All of the following are categories of lymphocytes except:
A. B cells
B. Q cells
C. T cells
D. NK cells
The correct answer and explanation is :
The correct answer is B. Q cells.
Explanation:
Lymphocytes are a type of white blood cell that plays a crucial role in the immune system. There are several categories of lymphocytes, but Q cells do not exist in the scientific understanding of immune system cells. Let’s break down the correct lymphocyte categories and explain why Q cells is the incorrect choice:
- B Cells:
B cells, or B lymphocytes, are responsible for humoral immunity. They mature in the bone marrow and play a crucial role in the production of antibodies. When exposed to an antigen (a foreign substance), B cells differentiate into plasma cells that secrete antibodies. These antibodies bind to the antigen, marking it for destruction or neutralization by other immune cells. Some B cells become memory cells, which can quickly respond to future infections by the same pathogen. - T Cells:
T cells, or T lymphocytes, are responsible for cell-mediated immunity. They mature in the thymus and are essential in identifying and destroying infected cells, cancer cells, and foreign cells. There are several types of T cells, including Helper T cells (which aid other immune cells in their function) and Cytotoxic T cells (which kill infected or cancerous cells). T cells are essential in controlling the immune response and maintaining the balance of the immune system. - NK Cells:
NK cells, or Natural Killer cells, are a part of the innate immune system. They are specialized in identifying and destroying virus-infected cells and tumor cells. Unlike B and T cells, NK cells do not require prior exposure to a pathogen to be activated. They recognize stressed or abnormal cells and induce apoptosis (programmed cell death) to prevent the spread of infections or cancer. - Q Cells:
The term Q cells does not correspond to any known category of lymphocytes. There is no established immunological category or function for “Q cells” in the scientific literature, making this option incorrect.
In summary, B, T, and NK cells are well-defined categories of lymphocytes, each playing a distinct and critical role in the immune response. Q cells, on the other hand, is a non-existent term in this context, making B the correct answer.