whats an enzyme?

Question

mrs p begging for answers for 12 year old sons homework before my brain explodes!!!!!!!!!!!!!!

Answer 1

Enzymes are proteins that accelerate, or catalyze, chemical reactions. In these reactions, the molecules at the beginning of the process are called substrates and the enzyme converts these into different molecules: the products. Almost all processes in the cell need enzymes in order to occur at significant rates. Consequently, since enzymes are extremely selective for their substrates and speed up only a few reactions from among many possibilities, the set of enzymes made in a cell determines which metabolic pathways occur in that cell.

Enzymes are known to catalyze about 4,000 reactions. However, not all biological catalysts are proteins, since some RNA molecules called ribozymes can also catalyze reactions. Enzymes are usually named according to the reaction they catalyze. Typically the suffix -ase is added to the name of the substrate (e.g., lactase is the enzyme that cleaves lactose) or the type of reaction (e.g., DNA polymerase forms DNA polymers).

Like all catalysts, enzymes work by providing an alternative path of lower activation energy for a reaction and dramatically accelerating its rate. Some enzymes can make their conversion of substrate to product occur many millions of times faster. For example, the reaction catalysed by orotidine 5'-phosphate decarboxylase will consume half of its substrate in 78 million years if no enzyme is present. However, when the decarboxylase is added, the same process takes just 25 milliseconds. Chemically, enzymes are like any catalyst and are not consumed in chemical reactions, nor do they alter the equilibrium of a reaction. However, enzymes do differ from most other catalysts by being much more specific.

Enzyme activity can be affected by other molecules. Inhibitors are molecules that decrease enzyme activity, and activators are molecules that increase activity. Drugs and poisons are often enzyme inhibitors.

Some enzymes are used commercially, for example, in the synthesis of antibiotics. In addition, some household cleaning products use enzymes to speed up chemical reactions (e.g., enzymes in biological washing powders break down protein or fat stains on clothes).

Answer 2

Basically the last person was right, it is a protein that speeds up a reaction. (Not a cell as someone else wrote). Enzymes are biological catalysts (he may have come across that word in chemistry). Enzymes are also the active part of Biological washing powder.

There are lots of enzymes in every cell in your body and they allow all the different chemical reactions we need to live to happen. They make them happen quickly enough and at low enough temperatures that we can use them in our body.

Some important points about enzymes that may be useful:
They are very specific (they only work on the exact molecule you want them too)
They work at your body temperature.
Some of them have evolved so that their activity can be changed according to the presence or absence of different signals.

Answer 3

An enzyme is a biological catalyst (It helps reactions along in living things) Enzymes are proteins. They are very specific - only facilitating one reaction. For example amylase (in the saliva) breaks down starch into sugars.

Answer 4

An enzyme is a protein.

Answer 5

Its somthing to do with science i learnt about it last year i think its found in an animal or plant-hope you get a good awnser though good luck x

Answer 6

http://en.wikipedia.org/wiki/Enzyme

Good Luck

Answer 7

an enzyme is a small cell in the intestine that barkes down startch molycules etc

Answer 8

it's a protein tha speeds up reactions

Answer 9

simply its a biological catalyst and is a globular protein

Answer 10

sorry no idea but surley there is some thing on the web that will help you