Aim: What is an Enzyme and how does it speed up a chemical reaction? Do Now: In your own words, describe what happens to meat when you cook it. (what it looks like, feels like, ect) Day 9 Aim: What is an Enzyme and how does it speed up a chemical reaction?

What is an enzyme? An enzyme is a special protein. Because enzymes are proteins, they are 3 dimensional molecules. There shape is important for the job they do. Enzymes speed up chemical reactions in the body. The name of an enzyme always end with “ase” – example lactase which works on lactose.

Why do enzymes need to have a specific shape? Enzymes fit onto other molecules called substrate. Substrates are any molecule that an enzymes fits onto and does something to it. Once attached, the enzyme will either take that molecule apart or put it together with another molecule. (Combining 2 molecules) H2O2 H2O + O2 Hydrogen peroxide water oxygen gas catalase substrate

Types of Biological Reactions that Enzymes do Digestion (Breakdown)- one molecule is broken down into two or more smaller molecules Synthesis- two or more smaller molecules react to form a larger molecule Poof Poof

What is the Lock and Key Model? The lock-and-key model explains why enzymes increase the rate of chemical reactions. When an enzyme is near a substrate, it holds the substrate in place allowing the reaction to occur. Since each enzyme has a specific shape, only those substrates with the correct shape will be worked on.

The Lock-and-Key Model

The Lock-and-Key Model Enzyme

Why do enzymes speed up chemical reactions? Without an enzyme, the substrates cannot hit each other at the correct angle, so the reaction is slow. Reactions occur by chance. With an enzyme, the substrates fit into the enzyme’s active site at just the right angle, so the reaction is fast.

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What you need to know about the Parts of an Enzyme’s Reaction 1) Enzymes contain specific areas where the substrate can bond to them. Active sites These areas are called active sites.

2) When the substrates become attached to the enzyme, the whole thing is called the enzyme-substrate complex.

What can affect enzymes? Under normal reactions, enzymes are not destroyed. They can be reused over and over again. Although enzymes have specific shapes, these shapes can change if the environmental conditions surrounding the enzyme changes. If the enzymes shape changes, then the enzyme cannot do its job. An enzyme’s shape is affected by temperature and pH changes. Each type of enzyme has its own temperature and pH that it works it best. This best temperature and pH is known as its optimum.