All statements given are correct, except :

Question

Accepted Answer

The correct option is 3:
This option states that "Morphine and Cellulose are alkaloids," which is the *incorrect* biological statement among the choices, and therefore the correct answer to the question. To understand why, we must analyze the chemical classification of each substance. **Morphine** is unequivocally an **alkaloid**, a class of naturally occurring organic compounds that predominantly contain basic nitrogen atoms, and it is derived from the opium poppy. However, **Cellulose** is fundamentally and chemically different. Cellulose is a complex **carbohydrate**, specifically a **polysaccharide**. It is a polymer made up of thousands of glucose units linked together in long chains and forms the main structural component of plant cell walls. Since one member of the pair (Cellulose) is a carbohydrate and not an alkaloid, the entire combined statement is factually inaccurate.

The incorrect option is 1:
This statement, "Insulin and Trypsin both are proteins," is factually correct. **Insulin** is a small protein, classified as a peptide hormone, which is composed of two polypeptide chains (A and B) linked by disulfide bonds. It is secreted by the pancreas and its primary biological role is to regulate blood glucose levels. **Trypsin**, on the other hand, is a proteolytic enzyme, a type of digestive enzyme produced in the pancreas. Since enzymes are biological catalysts, and nearly all biological enzymes, including Trypsin, are macromolecules made up of chains of amino acids, they are classified as proteins. Therefore, both Insulin and Trypsin are correctly categorized as proteins, despite having different functions—hormone signaling versus enzymatic catalysis.

The incorrect option is 2:
The statement "Abrin and Ricin are toxins" is factually correct. Both **Abrin** and **Ricin** are notorious, highly potent plant toxins. Ricin is a protein isolated from the seeds of the castor oil plant (*Ricinus communis*), and Abrin is a similar protein found in the seeds of the jequirity pea (*Abrus precatorius*). These substances function as Ribosome-Inactivating Proteins (RIPs). This mechanism means they are capable of entering a cell and permanently modifying the cell’s ribosomal RNA, thereby halting all protein synthesis. Due to this extremely disruptive cellular process, even minute quantities of these molecules are lethal to humans and animals, confirming their classification as biological toxins.

The incorrect option is 4:
The statement "Vincristin and Vinblastine are drugs" is correct. They are well-known compounds that are, more specifically, vital **chemotherapeutic drugs** used in cancer treatment. Both **Vincristine** and **Vinblastine** are naturally occurring plant alkaloids derived from the Madagascar periwinkle (*Catharanthus roseus*). Their therapeutic value stems from their function as anti-mitotic agents. They work by binding to tubulin proteins and preventing them from polymerizing into microtubules, which are essential for forming the mitotic spindle. By disrupting the mitotic spindle, they effectively arrest cell division, which is critical for preventing the proliferation of rapidly dividing cancer cells in the body.