Chapter 34. Chapter 34

Problem-Solving Video Assessment

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Chapter 34 Problem-Solving Video Assessment

1.

Scientists perform an antibody-antigen binding assay in the lab. They add various known quantities of antibody to 250 μM of isolated protein antigen and measure the fraction of antigen that is bound to antibody at each antibody concentration. Using this assay, the scientists determine that the K_d for this immune complex is 5.5 x 10^-8 M. When the antibody concentration is equal to K_d, what quantity of antigen is bound to antibody?

2.75 x 10^-8 M

5.5 x 10^-8 M

1.25 x 10^-4 M

2.5 x 10^-4 M

0.125 M

_feedback_correct: Correct. _feedback_incorrect: Incorrect.

2.

Researchers would like to use rabbits to make an antibody against a coat protein from influenza virus. They inject the rabbits with purified coat protein, isolate the resulting antibodies, and test the affinity of antibody-antigen binding; the results are below. Estimate the dissociation constant K_d for the antibody-coat protein complex:

-6.5 M

1.0 x 10^-4 M

1.0 x 10^-7 M

3.2 x 10^-7 M

0.95 M

_feedback_correct: Correct. _feedback_incorrect: Incorrect.

3.

Which of the following statements about antibody generation and diversity is correct?

The uniqueness of each antibody arises in part from V(D)J-segment recombination that forms the constant region of both the light and heavy antibody chains.

There is a very small germ-line repertoire of possible V, D, and J genes.

Antibody diversity arises from somatic recombination of the light-chain genes, while all antibodies of the same class contain identical heavy chains.

Because the immune response is very rapid, recombined antibody genes rarely have time to undergo additional mutation.

Variety within the variable domain of the light and heavy chains is due to a combination of genetic diversity in the germ line, rearrangement and recombination during B-cell maturation, and somatic mutation after recombination.

_feedback_correct: Correct. _feedback_incorrect: Incorrect.

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Chapter 34. Chapter 34

Introduction

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