The active site has a specific shape which is exactly the right shape for the substrates. It has an indentation on the surface called the active site. In an enzyme the reactants (things on the left of the equation) are called substrates. A catalyst is not changed by the reaction РІР‚вЂњ therefore it can be used over and over again. A catalyst speeds up a chemical reaction. digestive enzymes) work outside the cell. Most of them work inside the cell, but some (e.g. Each type of enzyme acts on a specific type of food.Р”В®nzymes are proteins. They do not actually take part in the reaction or change it in any way except to make it happen faster. Enzyme Action РІР‚вЂњ enzymes are chemicals which speed up (catalyse) other reactions.The muscles also move the food along the gut from one area of chemical digestion to another. It also helps the chemical breakdown of the food, mixing it with various digestive juices, which break down its molecules. It helps to break up the food into very small pieces with a large surface area for enzyme action to take place. Muscular Action РІР‚вЂњ The gut is a muscular tube and its squeezing action is very important.The working of the digestive system is based on two things: Only the terms in italics are needed by most GCSE boards. The appendix is a small cul-de-sac at the base of the caecum. It is useful to know that the small intestine consists of the duodenum, jejunum and ileum and the large intestine consists of the caecum, colon and rectum in that order.

Finally the waste products leave the body in the form of faeces through the anus. When all the useful products have diffused into the blood, the remaining waste reaches the large intestine where the majority of the remaining water is absorbed into the blood stream. There is a rich blood supply to maintain a steep concentration gradient for diffusion. It is long and folded with villi to increase surface area. The small intestine walls are very thin so that there is a short diffusion pathway. Food molecules diffuse in the small intestine, which is ideal for this purpose. The enzymes are used to fully digest the food molecules, so that they are small enough to diffuse into the bloodstream. The pancreas, a pistol shaped organ, produces the enzymes amylase, lipase and protease and releases them into the small intestine when needed. The small intestine produces amylase, lipase and protease. The gall bladder stores the bile made by the liver until it is needed. Bile also neutralizes the acid produced by the stomach to provide ideal alkaline conditions for enzymes in the small intestine. This will increase the rate at which the fat is digested by lipase. breaks them down into small droplets for a larger surface area. The liver produces bile which emulsifies fats i.e. produces hydrochloric acid which kills bacteria and gives the ideal pH for protease to work.produces protease enzymes to digest protein.The stomach does a number of things, including: The gullet then carries food from the mouth to the stomach by its muscular squeezing action called peristalsis. Also inside the mouth, amylase (for digesting starch) can be found, produced by the salivary glands. more info.Digestion begins inside the mouth, where chewing does 2 things - makes the food easier to swallow and increases the surface area (this helps to speed up digestion). To support the redundant system, it provides dedicated parameter settings. GX Developer is a comprehensive programming tool that improves work efficiency in development, debugging, and.

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