Question

1. which of the following best explains why enzymes are necessary for many cellular reactions? a. enzymes supply the oxygen necessary for reactions. b. enzymes change reactants from solid to liquid during reactions. c. the reactions take up too much space in the cell if enzymes are missing. d. the reactions are too slow to meet the needs of the cell if enzymes are missing. for numbers 16 - 17, please use the graph below. 16. at which ph value does pepsin function best? a. 4.0 b. 3.5 c. 3.0 d. 4.5 17. based on the graph, if the enzyme trypsin was placed into an environment that had a ph of 4, the trypsin would function how? a. best b. worst c. it would not function at all d. none of the above 18. lactose is a disaccharide found in milk. when lactose is digested by the human body, each lactose molecule is broken down into smaller molecules. what are these smaller molecules called? a. polymers b. monomers c. amino acids d. dna 19. in the human body, fibrinogen is necessary for sealing cuts and stopping the loss of blood. since fibrinogen is made of chains of amino acids, it is an example of which type of organic molecule? a. carbohydrates b. protein c. fatty acids d. nucleic acids

Explanation:

1. Enzymes are biological catalysts that speed up chemical reactions in cells. Without them, reactions would be too slow to support cellular functions. Option A is incorrect as enzymes don't supply oxygen. Option B is wrong since they don't change reactants' states like that. Option C is not the main reason.
2. By observing the graph for pepsin, the peak of its activity occurs around pH 3.0, indicating it functions best at this pH.
3. Looking at the trypsin graph, its optimal pH range is around 8 - 10. At pH 4, which is far from its optimal range, it would function worst.
4. Disaccharides like lactose break down into monosaccharides during digestion. Polymers are large - molecule structures made of monomers. Amino acids are building blocks of proteins and DNA is a genetic material.
5. Proteins are made up of chains of amino acids. Fibrinogen, being made of amino - acid chains and having a biological function related to blood - clotting, is a protein. Carbohydrates are made of sugar units, fatty acids are part of lipids, and nucleic acids are DNA and RNA.

Answer:

1. D. The reactions are too slow to meet the needs of the cell if enzymes are missing.
2. c. 3.0
3. b. worst
4. b. Monomers
5. b. protein