Get an answer in 5 minutes
We'll notify as soon as your question has been answered.
Hi Zahid, Enzymes at GCSE level are really simple once you wrap your head around them. Enzymes are biological catalysts. This means they speed up chemical reactions within your cells to keep you alive! Enzymes work by fitting their specific substrate(s) (sort of like reactants) into their active site. What this means is that the enzyme/substrate system works like a lock and key, where the enzyme is the lock, the substrate is the key. The enzyme is shaped in such a way that there is a section of it that is the exact shape of its substrate. The enzyme is specific to its own substrate. The substrate binds with the enzyme at this specifically shaped spot (the active site) and the substrate is released, after being broken down into two smaller products (degradation) or two smaller substrates are combined into one larger product (synthesis). The shape of the enzyme does not change as a result of this, so it can be reused for another substrate. Enzymes work best at certain temperatures and pH levels. For human enzymes, the temperature is around 37°C (which is why your body is at this temperature). The pH varies, however, for example this is why your stomach contains acid - to accommodate for the enzymes in your stomach. However, when the conditions an enzyme is in exceed tolerable limits of temperature and pH, they become denatured. This means that the shape of their active site has changed, so they cannot bind with their specific substrate any longer. This means the reaction happens much slower, and eventually kills the organism. This is why body temperature is so important! Human enzymes tend to denature at around 60°C. And since the optimum pH changes, the tolerable limits for each enzyme change too. Denaturing is irreversible. When an enzyme gets too cold, it does not denature, but the enzyme activity slows down and eventually stops. When the organism is heated again however, the enzyme activity eventually returns to normal. I hope this helped in some way! If you have any more questions, feel free to ask me and I’ll do my very best to answer them. Thanks, Graeme