Systemschapter). These enzymes would not work optimally at other pHs. Trypsin is
another enzyme in the digestive system which break protein chains in the food into
smaller parts. Trypsin works in the small intestine, which is not an acidic environment.
Trypsin’s optimum pH is about 8.- Biochemical reactions are optimal at physiological temperatures. For example, most
biochemical reactions work best at the normal body temperature of 98.6 ̊F. Many
enzymes lose function at lower and higher temperatures. At higher temperatures, an
enzyme’s shape deteriorates and only when the temperature comes back to normal
does the enzyme regain its shape and normal activity.
Lesson Summary
- Elements are substances that cannot be broken down into simpler substances with
different properties. - Elements have been organized by their properties to form the periodic table.
- Two or more atoms can combine to form a molecule.
- Molecules consisting of more than one element are called compounds.
- Reactants can combine through chemical reactions to form products.
- Enzymes can speed up a chemical reaction.
- Living things are made of just four classes of macromolecules: proteins, carbohydrates,
lipids, and nucleic acids.
Review Questions
- What is density?
- What are the 4 main classes of organic compounds?
- Would water, with the symbol H 2 O, be considered an element or a compound?
- How many types of atoms make up gold?
- Why do you need fats in your diet?
- Sugar is what kind of organic compound?
- What is an atom?
- What monomers make up proteins?
- Name a few examples of proteins.
- Name a few examples of lipids in organisms.
- What are two nucleic acids?
Further Reading / Supplemental Links