Answer Happy

How is toxicity quantified? One way to express the relative toxicity of a compound is to determine an LD50 (lethal dose 50%) value. The LD50 is the concentration of a substance that is expected to kill 50% of the sample population. For example, just 60 mL of methanol would likely kill 50% of average Americans who weigh 175 lbs, whereas it would take 1.5 L of propylene glycol to have the same effect. What distinguishes the toxicity of different alcohols? The answer has less to do with the alcohol itself and more with how the human body metabolizes the alcohol. The five alcohols initially presented are similarly toxic on their own, but some are quickly converted to less toxic compounds, whereas others are converted to more toxic compounds. It is important to understand how the human liver detoxifies potentially dangerous molecules that are ingested. The digestive tract is a hollow passageway that passes through the human body. However, the interior of the tract of the esophagus, stomach, and intestines is considered to be outside the body. When a person ingests something, molecules are absorbed into the body through the various parts of the digestive tract, particularly through the small intestine. These absorbed molecules then enter the bloodstream. Where does this blood go first? The venous blood from the intestinal tract flows directly into the liver, allowing the liver to serve as a first-pass filter, protecting the rest of the body from the impact of potentially dangerous substances. Thus, the liver has an active role in detoxifying many compounds that human beings commonly ingest. These detoxification reactions are all catalyzed by various enzymes made in the liver.
Which statement correctly describes proteins and enzymes? Most enzymes are proteins. All proteins are enzymes. No enzymes are proteins.
Which statement most correctly describes of the role of enzymes in catalysis? Enzymes make reactions possible by changing the ground state of the reaction. Enzymes make reactions thermodynamically favorable. Enzymes react with substrates to form products that contain the enzyme. Enzymes speed up chemical reactions in one direction. Enzymes lower the activation energy of a reaction.
The shape of an enzyme's active site is most complementary to which structure? the substrate the transition state the ground state the product molecule