Question

station 26 - enzyme - substrate complex
describe the enzyme - substrate complex:
bonds w/ the enzyme + fits into enzyme
substrate
what is formed from the enzyme - substrate complex?
products + move on to the substrate
using amylase and starch as an example, what are the products formed from the enzyme - substrate complex?
once amylase has broken down starch, can it break down another starch molecule?
enzymes can also join

molecules together,
resulting in

station 27 - enzymes in action
describe the saltine piece in the cup after one minute (including how much had it changed?)
describe the saltine piece in your mouth after one minute (including how much had it changed)?
why was the saltine in your mouth different than the saltine in the cup with water?

Explanation:

• Enzyme - substrate complex: It is formed when the substrate binds to the active site of the enzyme. The enzyme may change its shape slightly (induced - fit model) to accommodate the substrate.
• Products formed from the enzyme - substrate complex: The enzyme - substrate complex is converted into enzyme - product complex, and then the products are released. The enzyme remains unchanged (in most cases) and can bind to another substrate molecule.
• Amylase and starch example: Amylase acts on starch (a polysaccharide). The products formed are maltose (a disaccharide). The reaction is \( \text{Starch} + n\space\text{H}_2\text{O}\xrightarrow{\text{Amylase}}n\space\text{Maltose} \)
• Reusability of amylase: Yes, once amylase has broken down starch, it can break down another starch molecule. Enzymes are not consumed in the chemical reactions they catalyze.
• Enzymes joining molecules: Enzymes can also join smaller molecules together, resulting in larger molecules. For example, DNA ligase joins DNA fragments (smaller molecules) to form a longer DNA strand (a larger molecule)

• Saltine in cup (water): After one minute, the saltine in the cup with water may have started to dissolve slightly. The change is mainly due to physical dissolution (osmosis and simple diffusion of water into the saltine, and some of the soluble components of the saltine dissolving in water). The change is relatively slow as it is a physical process.
• Saltine in mouth: In the mouth, the saltine will change more significantly. Saliva contains amylase. The amylase in saliva starts to break down the starch in the saltine (a chemical change). The saltine will become softer and may start to lose its shape more rapidly compared to the one in water.
• Difference between saltine in mouth and in cup: The saltine in the mouth is different because of the presence of enzymes (like amylase) in saliva. These enzymes catalyze the breakdown of starch (a chemical reaction), while in the cup with water, only physical dissolution (a physical process) occurs

Answer:

• Enzyme - substrate complex: Substrate binds to enzyme's active site (may involve shape change).
• Products: Enzyme - product complex → products + unchanged enzyme.
• Amylase - starch products: Maltose.
• Amylase reusability: Yes.
• Enzymes joining molecules: Smaller; larger molecules.
• Saltine in cup: Slight dissolution (physical change).
• Saltine in mouth: More breakdown (chemical change due to amylase).
• Difference: Mouth has enzymes (catalyze starch breakdown), cup has only physical dissolution.