Enzymes

• Why do organisms need enzymes?

  As most chemical reactions are naturally very slow.
• Why don't we increase the temperature of our cells to increase the rate of chemical reactions?

  Heating our cells would require a lot of energy, higher temperatures could damage our cells, higher temperatures would also speed up non-useful reactions.
• What is a catalyst?

  A catalyst is a substance that increases the rate of a chemical reaction without being consumed in the process.
• What is an enzyme?

  An enzyme is a protein that acts as a catalyst in biological reactions, speeding up the rate of the reaction without being consumed in the process.
• What is the name of the special region of an enzyme that binds to the substrate?

  Active site.
• What do we call the complex that is formed when an enzyme binds to a substrate?

  Enzyme-substrate complex.
• When discussing enzymes, what does 'complementary' mean?

  A substrate must be complementary to the active site of the enzyme. This means that it is the right match, or 'fits' the active site.
• What is the lock and key model of enzyme action?

  The lock and key model of enzyme action describes how enzymes (the lock) specifically fit with substrates (the key) to catalyze reactions.
• What is the induced fit model of enzyme action?

  The induced fit model of enzyme action suggests that the enzyme changes shape to fit the substrate upon binding, enhancing catalysis.