2022
AP
®
Biology
Sample Student Responses
and Scoring Commentary
Inside:
Free-Response Question 6
•
•
•
• Scoring Guidelines
• Student Samples
• Scoring Commentary
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AP® Biology 2022 Scoring Guidelines
Question 6: Analyze Data
4 points
Researchers are studying the use of RNA vaccines to protect individuals against certain diseases. To develop
the vaccines, particular cells are first removed from an individual. Then
mRNAs
coding for specific proteins
from a pathogen are introduced into the cells. The altered cells are injected back into the individual, where
the cells make the proteins encoded by the introduced mRNAs. The individual then produces an immune
response to the proteins that will help to protect the individual from developing a disease if exposed to the
pathogen in the future.
When introduced into cells, the
mRNAs
used for vaccines must be stable so that they are not degraded
before the encoded proteins are produced. Researchers developed several modified caps that they
hypothesized might make the introduced
mRNAs
more stable than
mRNAs
with the normal GTP cap. To
test the effect of the modified caps, the researchers produced
mRNAs
that
differed only in
their cap
structure
(no
cap, the normal cap,
or m
odified caps
I
,
II
, or
III
).
They
introduced the same
amount of
each
mRNA to
different groups
of cells and
measured the amount of time required for half of
the
mRNAs
to
degrade (mRNA
half-life) and the total amount
of protein translated from the
mRNAs
(Table 1).
TABLE 1. EFFECT OF mRNA CAP STRUCTURE ON mRNA HALF-LIFE AND PROTEIN
TRANSLATED FROM THE INTRODUCED mRNA
5
′
Cap Structure
mRNA Half-Life
±2S E
X
(hours after introduction into cells)
Total A
mount of Protein Translated
from
mRNA
±2S E
X
(relative to amount in normal cap)
No
cap
1.41 ± 0.02 0.011 ± 0.000
Normal GTP cap 16.10 ± 1.83 1.000 ± 0.007
Modified cap
I
15.50 ± 1.57 4.777 ± 0.042
Modified cap
II
27.00 ± 2.85 13.094 ± 0.307
Modified cap
III
18.09 ± 0.81 6.570 ± 0.075
(a)
Based on the data, identify which cap structure is most likely to protect the end of the
mRNAs
from degradation.
• Mo
dified cap
II
1 point
(b)
Based on the data for the
mRNAs
with modified caps, describe the relationship
between the mRNA half-life and the total amount of protein produced.
Acc
ept one of the following:
• A longer mRNA half
-life is associated with more protein.
• There is a positive correlati
on/relationship.
1 point
(c)
After examining the data on mRNA half-lives and the amount of protein produced, the
researchers hypothesized that each mRNA molecule with modified cap I was translated
more frequently than was each mRNA molecule with the normal GTP cap. Evaluate their
hypothesis by comparing the data in Table 1.
• The data suppo
rt their hypothesis because the half-lives of the two
mRNAs
are the
same, but the amount of protein produced from the mRNA with modified cap
I
is
more than (four times as much as) that produced from the mRNA with the normal
cap.
1 point
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AP® Biology 2022 Scoring Guidelines
(d) Introduction of
mRNAs
into cells allows the cells to produce foreign proteins that they
might not normally produce. Explain why the production of a foreign protein may be
more likely from the introduction of mRNA than DNA into cells.
Accept one of the following:
• Protein production from the DNA requires (
transcription) factors to initiate
transcription.
• Protein production from the mRNA does not depend on (correct posttranscriptional)
processing of the pre-mRNA.
• The cells may be unable to transcribe the DNA (while mRNA can be directly
translated).
1 point
Total for question 6 4 points
© 2022 College Board
Q6 Sample A 1 of 2
Q6 Sample A 2 of 2
Q6 Sample C 1 of 1
AP
®
Biology 2022 Scoring Commentary
Question 6
Note: Student samples are quoted verbatim and may contain spelling and grammatical errors.
Overview
Q
uestion 6 described research aimed at developing RNA vaccines. A data table presented the half-life of
mRNAs
with various cap structures, as well as the total amount of protein translated from each mRNA.
Responses to part (a) were expected to identify modified cap
II
as the cap
structure most likely to
protect mRNA
from
degradation (Science Practice
4.B).
Responses to part (b) were expected to describe a positive correlation between mRNA half-
life and total amount
of protein translated (Science Practice 4.B).
Part
(
c) described the researchers’ hypothesis that “each mRNA molecule with modified
cap
I
was translated
more frequently than was each mRNA molecule with the normal GTP
cap.” Responses were expected to
make the
evaluation that the data
supported the hypothesis because the two
mRNAs
did not differ in half-life, but the
amount of translated protein from mRNA with modified cap
I
was higher than that from mRNA with the normal
GTP cap (Learning Objective IST-1.O).
Responses to part (d) were expected to explain that cells are more likely to produce foreign proteins from introduced
mRNA than from introduced DNA because the mRNA can be directly translated, while the cell may not be able to
transcribe the DNA or correctly process the transcripts produced from the introduced DNA (Learning Objective IST-
2.C).
Sample: 6A
Sco
re: 4
The response earned 1 point in part (a) for identifying modified cap
II
. The response earned 1 point in part (b) for
describing that a longer half-life is associated with “more protein … translated from the mRNA.” The response
earned 1 point in part (c) for evaluating that the hypothesis is correct and the half-lives of the two
mRNAs
are
statistically identical and the amount of protein produced by the mRNA with modified cap
I
is greater. The
response earned 1 point in part (d) for explaining that mRNA resulting from transcribing the DNA “might be
spliced, preventing the protein from being produced.”
Sample: 6B
Sco
re: 3
The response earned 1 point in part (a) for identifying modified cap
II
. The response earned 1 point in part (b) for
describing the relationship as “positive.” The response did not earn a point in part (c) because the response
incorrectly states that the half-life of the mRNA with the normal GTP cap was greater than that of the mRNA with
modified cap
I
. The response earned 1 point in part (d) for explaining that, after transcription from introduced DNA,
pre-mRNA processing “may not produce the mature mRNA strand” encoding the intended foreign protein.
Sample: 6C
Sco
re: 2
The response earned 1 point in part (a) for identifying modified cap
II
. The response earned 1 point in part (b) for
describing that the “larger” half-life is associated with more protein produced. The response did not earn a point in
part (c) because, while the response says that the amount of protein produced from modified cap
I
was more, the
response does not state that the hypothesis was supported and that the half-lives of the two
mRNAs
are the same.
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AP
®
Biology 2022 Scoring Commentary
Question 6 (continued)
The response did not earn a point in part (d) because the response does not explain that the cells might be unable to
transcribe the DNA or process mRNA transcribed from the DNA.
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isit College Board on the web: collegeboard.org.