Chapter 12, Problem 1Q

A microorganism carries _____ markers and a B cell carries _____ markers.

1. a. self, nonself
2. b. nonself, self
3. c. self, self
4. d. nonself, nonself

Summary Introduction

Introduction:

The immune system evaluates cells by examining a few molecules on their surfaces termed as markers. These markers, which consist of proteins or sugars, allow the cells of the immune system to identify whether the newly discovered cell poses a threat.

Answer to Problem 1Q

Correct answer:

A microorganism carries non-self markers and a B cell carries self-markers. Therefore, option (b) is correct.

Option (b) is given as “nonself, self”.

Explanation of Solution

Justify the reasons for the correct statement:

A microorganism or any foreign particle carries nonself markers so that it can be distinguished from the native cells. B cells carry self-markers so that the immune system can differentiate between native and non-native cells.

Hence, option (b) is correct.

Justify the reasons for the incorrect statements:

Option (a) is given as “self, nonself”.

A microorganism carries nonself markers and a B cell carries self-markers. Hence, it is a wrong answer.

Option (c) is given as “self, self”.

A microorganism doesn’t carry self-markers and a B cell carries self-markers. Hence, it is a wrong answer.

Option (d) is given as “nonself, nonself”.

A microorganism carries nonself markers and a B cell does not carry nonself markers. Hence, it is a wrong answer.

Hence, options (a), (c) and (d) are incorrect.

Conclusion

A microorganism carries non-self-markers and a B cell carries self-markers