Urgent! Can someone please answer these questions? Thank you for your time!

Question

1. Changing environmental conditions, such as temperature or pH, can affect enzyme shape. How would this alter the enzyme's function?
2. Food contains large, complex molecules that cannot be easily absorbed into the body and used by cells. Bread, for example, contains starch, which is a polysaccharide. Digestive enzymes break down these complex molecules into smaller molecules the body can use. What would happen if digestive enzymes were not present?

Thank you!!!

Answer 1

Hi Juliana!

1) Every enzyme has a pH optimum, where all of its amino acids are protonated and de-protonated in the spot that will maximize their intramolecular interactions and their intermolecular interactions with the substrate it acts as a catalyst on. Enzymes in the stomach such as pepsin will function optimally at a low pH because of the stomach's acidic environment. Additionally, certain species may have the same enzyme, but each has a different melting temperature (Tm) in which it degrades and is no longer functional based on the environment it has evolved in. Thermus thermophilus for instance, which live in extreme temperatures lie hot springs, will be able to withstand temperatures of up to 90 degrees Celsius until their enzymes are no longer functional. Changing environmental conditions like pH and temperature may result in protein unfolding or simply not allow the enzyme to function at it's optimum due to one amino acid being de-protonated, eliminating the interacting force between it and its substrate (like a key that cannot fit a lock).

2) In the absence of digestive enzymes, large polymers such as protein and starch would be unable to be absorbed by the cells of the small intestine. We require these enzymes to break these large molecules down into their monomeric units (i.e. amino acids and glucose) in order to bypass the intestinal barrier and be utilized by the body. Large, undigestible polymers such as fiber provide nutrients to the bacteria living in our gut, and while their smaller byproducts (butyrate) may be absorbed by the body, leftovers are simply defecated and never enter the body.