Enzymes’ key points are taken from past papers of entry tests. Important points and numerical values MDCAT Biology chapter-wise notes with definitions. Enzymes are biological catalysts, which means that they speed up a chemical reaction without being used up.
In this article, we’ll talk about some of the most important things from FSC Biology chapter 3 about enzymes, so you’ll know what to expect next semester in class and on your exams. Read on to find out what’s coming if you want to get ahead before it all starts up again.
The Definition of an Enzyme:
An enzyme is a catalyst, which means it speeds up a chemical reaction without being used up itself. The ability of an enzyme to speed up a reaction depends on its three-dimensional shape, which lets it fit into and change a given substrate. In other words, enzymes speed up reactions by giving substrates specific places to recognize them.
The substrate binds to these recognition sites (enzymes usually have more than one) and changes shape slightly, making it easier for it to react with other molecules. The way your body burns food is an example of how an enzyme speeds up a reaction. Digestion starts in your mouth, where enzymes like salivary amylase break down complex carbs into simple sugars that can be absorbed by your gut lining.
Substrates of an Enzyme:
To fit into an enzyme’s binding site, the substrate must be of a certain size and shape. The enzyme is also picky about what kinds of bonds are in its substrate, which helps it decide if it will make its product. If these things don’t come together, it can’t speed up the reaction.
This is what scientists call the “specificity” of an enzyme. The real place: Once a certain type of molecule binds to the active site, or binding site, of an enzyme, they interact in a series of ways that change a small part of the molecule into another small part called a product. Catalysis is the name for this process (or catalytic conversion). A catalyst is something that speeds up a chemical reaction or helps it along but doesn’t get used up in the process.
Enzymes Key Points Chapter 3
Here is a list of enzyme key points from MDCAT Biology for entry test preparation.
- The enzyme is a Greek word: en- inside, Zyme – yeast
- As it is Best discovered in yeast that’s why its name is an enzyme.
- the First enzyme was discovered by Anselme Payen in 1833, and the enzyme was the carbohydrate digesting enzyme; diastase.
- The word enzyme was first coined by Wilhelm Kuhne in 1877.
- The first enzyme was purified by Sumner in 1926.
- Enzymes are globular proteins.
- All enzymes are proteins except ribozyme which is chemically RNA but performs the activity of the enzyme.
- rRNA found in the large subunit of the ribosome is ribozyme and is also called peptidyl transferase which has a role in the formation of the peptide bond. ,
- Enzymes are named by adding ‘use’ to the name of substrate they act, ‘ e.g. proteases, lipases, etc.
FSC Biology Unit 3 Enzyme Important Points:
- Enzymes are named by taking into consideration both the substrate acted upon and the type of reaction catalyzed, e.g. DNA-polymerase.
Some enzymes are named as per the substance synthesized e.g. rhodonite catalyzes the synthesis of rhodonite from hydrochloric acid and sodium thiosulphate.
The substrate is a substance on which an enzyme acts.
- The region of the enzyme where the substrate attaches is called the active site.
The most active site is composed of 3 – 12 amino acids. These amino acids have a specific alkyl group that has a role in catalyzing the reaction.
- The region of the enzyme other than the active site is called an allosteric site.
Some enzymes do not work until a non-proteinous part is attached, this non-proteinous part is called a cofactor. ,
- If the cofactor is organic then it is called co-enzyme. For example NADP,
FAD etc. = contains vit.
- Co-enzyme are mostly composed of part of vitamin B. e.g.
B3 (also called niacin or nicotinic acid or nicotinamide), FAD contains vIt 82 (ribof7avin) co-enzyme A contains Vit B5 pantothenic acid)
- If the cofactor is inorganic then it is called a prosthetic group
- Some enzyme required metallic ions for their best activity e.g hexokinase is the first enzyme used in glycolysis that requires Mg+” ion, carbonic anhydrase require Zn++ ion, and enterokinase requires Ca++.