Bio Case Study

Part I 1) 2)

Part II 1) 2)

3)

The products of oxidation for methanol are formic acid, lactic acid and formaldehyde (methanal). The products oxidation for ethanol are acetaldehyde (ethanal) and ethanoic acid. Ethanol is a competitive inhibitor and it prevents the conversion of methanol into its toxic products by competing for active sites of the enzyme, alcohol dehydrogenase. The ethanol from the mixture decreases the amount of toxin produced, hence the children were not as severely poisoned.

The presence of ethanol will decrease the rate of reaction of methanol to its products. Controlled variable: Concentration of enzymes and methanol Dependent variable: Rate if reaction Independent variable: Concentration of methanol, presence of ethanol Similarities and differences between competitive and non-competitive inhibition Competitive inhibition

Non-competitive inhibition

Inhibitor binds to active site

Inhibitor binds to site other than active site

Inhibitor resembles substrate in terms of structure

Inhibitor does not structurally resemble substrate

Competes with substrate for active site

Changes conformation of enzyme

Usually reversible if there is enough substrate to displace the inhibitor

Usually reversible

Amount of enzyme inhibition depends upon inhibitor concentration, substrate concentration and relative affinities of inhibitor and substrate for active site

Not affected by substrate concentration

4) 5) The presence of ethanol decreases the rate of reaction of methanol. As the concentration of methanol increases, the rate of reaction increases at a decreasing rate with and without ethanol. The graph where ethanol is present approaches the graph where ethanol is absent, hence it can be inferred that an increase in solute concentration (methanol) is able to displace the inhibitor (ethanol). Therefore, competitive inhibition is evident. 6) As ethanol has a similar structure as methanol, it acts as a competitive inhibitor and prevents the conversion of methanol into its toxic products by competing for and binding onto active sites of the enzyme, alcohol dehydrogenase. As less methanol can be converted, the amount of toxin produced decreases, hence the children were not as severely poisoned.