Which of the following statement is incorrect?

The RNA can be removed by treatment with protease whereas proteins can be removed by treatment with ribonuclease.

The correct answer is Option (3)- The RNA can be removed by treatment with protease, whereas proteins can be removed by treatment with ribonuclease. 

The RNA can be removed by treatment with protease, whereas proteins can be removed by treatment with ribonuclease. This statement is incorrect.  Protease enzymes are used to break down proteins, not RNA. Ribonuclease enzymes, on the other hand, are used to degrade RNA molecules.

(1) In a method known as micro-injection, recombinant DNA is directly injected into the nucleus of an animal cell .This is correct . In the micro-injection method, recombinant DNA is indeed directly injected into the nucleus of an animal cell. This technique is commonly used in genetic engineering to introduce foreign DNA into specific cells for various purposes, such as gene editing, gene expression studies, or producing transgenic organisms.

(2) A stirred-tank reactor is usually cylindrical or with a curved base to facilitate the mixing of the reactor contents. - This statement is correct. A stirred-tank reactor is usually cylindrical or with a curved base to

facilitate the mixing of the reactor contents. The stirrer facilitates even mixing and oxygen availability throughout the bioreactor. Alternatively, air can be bubbled through the reactor. The bioreactor has an agitator system, an oxygen delivery system and a foam control system, a temperature control system, pH control system and sampling ports so that small volumes of the culture can be withdrawn periodically.

(4) In genetic engineering, DNA from different sources is cut with the same restriction enzymes so that both DNA fragments have the same kind of sticky ends. - This statement is correct. Restriction enzymes are used to cut DNA at specific recognition sites, resulting in DNA fragments with sticky ends that can easily be ligated or joined together with other DNA fragments. Using the same restriction enzyme ensures that the DNA fragments have compatible sticky ends for successful ligation during gene cloning and recombinant DNA technology.