Study "enzymes", a flashcard deck on FORKSAI.
Define the term metabolism.
Metabolism is the sum of all chemical reactions that take place within an organism. It encompasses both anabolic reactions (building up) and catabolic reactions (breaking down) that control the chemical and energy requirements of a cell.
What is an enzyme?
An enzyme is a protein catalyst found in living organisms that speeds up chemical reactions without being used up in the reaction. Enzymes are crucial for controlling cell metabolism.
Describe the protein nature and folded structure of enzymes.
Enzymes are proteins composed of long chains of amino acids that fold into a very specific three-dimensional globular shape. This precise shape, particularly the active site, is essential for the enzyme to function and attach to its specific substrate.
Explain the role of enzymes in metabolism in plants and animals.
Enzymes play a critical role in metabolism by controlling all chemical reactions within an organism. In both plants and animals, they facilitate reactions that obtain and utilize energy, such as breaking down food (catabolic) or building complex molecules (anabolic).
How does an enzyme function according to the active site theory (Lock and Key model)?
According to the lock and key model, an enzyme functions because its active site has a complementary shape to its specific substrate. The substrate binds to the active site, forming an enzyme-substrate complex, where the reaction occurs, either breaking bonds or encouraging new ones.
Explain what is meant by the specificity of an enzyme.
Enzyme specificity refers to an enzyme's ability to react with only one particular substrate or a very limited range of substrates. This is due to the unique three-dimensional shape of its active site, which only allows molecules with a complementary shape to bind and react.
What is the effect of pH on enzyme action?
pH affects enzyme action by influencing the hydrogen bonds that maintain the enzyme's specific shape. Deviations from the optimum pH can alter the active site's shape, reducing the enzyme's efficiency, and extreme pH changes can cause denaturation, permanently losing its function.
What is meant by the 'optimum' pH of an enzyme?
The optimum pH of an enzyme is the specific pH value at which the enzyme exhibits its maximum activity and efficiency. At this pH, the enzyme's active site has the best fit for its substrate, allowing for the fastest reaction rate.
Explain how high temperatures denature enzymes.
High temperatures cause the molecules to vibrate more vigorously, breaking the hydrogen bonds that maintain the enzyme's specific three-dimensional shape, particularly the active site. This permanent change in shape, known as denaturation, renders the enzyme unable to bind to its substrate and thus unable to function.
Describe the process of immobilising enzymes.
Immobilising enzymes involves attaching biological catalysts to an inert material, either chemically or physically. This process prevents the enzymes from being freely dissolved in the reaction mixture, allowing for their reuse and easier separation from products.