AP Biology. Sample Student Responses and Scoring Commentary. Inside: Free Response Question 6. Scoring Guideline. Student Samples. Scoring Commentary

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1 2018 AP Biology Sample Student Responses and Scoring Commentary Inside: Free Response Question 6 RR Scoring Guideline RR Student Samples RR Scoring Commentary College Board, Advanced Placement Program, AP, AP Central, and the acorn logo are registered trademarks of the College Board. AP Central is the official online home for the AP Program: apcentral.collegeboard.org

2 AP BIOLOGY 2018 SCORING GUIDELINES Question 6 Cystic fibrosis is a genetic condition that is associated with defects in the CFTR protein. The CFTR protein is a gated ion channel that requires ATP binding in order to allow chloride ions (Cl ) to diffuse across the membrane. (a) In the provided model of a cell, draw arrows to describe the pathway for production of a normal CFTR protein from gene expression to final cellular location. Drawing (1 point) The response must follow this pathway: nucleus/nuclear envelope endoplasmic reticulum Golgi apparatus plasma membrane. The response may be in the form of a continuous arrow or multiple discontinuous arrows. (b) Identify the most likely cellular location of the ribosomes that synthesize CFTR protein. Identification (1 point) (Rough) Endoplasmic Reticulum/ER (c) Identify the most likely cellular location of a mutant CFTR protein that has an amino acid substitution in the ATP-binding site. Identification (1 point) In the (cellular/plasma) membrane

3 6. Cystic fibrosis is a genetic condition that is associated with defects in the CFTR protein. The CFfR protein is a J, t d ion channel that requires ATP binding in order to allow chloride ions (Cl -) to diffuse across the m mbrane. the provided model of a cell, draw arrows to describe the pathway for production of a nonnal CFTR otein from gene expression to final cellular location. ('e{j entify the most likely cellular location of the ribosomes that synthesize CFfR protein. J Identify the most likely cellular location of a mutant CFrR protein that has an amino acid substitution in the ATP-binding site. PAGE FOR ANSWERING QUESTION 6 Plasma Membrane Mitochondrion Golgi Apparat11s Lysosome Endoplasmic Reticulum _ Yf) TicL n y.;o-o: 6(Y.,,5 oro 0-k BLJ n <ih.l& 7'2te... c t=-d 'L Ji)_J /1) ¾A<n 'f'i(t\()c\ 12):0:)}()L,,0 DL W-:\YO d oo Ck<,.2 Sb \) if 1iJ- I Unauthorized copying or reuse of any par! of this page Is Illegal GO ON TO THE NEXT PAGE.

4 6. Cystic fibrosis is a genetic condition that is associated with defects in the CFfR protein. The CFfR protein is a gated ion channel that requires ATP binding in order to allow chlo1ide ions (CJ-) 10 diffuse across the membrane. (a) (b) Identify the most likely cellular location of the ribosomes that synthesize CFTR protein. (c) In the provided model of a cell, draw arrows to describe the pathway for production of a nom1al CPTR protein from gene expression to final cellular location. Identify the most likely cellular location of a mutant CFTR protein that has an amino acid substitution in the ATP-binding site. lob PAGE FOR ANSWERING QUESTION 6 Plasma Membrane Mitochondrion Golgi Apparatus Lysosome Endoplasmic Reticulum Unauthorized copying or reuse of any part of this page Is lllogal GO ON TO THE NEXT PAGE.

5 6. Cystic fibrosis is a genetic condition that is associated with defects in the CFrR protein. The CFrR protein is a gated ion channel that requires ATP binding in order to allow chloride ions (CJ-) to diffuse across the membrane. (a) In the provided model of a ccji, draw arrows to describe the pathway for production of a nonnal CFfR protein from gene expression to final cellular location. (b) Identify the most likely cellular location of the ribosomes that synthesize CFTR protein. (c) Identify the most likely cellular location of a mutant CFrR protein that has an amino acid substitution in the ATP-binding site. PAGE FOR ANSWERING QUESTION 6 Plasma Membrane Milochond:rion Golgi Apparatus Lysosome Endoplasmic Reticulum b')-+1r-t. r;0060dl'o:..'> 1:::½M.t t>,/.ri'\--l,,-4'>:c C.}TY!. da,,.<. N'O\t 1,'ke...t{ CD, i:,tjt.d r o +0:<. '\Qopltt;JMi"c rlc+0:0iu/v\ e,,) Mn:hID:r CED1 pr:0l1;0 ldk<t,4 ou,vo V\/?--0,... /.¼ mi a'n t{,,!: ln td '2 A-TQ t9 XjP.HYL 'Z 12 Unauthorized copying or reuse of any part of this pago Is Illegal GO ON TO THE NEXT PAGE.

6 AP BIOLOGY 2018 SCORING COMMENTARY Question 6 Overview This question presented students with information about CFTR, a gated ion channel that requires ATP binding to allow ions to diffuse across the plasma membrane. Students were shown a diagram of a cell with numerous subcellular structures drawn and labeled. Students were asked to draw arrows to describe the pathway for production of a CFTR protein from gene expression to final location in the cell. The students were then asked to identify the most likely cellular location of the ribosomes that synthesize this protein. The question then provided information about a particular mutation in the CFTR protein, and students were asked to identify the most likely final cellular location of that protein. The key understandings and skills students were expected to demonstrate included the following: Knowledge of subcellular structures and organelles was used to predict the process of synthesizing a specific protein. Knowledge of protein domains was used to determine the impact of mutations on the structure and function of a protein. Representations and models were used to describe the interactions of cellular organelles and to predict the consequences of a mutation. Sample: 6A Score: 3 The response earned 1 point in part (a) for correctly describing the pathway for the production of a normal CFTR protein with arrows. The response earned 1 point in part (b) for identifying the rough ER as the most likely cellular location of the ribosomes that synthesize the CFTR protein. The response earned 1 point in part (c) for correctly identifying that the most likely cellular location of a mutant CFTR protein is embedded in the plasma membrane. Sample: 6B Score: 2 The response earned 1 point in part (a) for correctly describing the pathway for the production of a normal CFTR protein with a single continuous arrow. The response earned 1 point in part (b) for identifying the rough endoplasmic reticulum as the most likely cellular location of the ribosomes that synthesize CFTR protein. Sample: 6C Score: 1 The response earned 1 point in part (b) for identifying the endoplasmic reticulum as the most likely cellular location of the ribosomes that synthesize CFTR protein.