Question

Part B The graph shows three reaction pathways for the same biological reaction One reaction pathway shows an uncatalyzed reaction, while two reaction pathways show catalyzed reactions: one catalyzed by enzyme X and one catalyzed by Y. For this particular biological reaction, enzyme X is a better catalyst than enzyme Y. Which statements apply to each reaction? Products Reaction pathway

Answer 1

Catalyst is a substance which increases rate of reaction without taking part into chemical reaction.

It provides a different path for a given chemical reaction having low activation energy.

activation energy is the minium amount of energy required to initiate a reaction.

Consider a energy profile diagram as shown below.

• Reaction pathway

From given energy profile diagram it is clear that , Reaction A is uncatalayzed reaction.

Reaction A has highest activation energy and therefore it is slower reaction.

Reaction B and Reaction C are catalyzed reactions by enzymes.

There are two enzymes 1) enzyme X and 2) enzyme Y

Enzyme X is better catalyst than enzyme Y. Hence, reaction C which has lowst activation energy is catalyzed by enzyme X . Reaction C will be fastest reacction as it requires less activation energy.

Reaction B is catalyzed by enzyme Y.

ANSWER

Reaction A	Reaction B	Reaction C
Slowest reaction uncatalyzed reaction Highest activation energy	Catalyzed by enzyme Y	Fastest reaction Catalyzed by enzyme X Lowest acivation energy