by lowering the activation energy. The activation energy is the energy needed to start the reaction.

Enzymes are catalysts that function to speed up reactions; for example, the enzyme sucrose speeds up the hydrolysis of sucrose, which breaks down into glucose and fructose. They speed up reactions but are not consumed by the reaction that is taking place. The most important of the enzyme is the shape as it determines which type of reaction the enzyme speeds up. Enzymes work by passing/lowering and energy barrier and in doing so; they need to bind to substrates via the active. Once they do, the reaction speeds up so much more quickly than it would without the enzyme. Coenzymes and cofactors aid the enzyme when it comes to binding with the substrate. They change the shape of the active site so the substrate can bind properly and perform its function.

Hold the IKI spray bottle 25 - 30 cm away from the paper towel, and mist with the IKI solution.

Enzymes are defined as catalysts that speed up chemical reactions but remain the same themselves. The shape of an enzyme enables it to receive one type of molecule and that specific molecule will fit into the enzyme’s shape. Where a substance fits into an enzyme is called the active site and the substance that fits into the active site is called a substrate. Several factors affect enzymes and the rate of their reactions. Temperature, pH, enzyme concentration, substrate concentration, and the presence of any inhibitors or activators can all affect enzymes. Temperature can affect enzymes because if the temperature gets too high, it can cause the enzyme to denature. pH can affect an enzyme by changing the shape of the enzyme or the charge properties of the substrate so that either the substrate cannot bind to the active site or it cannot undergo catalysis. Every enzyme has an ideal pH that it will strive in. Increasing substrate concentration increases the rate of reaction because more substrate molecules will be interacting and colliding with enzyme molecules, so more product will be formed. Inhibitors can affect enzymes and the rate of their reactions by either slowing down or stopping catalysis. The three types of inhibitors include competitive, non-competitive, and substrate inhibition.

Enzymes are a key aspect in our everyday life and are a key to sustaining life. They are biological catalysts that help speed up the rate of reactions. They do this by lowering the activation energy of chemical reactions (Biology Department, 2011).

“Enzymes are proteins that have catalytic functions” [1], “that speed up or slow down reactions”[2], “indispensable to maintenance and activity of life”[1]. They are each very specific, and will only work when a particular substrate fits in their active site. An active site is “a region on the surface of an enzyme where the substrate binds, and where the reaction occurs”[2].

Organisms cannot depend solely on spontaneous reactions for the production of materials because they occur slowly and are not responsive to the organism's needs (Martineau, Dean, et al, Laboratory Manual, 43). In order to speed up the reaction process, cells use enzymes as biological catalysts. Enzymes are able to speed up the reaction through lowering activation energy. Additionally, enzymes facilitate reactions without being consumed (manual,43). Each enzyme acts on a specific molecule or set of molecules referred to as the enzyme's substrate and the results of this reaction are called products (manual 43). As a result, enzymes promote a reaction so that substrates are converted into products on a faster pace (manual 43). Most enzymes are proteins whose structure is determined by its sequence of its amino acids. Enzymes are designed to function the best under physiological conditions of PH and temperature. Any change of these variables that change the conformation of the enzyme will destroy or enhance enzyme activity(manual, 43).

There are thousands of chemical reactions that occur in an organism that make life possible. Most of these chemical reactions occur too slowly on their own. Enzymes are protein catalysts that speed up chemical reactions in a cell. Catalysts are not changed by the reactions they control, and are not used up during the reaction. Enzymes therefore, can be used over and over again. Enzymes are large complex proteins made by the cell and allow chemical reactions to take place at the temperature of the cell. These catalysts are needed in only very small amounts because a single enzyme molecule can complete the same reaction thousands of times in one minute.

Enzymes are very efficient catalysts for biochemical reactions. They speed up reactions by providing an alternative reaction pathway of lower activation energy. Like all catalysts, enzymes take part in the reaction - that is how they provide an alternative reaction pathway. But they do not undergo permanent changes and so remain unchanged at the end of the reaction. They can only alter the rate of reaction, not the position of the equilibrium. Enzymes are usually highly selective, catalyzing specific reactions only. This specificity is due to the shapes of the enzyme molecules.

An enzyme is a catalyst. Catalysts are known for speeding up the rate of reactions by lowering the activation energy of the biochemical reaction. (Reece et al., 2011)

Since enzymes are biochemical catalysts, made up at least partially of protein, they are sensitive in varying degrees to heat. Raising temperatures of the environment generally multiplies the degree of activity by the enzyme. Once an optimum temperature has been reached, however, temperatures that are too high will denature the enzyme it will loose its ability to function. Cofactors are agents that are necessary for an enzyme to carry out a transformation. An apoenzyme is the enzyme without the cofactor and the holoenzyme is the active species made by combining the cofactor with the apoenzyme. The coenzymes are small organic molecules that are non-peptide in nature and are sometimes also known as a prosthetic group. Vitamins are small organic molecules that act as coenzymes although not all coenzymes are vitamins. A vitamin is a molecule that cannot be produced within the body and must be introduced i.e. through diet. Another example of enzyme regulation is that of competitive inhibitors. If a reversible inhibitor can bind to the enzyme active site in place of the substrate, it is described as a "competitive inhibitor." In pure competitive inhibition, the inhibitor is assumed to bind to the free enzyme but not to the enzyme-substrate complex. When a non-competitive inhibitor binds to the enzyme at the regulatory site, the shape of the active site changes so that it can no longer bind its substrate or catalyze the production of

Enzymes are proteins that act as catalysts and help reactions take place. In short, enzymes reduce the energy needed for a reaction to take place, permitting a reaction to take place more easily. Some enzymes are shape specific and reduce the energy for certain reactions. Enzymes have unique folds of the amino acid chain which result in specifically shaped active sites (Frankova Fry 2013). When substrates fit in the active site of an enzyme, then it is able to catalyze the reaction. Enzyme activity is affected by the concentrations of the enzymes and substrate present (Worthington 2010). As the incidence of enzyme increases, the rate of reaction increases. Additionally, as the incidence of substrate increases so does the rate of reaction.