Problem 114 - Objective Biology for NEET

Question

Select the correct statement: (a) Increase in substrate concentration, increases the velocity of enzymatic reaction at first then it reaches maximum and further increment does not occur. (b) In competitive inhibition, the inhibitor closely resembles the substrate in its molecular structure. (c) Competitive inhibition are often used in the control of bacterial pathogens. (d) All of these

Step-by-Step Solution

Answer

Therefore, the statement (d) 'All of these' is the correct answer as all the statements (a), (b), and (c) are accurate.

Step 1: Analyze statement (a)

Statement (a) is true. The rate of enzymatic reactions does increase with an increase in substrate concentration up to a certain point. After that point, (the maximum reaction velocity or Vmax), further increments in substrate concentration do not increase the rate of reaction because the enzymes are working at their maximum capacity and cannot process any more substrates.

Step 2: Analyze statement (b)

Statement (b) is also true. In competitive inhibition, the inhibitor molecule closely resembles the substrate in its molecular structure and competes with the substrate for the active site on the enzyme. The inhibitor can bind to the active site, preventing the substrate from binding and slowing down the reaction.

Step 3: Analyze statement (c)

Statement (c) is true as well. Competitive inhibitors are frequently used in the control of bacterial pathogens. Many drugs work by being competitive inhibitors and prevent the bacteria from carrying out necessary metabolic reactions.

Key Concepts

Substrate Concentration

Enzymatic reactions are often influenced by the concentration of substrate, which is the substance an enzyme acts upon. At the beginning, increasing the substrate concentration usually speeds up the rate of the reaction. This is because more substrate molecules are available for the enzymes to act on. However, this increase in reaction speed does not continue indefinitely.

• The reaction rate will increase until it reaches a point known as the maximum reaction velocity, or Vmax.
• At Vmax, all the active sites of the enzyme molecules are occupied by substrate.
• When this saturation point is reached, adding more substrate will not increase the reaction rate.

This is because the enzymes are already operating at full capacity. Understanding how substrate concentration affects enzyme activity is crucial for appreciating how biochemical reactions are regulated in different environments.

Competitive Inhibition

In the process of competitive inhibition, a molecule that resembles the enzyme's normal substrate binds to the enzyme's active site. This is the same location where the substrate binds during a standard enzymatic reaction.

• The inhibitor molecule competes with the substrate for the active site.
• This is only possible because the inhibitor strongly resembles the substrate in structure.
• When the inhibitor binds to the active site, it prevents the substrate from binding and slows down the reaction.

The key to competitive inhibition is that it can be overcome by increasing the concentration of the substrate. At higher levels of substrate, the likelihood of the substrate binding to the enzyme rather than the inhibitor increases. This concept is important for understanding how to regulate enzymatic activity in a variety of settings, from biological processes to drug design.

Bacterial Pathogens Control

Controlling bacterial pathogens often involves inhibiting the metabolic pathways essential for their survival. Competitive inhibition is a common strategy used for this purpose.

• Several drugs designed to control bacterial infections work by acting as competitive inhibitors.
• These drugs target specific bacterial enzymes and prevent them from binding to their natural substrates.
• This inhibition stops vital processes within the bacteria, ultimately saving the host from infection.

This approach is advantageous because it allows for specificity; the drug targets only bacterial enzymes, leaving human enzymes unaffected. Understanding competitive inhibition in this context helps in pharmaceutical development and the creation of antibiotics capable of combating resistant bacterial strains.