2002ScoringGuidelines - AP® Biology 2002 Scoring...

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Unformatted text preview: AP® Biology 2002 Scoring Guidelines The materials included in these files are intended for use by AP teachers for course and exam preparation in the classroom; permission for any other use must be sought from the Advanced Placement Program®. Teachers may reproduce them, in whole or in part, in limited quantities, for face-to-face teaching purposes but may not mass distribute the materials, electronically or otherwise. These materials and any copies made of them may not be resold, and the copyright notices must be retained as they appear here. This permission does not apply to any third-party copyrights contained herein. These materials were produced by Educational Testing Service® (ETS®), which develops and administers the examinations of the Advanced Placement Program for the College Board. The College Board and Educational Testing Service (ETS) are dedicated to the principle of equal opportunity, and their programs, services, and employment policies are guided by that principle. The College Board is a national nonprofit membership association dedicated to preparing, inspiring, and connecting students to college and opportunity. Founded in 1900, the association is composed of more than 4,200 schools, colleges, universities, and other educational organizations. Each year, the College Board serves over three million students and their parents, 22,000 high schools, and 3,500 colleges, through major programs and services in college admission, guidance, assessment, financial aid, enrollment, and teaching and learning. Among its best-known programs are the SAT®, the PSAT/NMSQT®, and the Advanced Placement Program® (AP®). The College Board is committed to the principles of equity and excellence, and that commitment is embodied in all of its programs, services, activities, and concerns. Copyright © 2002 by College Entrance Examination Board. All rights reserved. College Board, Advanced Placement Program, AP, SAT, and the acorn logo are registered trademarks of the College Entrance Examination Board. APIEL is a trademark owned by the College Entrance Examination Board. PSAT/NMSQT is a registered trademark jointly owned by the College Entrance Examination Board and the National Merit Scholarship Corporation. Educational Testing Service and ETS are registered trademarks of Educational Testing Service. AP® BIOLOGY 2002 SCORING GUIDELINES Question 1 1. (a) ● Maximum 4 points for this part of the question (1 point earned for each bullet below, up to 4) (Maximum 3 points, 1 for each bullet) Describe the use of plasmid for cloning/sequencing a human gene • Cut plasmid with “restriction” enzyme • Cut/isolate human sequence with the corresponding “restriction” enzyme • Mix/anneal/ligate • Introduce recombinant plasmid into bacteria • Select recombinant bacteria (e.g., antibiotic resistance, fluorescence, reporter gene, etc.) • Bacterial reproduction used to amplify the sequence • Describe either degradative (Maxam-Gilbert) or dideoxy (Sanger) method to generate fragments • Electrophoresis to separate fragments • Read the sequence (automated method is OK) (Maximum 3 points, 1 for each bullet) Explain the contribution of this procedure • Source of the DNA is immaterial to cloning • Used to produce transgenic organisms • Used to make human proteins (e.g., insulin, HGH) • Understanding gene structure/regulation • Comparative genomics • Development of gene therapies • Making gene library • Amplifying a particular sequence ● Maximum 4 points for this part of the question (1 point earned for each bullet below, up to 4) (Maximum 3 points, 1 for each bullet) Describe PCR • Heat to separate strands • Add primers • Cool to anneal • Add polymerase and/or nucleotides • Specification of heat stable (Taq) polymerase • Description of thermocycling process • Repetition of process Copyright © 2002 by College Entrance Examination Board. All rights reserved. Advanced Placement Program and AP are registered trademarks of the College Entrance Examination Board. 2 AP® BIOLOGY 2002 SCORING GUIDELINES Question 1 (cont’d.) (Maximum 3 points, 1 for each bullet) Explain the contribution of this procedure • Allows amplification of very small samples • Replicates/amplifies a defined region • Can be automated to allow for faster expansion of knowledge • Can be used for forensics • Can be used for diagnosis • Evolutionary applications • Other • Maximum 4 points for this part of the question (1 point earned for each bullet below, up to 4) (Maximum 3 points, 1 for each bullet) Describe RFLP analysis • DNA sample cut with “restriction” enzyme(s) • Separation of fragments (electrophoresis) • Description/elaboration of electrophoresis (charge/size/apparatus) • Visualize fragments (probes, dyes, blots) • Compare fragment sizes/mobility • Compare single and double digests (two or more restriction enzymes) • Compare individuals/species/organisms/tissue samples (Maximum 3 points, one for each bullet) Explain the contribution of RFLP analysis • Trace RFLPs as genetic markers in families • Diagnose disease/carriers/prenatal samples • Prepare fingerprints (for forensics, etc.) • Order fragments for physical mapping • Compare genomes of different species/evolutionary relationships • Locate the flanking regions of the gene/sequence • Find mutations • Individual bands can be used for further analysis • Can determine presence of sequence without knowing its function Copyright © 2002 by College Entrance Examination Board. All rights reserved. Advanced Placement Program and AP are registered trademarks of the College Entrance Examination Board. 3 AP® BIOLOGY 2002 SCORING GUIDELINES Question 1 (cont’d.) 1. (b) Maximum 4 points — Explain the contradiction Sources of difference in DNA fingerprint • Variation in non-coding material (introns, spacers, minisatellites, “junk,” transposable elements) • Point mutations, small deletions, SNPs (single NT polymorphisms) • Variable number of tandem repeats (VNTRs/STRs) Recognition of differences • A small percentage difference of a very large genome results in a large number of nucleotide differences • PCR-based fingerprinting: differences found by where primers anneal • Variation in restriction enzyme cutting sites Similarities among proteins • Redundancy in the code for amino acids • Neutral/silent mutation does not alter the function of the protein Caution: No explanation points in (a) without an attempted description of procedure Order of procedure points is not important if they are logical and accurate No credit for mutations leading to new phenotypes Codons specify amino acids (not proteins) Copyright © 2002 by College Entrance Examination Board. All rights reserved. Advanced Placement Program and AP are registered trademarks of the College Entrance Examination Board. 4 AP® BIOLOGY 2002 SCORING GUIDELINES Question 2 2. (a) A maximum of 5 points Description of the cycle of activity (1 point) A student could earn a point if he/she accurately summarized the graph. A simplistic statement such as, “Bombats are active during the day and quiet at night” which ignored the shape and obvious peaks and valleys of the graph did not receive the point. To earn this point, the student had to identify the peak of activity at “noon,” “midday,” or “12:00 p.m.,” AND indicate a lower activity at “night.” The student could also be specific about the lowest activity being at “midnight,” or “12:00 a.m.” The description had to be clearly distinguishable from the rest of the answer and not simply implied in another part of the response. Discussion of how THREE factors might affect the physiology and/or behavior resulting in the cyclic activity pattern (1 point each) To earn points here, each of the descriptions had to (a) be biologically plausible and consistent with typical mammalian behavior and physiology (no fictional biology); (b) indicate a cause and effect relationship beyond a simple restatement of the question. This had to include at least a very brief indication of how or why the factor had any effect at all on the bombat — or in some cases its prey; and finally, the discussion could not be inconsistent with the part of the curve described or time of day referenced in the explanation. Elaboration on any one of the three factors (1 point) Here the readers were looking for exemplary descriptions of physiology and/or behavior that reflected an unusual depth of understanding and clarity of expression. With special regard to temperature, a student who demonstrated an understanding that the activity curve was different from a temperature curve or that mammal physiology, unlike that of ectotherms, is typically insensitive to temperature could earn an elaboration point. 2. (b) A maximum of 7 points Hypothesis (1 point) The student was required to indicate that a CHANGE in the light (intensity, duration, wavelength) causes a CHANGE in the cycle of activity or biorhythm. There also could be a prediction of a change of light having no effect on the cycle of activity. Like the description of the curve above, the hypothesis statement had to be clearly distinguishable from the rest of the answer and not simply implied in another part of the response. The student may have failed to earn this point if the experiment he/she designed below clearly used a different light characteristic (independent variable), and/or produces a different result (dependent variable) from the ones indicated in his/her hypothesis. Copyright © 2002 by College Entrance Examination Board. All rights reserved. Advanced Placement Program and AP are registered trademarks of the College Entrance Examination Board. 5 AP® BIOLOGY 2002 SCORING GUIDELINES Question 2 (cont’d.) Experimental Design (5 points maximum) If the experimental design used a factor other than light for the independent variable, AND it satisfies AT LEAST THREE of the following standards, the answer was still allowed to earn 1 point total for this and the “Description of Results” section combined. 1 point Specified an appropriate control group for comparison. In this control, the environmental conditions had to be very similar to the natural conditions in which you find the bombat population, and not simply placing them into the dark, etc. 1 point Indicated that the independent variable (light) was manipulated. This was usually a change in light intensity or photoperiod. 1 point Held confounding variables constant or indicated that all variables other than the independent variable are held constant. To earn the point for listing the variables being held constant, the student had to list at least two. 1 point Verified results with reasonable sample size (at least two bombats in each group), and/or repeated trials. With repeated trials, the point was not awarded if the same bombat was used over and over. 1 point “Measured,” “recorded,” etc. (using quantitative terminology) bombat activity levels (dependent variable). If the student used the verb “observe,” then some measurement activity had to be specified. 1 point Included a mathematical and/or statistical comparison of control and experimental groups, or of observed and expected results. A specific kind of inferential statistic (chi square, t-test, etc.) did not need to be mentioned. A comparison of slopes of curves on a graph was also acceptable. Description of results (1 point) If the student had earned AT LEAST 3 POINTS in the Experimental Design section above, he/she became eligible for 1 point earned for a graph, data table and/or description of results consistent with the experimental design. Copyright © 2002 by College Entrance Examination Board. All rights reserved. Advanced Placement Program and AP are registered trademarks of the College Entrance Examination Board. 6 AP® BIOLOGY 2002 SCORING GUIDELINES Question 3 Points can be awarded for three categories: Structure/function, Description, and Adaptive value. • 1 point awarded for correct structure linked to its function. Maximum is 6 points with only 1 point given per phylum per process. • 1 point awarded for elaborate description of the structure if the related structure/function is correct and appropriate. This cannot be a single word. Maximum is 3 points. • 1 point awarded for adaptive value linked to structure. This value should clearly establish a selective advantage. Maximum is 3 points. 1 point maximum may be awarded for natural selection being used throughout all phyla but it must still be coupled to a correct structure. Process I Cnidaria Annelida Chordata Process II 1 point Structure + Function 1 point Structure + Function 1 point Structure + Function 1 point Structure + Function 1 point Structure + Function 1 point Structure + Function Elaborate Description (I or II) (3 points maximum) 1 point (only with 1 point proper structure 1 point + function link) Adaptive Value (3 points maximum) 1 point (only when 1 point linked with 1 point proper structure) TRANSPORT OF MATERIALS (has to be a mover of nutrients, oxygen, wastes, hormones, gametes, chemicals) Cnidarians Structure Function Description Molecular level Amebocytes/ gastrodermal cell Undergo phagocytosis Mobile cells found in mesoglea GVC Circulates water and nutrients Fluid-filled/extends into tentacle/hollow cavity/ digestive sac with one opening Circulatory canal Connects all branches of canals, circulates gametes Cilia Keeps fluids moving Adaptive Value (tied to structure) Nutrient transport to body surface * Importance of material transport * Maintain optimal concentration gradients, permits for larger body size and complexity Tiny hairs * This represents an answer that can be connected to any structure(s) option. Copyright © 2002 by College Entrance Examination Board. All rights reserved. Advanced Placement Program and AP are registered trademarks of the College Entrance Examination Board. 7 AP® BIOLOGY 2002 SCORING GUIDELINES Question 3 (cont’d) Annelids Structure Function Description Adaptive Value (tied to structure) * Importance of material transport Molecular level Membranes – nephridia, typhlosole, capillary Method of transport needs to be specific (diffusion/ facilitated/active) Semi-permeable, transport proteins, elaborate description of structure System level – (mover must be named) circulatory digestive reproductive respiratory* not to include same examples as in gas exchange Tissue or organ must have function related to material being transported Examples: aortic arch/pseudoheart, muscular activity, muscular contraction Tissue or organ must be described to show how structure relates to function. Example, dorsal, ventral, segmental, conducting tubes, muscular, five pairs * Maintain optimal concentration gradients, permits for larger body size and complexity Description Adaptive Value (tied to structure) * Importance of material transport Chordates Structure Function Molecular level Membranes – nephron, villi, capillary Method of transport needs to be specific (diffusion/ facilitated/active) Semi-permeable, transport proteins, elaborate description of structure System level(mover must be named) circulatory digestive reproductive respiratory* not to include same examples as in gas exchange lymphatic excretory Tissue or organ must have function related to material being transported Examples: pumping heart, peristalsis by muscular activity, diaphragm contracting, gular movement in frogs, uterine contractions, muscle contraction Tissue or organ must be described to demonstrate how structure relates to function. * Maintain optimal concentration gradients, permits for larger body size and complexity * This represents an answer that can be connected to any structure(s) option. Copyright © 2002 by College Entrance Examination Board. All rights reserved. Advanced Placement Program and AP are registered trademarks of the College Entrance Examination Board. 8 AP® BIOLOGY 2002 SCORING GUIDELINES Question 3 (cont’d) RESPONSE TO STIMULI (detection, transmission, and/or effector) Two of these must be present. Cnidarians Structure Receptor Function Detects stimulus and transmits Nerve net/ ring Detects stimulus and transmits or transmits + responds Contractile fiber/cell Description Must demonstrate how structure relates to function Tentacle movement /body contraction Nematocyte Cnidocyte Cnidoblast Nematocyst Stinging cell stinging tentacle Annelids Structure Sensory receptor Adaptive Value Radial symmetry allows for multidirectional response/coordinated response *Prey capture and defense Stings prey/toxic or poisonous, defense Function Detects stimulus and transmits Description Photo, tactile, chemo Adaptive Value *More complex behavior Special segments Integration/ transmission Cephalized, anterior, or paired bundles of nerves *Directed response Ganglia/brain Integration/ transmission Rudimentary/primitive Complex locomotion Nerve cord Segmental control Ventral or paired bundles of nerves/segmented nerves Effector organ/ structure (gland, muscle, setae, reproductive) Contraction/ movement/secretion Proper description Copyright © 2002 by College Entrance Examination Board. All rights reserved. Advanced Placement Program and AP are registered trademarks of the College Entrance Examination Board. 9 AP® BIOLOGY 2002 SCORING GUIDELINES Question 3 (cont’d) Chordates Structure Sensory receptor Function Detects stimulus and transmits Description Photo, chemo, auditory, equilibrium, touch, tactile, olfactory Adaptive Value *Improved homeostasis Spinal/nerve cord Integration/ transmission Dorsal/hollow *More complex behavior Brain Integration/ transmission Specialized regions/complex *Directed response Effectors Contraction, movement, secretion Proper description GAS EXCHANGE (diffusion of oxygen and carbon dioxide) Cnidarians Structure Body wall/outer epithelium/ epidermis or gastrovascular cavity (GVC) Description 2 layers thick Adaptive Value *Increased surface area Fluid-filled, continuous with outside water *Increased rate of exchange Function Diffusion of O2 and CO2 / moving toward [ ↓ ] Description Moist, thin, vascularized — (MUST HAVE TWO) Adaptive Value *Increased surface area Parapodia Diffusion of O2 and CO2 / moving toward [ ↓ ] Must demonstrate understanding of how structure relates to function *Increased oxygen/ carbon dioxide exchange efficiency/rate of exchange Gills Diffusion of O2 and CO2 / moving toward [ ↓ ] Must demonstrate understanding of how structure relates to function Hemoglobin/ other respiratory pigment Carries oxygen/ carbon dioxide Respiratory pigment/ transport protein Annelids Structure Skin/integument/epidermis /epithelium Function Diffusion of O2and CO2 / moving toward [ ↓ ] * This represents an answer that can be connected to any structure(s) option. Copyright © 2002 by College Entrance Examination Board. All rights reserved. Advanced Placement Program and AP are registered trademarks of the College Entrance Examination Board. 10 AP® BIOLOGY 2002 SCORING GUIDELINES Question 3 (cont’d) Chordates Structure Gills/ lamellae Function Diffusion of O2+CO2 / moving toward [↓ ] Countercurrent exchange Description Must demonstrate understanding of how structure relates to function (example, sheet-like, flat, vascularized ) Adaptive Value *Increased surface area Modified swim bladder Diffusion of O2+ CO2 / moving toward [ ↓ ] Examples: sac pouch connected to pharynx *Internalization to avoid dehydration/ damage Skin (amphibian) Diffusion of O2+CO2 / moving toward [ ↓ ] Examples: moist and vascularized *Increased oxygen/ carbon dioxide exchange efficiency/ rate of exchange Lung/alveoli Diffusion of O2+CO2 / moving toward [ ↓ ] Examples: compartmentalized lung/ vascularized alveoli/ alveolar sacs/ membranous sac Avian supplemental air sacs Diffusion/ moving toward [ ↓ ] Hemoglobin/ RBC Carries oxygen/ carbon dioxide Respiratory pigment/ transport protein * This represents an answer that can be connected to any structure(s) option. Copyright © 2002 by College Entrance Examination Board. All rights reserved. Advanced Placement Program and AP are registered trademarks of the College Entrance Examination Board. 11 AP® BIOLOGY 2002 SCORING GUIDELINES Question 3 (cont’d) LOCOMOTION (move organism from point A to point B) Cnidarians Structure Hydrostatic skeleton with contractile fibers (muscles) Function Contractile fibers/ muscle acting on hydrostatic skeleton to move organism Description Concept of hydrostatic GVC Contractile fibers/ muscle acting on hydrostatic skeleton to move organism Fluid-filled cavity Contractile fibers/muscle Tumbling, somersaulting, looping, floating (with explanation) Cilia on larvae (planulae) Swimming Tiny hair-like Dispersion Function Contractions allow for shortening/ lengthening of body Directed movement Description Concept of hydrostatic Longitudinal, circular, segmental Adaptive Value *Oriented response Skin Mucous aids in movement Mucous used as a lubricant *Food gathering, improved mobility Suckers Anchoring Setae, Parapodia, lateral flaps Pushing, burrowing, anchoring, acting against resistance Bristles, flap-like, paddlelike Cilia on larva (trochophore) Swimming Tiny hair-like Annelids Structure Hydrostatic skeletal/coelom with muscles OR muscles + fluidfilled cavity Adaptive Value *Expands food gathering options, avoidance, promotes gene flow Dispersion, predator avoidance * This represents an answer that can be connected to any structure(s) option. Copyright © 2002 by College Entrance Examination Board. All rights reserved. Advanced Placement Program and AP are registered trademarks of the College Entrance Examination Board. 12 AP® BIOLOGY 2002 SCORING GUIDELINES Question 3 (cont’d) Chordates Structure Skeleton and muscles Function Movement associated with muscle contraction Description Muscles attached to bone/endoskeleton, cartilage Adaptive Value *Efficient, predator/prey interaction, food gathering *Promotes gene flow, sexual selection, habitat selection * This represents an answer that can be connected to any structure(s) option. Copyright © 2002 by College Entrance Examination Board. All rights reserved. Advanced Placement Program and AP are registered trademarks of the College Entrance Examination Board. 13 AP® BIOLOGY 2002 SCORING GUIDELINES Question 4 4. (a) 3 points maximum 1 point 1 point correct axes labels with units and scaling for 5% line on axes provided 1 point 4. (b) correct orientation with dependent variable (concentration) on y (vertical) axis and independent variable (time) on x (horizontal) axis correct plotting of all data points including zero (0,0); line is not necessary but if drawn must not extend beyond last data point; dashing line beyond last data point is okay; arrow at end of line is okay 4 points maximum 1 point correct prediction and legend (or label) for 0%, 1%, and 10% lines (0% line flat, 1% line below 5% line, 10% line above 5% line) Explanation points 1 point correct explanation for 0% line (e.g., since there is no NaCl in the bag no Na+Cl- can diffuse into the water in the beaker) 1 point correct explanation for 1% line — must include a discussion of rate; connects concentration of NaCl with diffusion rate 1 point correct explanation for 10% line — must include a discussion of rate; connects concentration of NaCl with diffusion rate or 1 point 4. (c) general explanation that solute concentration affects the rate of diffusion; answers that attempt to explain the 0%, 1% or 10 % NaCl lines are not eligible to receive this point 4 points maximum 1 point statement that water will leave the plant and description of effect this has on plant cell (e.g., loss of turgor, plasmolysis, decrease in cell volume, decrease in central vacuole volume) 1 point concept of osmosis (e.g., movement of water across a selectively permeable membrane (cell or cell membrane) from solution with lower solute concentration (hypotonic) to solution with higher solute concentration (hypertonic) 1 point explanation that water moves from solution with higher (more positive/less negative) water potential (ψ) to solution with lower (more negative) water potential (ψ) 1 point explanation of how water loss can cause decreased crop production (e.g., stomates close, transpiration stops, photosynthesis stops, decreased metabolism) Copyright © 2002 by College Entrance Examination Board. All rights reserved. Advanced Placement Program and AP are registered trademarks of the College Entrance Examination Board. 14 ...
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