Video Transcript
The photo provided shows some
lymphocytes in a sample of blood, as viewed under a microscope. The lymphocytes can be identified
as the larger, purple dots. Which of the following statements
correctly describes the difference between phagocytes and lymphocytes? (A) Lymphocytes engulf pathogens to
digest them, whereas phagocytes release antibodies to destroy pathogens. (B) Both lymphocytes and phagocytes
release antibodies to destroy invading pathogens. (C) Phagocytes engulf pathogens to
digest them, whereas lymphocytes release antibodies to destroy pathogens. (D) Phagocytes target specific
pathogens only, but lymphocytes target all the invading pathogens.
To answer this question, we first
need to understand what phagocytes and lymphocytes are and how they function in the
blood. Let’s first clear the answer
choices so we have more room to work with.
Phagocytes and lymphocytes are
found in the blood. They are both types of white blood
cells which fight infection. However, the way they target and
attack pathogens is very different. Phagocytes can engulf pathogens in
a process called phagocytosis. Once inside the phagocyte, the
pathogen is broken down and dies. Lymphocytes can protect the body
from infection by releasing antibodies. Antibodies are molecules that
attach to pathogens and signal to the immune system that these must be
destroyed. Both phagocytes and lymphocytes are
able to target a wide range of pathogens. This way the body is able to fight
off most infections.
Now let’s bring back the answer
choices to see which is the best choice. We can see that answer choice (A)
is incorrect because it’s phagocytes that engulf pathogens, while lymphocytes
release antibodies. This is reversed. Answer choice (B) is incorrect,
because phagocytes don’t release antibodies to destroy pathogens. Answer choice (C) seems to be
correct, because phagocytes engulf pathogens and lymphocytes release antibodies to
destroy pathogens. But let’s look at the final answer
choice to be sure. Answer choice (D) is incorrect. Both phagocytes and lymphocytes can
target a wide range of pathogens.
Therefore, the correct answer is
(C); phagocytes engulf pathogens to digest them, whereas lymphocytes release
antibodies to destroy pathogens.
