Enzymes Flashcards iGCSE Biology

[q] What are Enzymes?

[a]Proteins that function as biological catalysts are called Enzymes.

• Biological / made by cells;
  
• Catalyst / speeds up the rate of a reaction;
  
• Made of protein;

[q] Explain how digestive enzymes function?

[a]

• Enzymes are protein;
• Enzymes can be reused / are unchanged in the reaction;
• Enzymes are specific;
• Enzymes are catalysts / speeds up reaction;
• Lowers the energy needed for the reaction;
• Successful collisions / enzyme-substrate complex /esc;
• Active site;
• Enzyme and substrate fit together;
• Complementary shape;
• Digestive enzymes perform chemical digestion / hydrolysis / catabolic reactions;
• Break down, large / insoluble, molecules into, small / soluble, molecules; 

[q] Temperature and Enzymes

[a] As the temperature increases up to the enzyme’s optimum, the rate of reaction increases. This is because the molecules have more kinetic energy, thus move faster. Consequently, more successful collisions occur, and more enzyme-substrate complexes can form. At very high temperatures above the optimum, the enzymes become denatured and the active site changes shape. Substrate cannot fit into denatured enzymes as the shape of their active site has been lost. This decreases the rate of reaction as enzyme-substrate complexes cannot form.