Investigating the Effects On the Rate of an Enzyme Controlled Reaction (Amylase and Starch)

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Biology Coursework: Investigating the Effects on the Rate of an Enzyme Controlled Reaction

Aim:

The aim of our investigation is to see the effect temperature has on the rate of en enzyme controlled reaction. The enzyme and the substrate we are using are Amylase and Starch. Amylase being the enzyme and starch being the substrate. The concentrations we are sing are (0.1mol of Amylase and 1mol of starch).

Introduction:

Enzymes are substances in plants and animals that speed biochemical reactions. Enzymes can build up or break down other molecules. The molecules they act on are called substrates. Enzymes are catalysts--chemicals that hasten a chemical reaction without undergoing any change themselves.

Most enzymes are huge protein molecule. Highly specific, each usually catalyzes only one type of chemical reaction. Some enzymes consist of a protein and a helpful nonprotein component called a prosthetic group. When the prosthetic group is loosely linked to the protein, it is called a coenzyme. Vitamins are important parts of these coenzymes. Since enzyme molecules are far larger than those of their substrates, their catalytic action occurs only at a small active site on the enzyme. The substrate and the enzyme fit together at the active site like a

Lock and a key. This accounts for an enzyme's specificity for a particular substrate. Then the chemical bond holding the substrate together is weakened in the enzyme-substrate activated complex, and the substrate molecule is broken down into smaller products. After disengagement, the enzyme is free to perform its catalytic action again. If a coenzyme is needed to reduce a substrate it floats to the basic enzyme molecule when a reaction is about to take place, links with the enzyme and substrate, and then disengages itself from the enzyme when the biochemical task is finished.

Many enzymes are catalysts in reactions that build molecules. In a similar lock-and-key fashion,

Diagram Of Lock and Key Method

they fasten smaller molecules together.

Enzymes are formed at cell sites called ribosomes. Amino acids, the building blocks of proteins, are brought to the ribosomes and strung together in a precise manner to form the enzymes. These then float free within the cell or into nearby body areas where they are needed. The genetic code that determines protein structure also directs the amino-acid sequence of enzymes. The genes of a species control the kinds of enzymes its members make.

Enzymes that exist in nature are usually named for their substrates, with the suffix -ase added on. The enzyme lipase, for example, acts on fatty lipids. However, some of the first enzymes discovered were not named in this way. Among them was the enzyme pepsin, which breaks down proteins.

Enzymes are divided into six categories based on their function. The hydrolases usually split their substrates with the aid of water. The lyases split their substrates without aid. The transferases transfer chemical groups between different molecules. The isomerases rearrange the molecules of their substrates. The oxidoreductases transfer hydrogen ions. The ligases, or synthetases, help release energy.

Enzymes are unchanged by the reaction they catalyse. Therefore a small amount of enzyme can catalyse the conversion of a lot of substrate into a lot of product.

Enzymes are made inactive at high temperatures and become ...