AP BIOLOGY

Detailed explanation-1: -Some types of white blood cells, called phagocytes (FAH-guh-sytes), chew up invading organisms. Others, called lymphocytes (LIM-fuh-sytes), help the body remember the invaders and destroy them. One type of phagocyte is the neutrophil (NOO-truh-fil), which fights bacteria.

Detailed explanation-2: -Lymphocytes help your body’s immune system fight cancer and foreign viruses and bacteria (antigens). Lymphocytes help your immune system remember every antigen it comes in contact with. After an encounter, some lymphocytes turn into memory cells.

Detailed explanation-3: -Memory lymphocytes can recognize an antigen introduced into the body during a prior infection or vaccination. Memory lymphocytes mount a rapid and strong immune response when exposed to an antigen for a second time. Both T lymphocytes (T cells) and B lymphocytes (B cells) can become memory cells.

Detailed explanation-4: -Lymphocytes present receptors for antigen (Ag) recognition (TCR and BCR respectively) with different specificities on their surfaces. The genes that encode for these structures undergo a series of DNA recombinations, which provides them with immense phenotypic diversity.

Detailed explanation-5: -The B cells producing the antibodies remember the infection (germ) and provide long-lasting immunity to it. Similarly, T cells can remember viruses that the body has encountered and can make a more vigorous response when they encounter the same virus again.