ap05_sg_biology - AP® Biology 2005 Scoring Guidelines The...

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: AP® Biology 2005 Scoring Guidelines The College Board: Connecting Students to College Success The College Board is a not-for-profit membership association whose mission is to connect students to college success and opportunity. Founded in 1900, the association is composed of more than 4,700 schools, colleges, universities, and other educational organizations. Each year, the College Board serves over three and a half million students and their parents, 23,000 high schools, and 3,500 colleges through major programs and services in college admissions, 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 excellence and equity, and that commitment is embodied in all of its programs, services, activities, and concerns. Copyright © 2005 by College Board. All rights reserved. College Board, AP Central, APCD, Advanced Placement Program, AP, AP Vertical Teams, Pre-AP, SAT, and the acorn logo are registered trademarks of the College Entrance Examination Board. Admitted Class Evaluation Service, CollegeEd, Connect to college success, MyRoad, SAT Professional Development, SAT Readiness Program, and Setting the Cornerstones are trademarks owned by the College Entrance Examination Board. PSAT/NMSQT is a registered trademark of the College Entrance Examination Board and National Merit Scholarship Corporation. Other products and services may be trademarks of their respective owners. Permission to use copyrighted College Board materials may be requested online at: http://www.collegeboard.com/inquiry/cbpermit.html. Visit the College Board on the Web: www.collegeboard.com. AP Central is the official online home for the AP Program and Pre-AP: apcentral.collegeboard.com. AP® BIOLOGY 2005 SCORING GUIDELINES Question 1 Part A: Graph and Optimum Temperature (3 points maximum) Graph Setup (1 point) Must contain: • Title/Legend and Y-axis [Bubbles of gas/Min] • X-axis [Temperature (ºC)] • Correct measurement units and scaling for axes Data Plotted (1 point) • Correctly plotted points in proper orientation • Points may or may not be connected with a line • Bar graph acceptable Optimum Temperature (1 point) • 30º C, or between 20º C and 40º C either clearly indicated on the graph or in a sentence Effect of Temperature on Enzyme Activity 14 Gas Bubbles Produced/ Minute 12 10 8 6 4 2 0 0 Part B: Analyze and Explain the Results (4 points maximum) 20 40 60 Temperature (ºC) Analysis (1 point) • Provide range of the change in respiration activity (increase and decrease) to temperature change (increase and decrease) Explanations (1 point each) • Below optimum—Increase in molecular movement leads to increase in reaction rate • Above optimum—Denaturing of enzymes leads to decrease in reaction rate Elaboration (2 points maximum, 1 point each) • Relating enzyme function (effect on reaction rates) to allosteric site, active site, H+ bond, R groups • Gas production due to respiration (can use either aerobic respiration or fermentation) • Induced fit • Lowering energy of activation • Enzyme specificity Part C: Experimental Design (4 points maximum) NOTE: Experiment must be feasible. Must include sugar solutions of varying pH and an organism. If experiment is not reasonable, no points are awarded in the design structure section below. Design Structures (3 points maximum, 1 point each) • Two experimental constants—constant amounts of yeast or sugar, or temperature held constant • Independent variable tested—reasonable pH range must be stated, including acid through base Copyright © 2005 by College Board. All rights reserved. Visit apcentral.collegeboard.com (for AP professionals) and www.collegeboard.com/apstudents (for AP students and parents). 2 80 AP® BIOLOGY 2005 SCORING GUIDELINES Question 1 (continued) • • • Control—identification of a control treatment, e.g., no sugar, no yeast, pH 7 Measurable product per unit of time—gas production, color change, etc. Multiple trials—repeat trials, several samples, stats, etc. Prediction (1 point) • Designate a pH at which enzymes will function optimally Copyright © 2005 by College Board. All rights reserved. Visit apcentral.collegeboard.com (for AP professionals) and www.collegeboard.com/apstudents (for AP students and parents). 3 AP® BIOLOGY 2005 SCORING GUIDELINES Question 2 Part A (5 points maximum) Component Chromatids Centromere Nucleosome concept Chromatin form (heterochromatin/ euchromatin) Structure: 1 point/component 2/sister/pair/identical DNA/genetic information Noncoding/uncoiled/narrow/constricted region/determines arm ratio Histones, DNA wrapped around special proteins Condensed/supercoiled → Loosely coiled → Kinetochores Genes or DNA Disc-shaped proteins Brief DNA description Telomeres Tips, ends, noncoding repetitive sequences Function: 1 point/component Distribution of one copy to each new cell Joins/holds/attaches chromatids together Packaging compacting Proper distribution in cell division (not during replication) Gene expression during interphase/replication occurs when loosely packed Spindle attachment/alignment Codes for proteins or for RNA Protection against degradation/ aging, limits number of cell divisions NOTE: • No points for just naming the component. • No points for stating that chromosomes are made of genes. • A diagram alone will not suffice but can be used for clarification. Copyright © 2005 by College Board. All rights reserved. Visit apcentral.collegeboard.com (for AP professionals) and www.collegeboard.com/apstudents (for AP students and parents). 4 AP® BIOLOGY 2005 SCORING GUIDELINES Question 2 (continued) Part C (4 points maximum) Part B (4 points maximum, 2 points per theme) • • • • • allows for genetic variation o through independent assortment (brief description) o through crossing over (brief description) o leads to variation in gametes allows for genetic stability o efficiency of transfer of genetic information o prevents loss of genetic information o offspring get same number of chromosomes o maintains integrity of chromosomes o linked genes tend to be inherited together allows for gene regulation o increased complex structure o histone acetylating o methylation allows for complexity o allows for more genes o evolution of new genes can occur/transposons o intron/exon allows for alternate splicing allows for diploid/polyploid o genetic fitness o minimizes the effect of harmful alleles/backup copy o extra set(s) of alleles o heterozygosity • • • • • • • • shape (circular/nonlinear/loop) less complex (no histones/less elaborate structure/folding) size (smaller size/less genetic information/fewer genes) replication method (single origin of replication/theta replication) transcription/translation may be coupled generally few or no introns (noncoding) majority of genome expressed operons—gene regulation No points for plasmids—more common but not unique to prokaryotes/not part of prokaryote chromosome. Copyright © 2005 by College Board. All rights reserved. Visit apcentral.collegeboard.com (for AP professionals) and www.collegeboard.com/apstudents (for AP students and parents). 5 AP® BIOLOGY 2005 SCORING GUIDELINES Question 3 Part A (6 points maximum) NOTE: These examples are not all-inclusive, merely the most frequently encountered. Structure AND Function (1 point) Flower Sexual reproduction Petals Sepals Stamen Attract pollinators Protect developing flower Male reproductive structure/produces pollen Anther (microsporangium) Filament Pollen Produces pollen/male gametophyte Pollen structure Dispersal aid Pollen tube Delivers sperm to ovule Carpel/Pistil Positions anther/pollen to pollinator Packages and delivers male gamete Female reproductive structure/produces ovule/protects embryo Stigma Pollen trap/collector Style Ovary Positions stigma, pollen tube guide Produces/protects ovule/seed dispersal/ fruit Produces female gamete/gametophyte Ovule (megasporangium) Embryo sac Receives sperm nuclei/double fertilization Seed Fruit Nourishes, encloses, protects plant embryo Promotes seed dispersal/protects seed/ seed dormancy Endosperm Nectary Asexual reproduction (vegetative propagation/ cloning) Nourishes embryo Produces nectar Stem modifications/root/leaves Evolutionary Significance (1 point) Increases probability of fertilization Increases genetic diversity Protects embryo Increase probability of pollination Increase probability of reproduction Increases probability of pollination Reproductive isolation/pollen-stigma recognition Increases probability of pollination Increases probability of pollination Increases probability of pollination/ eliminates the need for free water Increases genetic diversity/ variability Increases probability of fertilization Increases survival of embryo Pollen recognition/compatibility/ reproductive isolation Increases probability of pollination pollen recognition/compatibility Increases fertilization rate Increases survival rate Protection of gamete/increased probability of fertilization Protection and development of embryo Increased survivorship of embryos Avoids inbreeding depression/ increased survivorship/ increased dispersal to avoid competition Increased survival of embryo Increases probability of pollination Rapid multiplication of a highly fit phenotype in a stable environment Copyright © 2005 by College Board. All rights reserved. Visit apcentral.collegeboard.com (for AP professionals) and www.collegeboard.com/apstudents (for AP students and parents). 6 AP® BIOLOGY 2005 SCORING GUIDELINES Question 3 (continued) Part B (2 points maximum, 1 point each) • Nonvascular plants—lack of vascular system which limits water uptake and transport, linked to how this limits distribution • Flagellated sperm require water for fertilization, linked to how this limits distribution • Spores (limited nutrient/energy stores)—limited longevity limits dispersal, linked to how this effects distribution • Gametophyte = dominant generation—genetic limitations due to haploidy/sporophyte dependent on gametophyte, thereby limiting distribution Part C (5 points maximum, 1 point each) • Gametophyte AND sporophyte • Haploid/monoploid (n) AND diploid (2n) • Proper dominant generation (1 point max) o sporophyte (2n) in angiosperms o gametophyte (n) in bryophytes • Role of meiosis (1 point maximum) o diploid to haploid o produce spores • Role of fertilization—haploid to diploid • Spores form gametophytes (n) • Elaboration (1 elaboration point maximum) including, but not limited to, the following: o Bryophytes—antheridium/archegonium OR angiosperms—pollen grain or tube/embryo sac o Expand on role of mitosis: spore → mitosis→ gametophyte → mitosis→ gametes; zygote → mitosis → sporophyte Copyright © 2005 by College Board. All rights reserved. Visit apcentral.collegeboard.com (for AP professionals) and www.collegeboard.com/apstudents (for AP students and parents). 7 AP® BIOLOGY 2005 SCORING GUIDELINES Question 4 NOTE: One point is awarded for each bulleted item; maximum of 4 points for each section. Provides an immediate nonspecific immune response (4 points maximum) • • • • • • • • Physical barrier (e.g., skin or mucous membranes [or blood clot]) with explanation that barrier prevents pathogens and parasites from entering the body. Resident microflora prevents pathogen attachment. Saliva, mucous, or tears wash away harmful entities; also vomiting/diarrhea purge harmful agents. Chemical barriers (low pH, salt, fatty acids of skin inhibit microbial growth, antimicrobial agents [e.g., lysozyme kills bacteria by digesting bacterial wall]). Inflammatory response: blood vessels dilate (precapillary arterioles dilate and postcapillary venules constrict), producing redness, edema, heat (fever), pain, and leading to an increase in white blood cells and clotting factors. Chemical agents: i. Interferons from cells infected with viruses stimulate nearby cells to produce chemicals that inhibit viral reproduction, OR chemokines activate monocytes to develop into macrophages. ii. Histamines cause increase in permeability of capillaries with an increased blood flow that results in more clotting and more white blood cells, OR histamines secreted by mast cells, OR prostaglandins increase blood flow. iii. Pyrogens induce fever that inhibits pathogen. Phagocytosis: ingestion by white blood cells (e.g., neutrophils, macrophages, or monocytes ) Lysis of cells: Eosinophils or natural killer cells Complement system: leads to the lysis of microbes, or aids in recruitment of white blood cells. Elaboration of any one of the above (e.g., a second physical or chemical barrier) Activates T and B cells in response to an infection (primary immune response) (4 points maximum) • • • • • • • • • • Macrophages/white blood cells engulf and/or display antigens (may say: epitope) from infection. Antigen-presenting cell binds helper T cells to activate or stimulate helper T cells. Antigen-presenting cell activates or stimulates cytotoxic T cells. Antigen binding to B cell activates B cell. Helper T cell activates/stimulates B cell and/or cytotoxic T cell. Interleukin—1 (from macrophages) activates helper T cells. Interleukin—2 and/or cytokines (from helper T cells) activate B cells or cytotoxic T cells. CD4 on helper T cell enhances binding of helper T with antigen-presenting cell; leads to activated T cells. CD8 on cytotoxic T cell enhances binding and enhances activation of cytotoxic T cell. Elaboration point for explaining one of the following: i. MHC in primary immune response. ii. B (or plasma) cells produce/secrete antibody. iii. Cytotoxic T cells destroy infected cells. iv. Antibody mechanism of action (i.e., neutralization/agglutination/precipitation). Copyright © 2005 by College Board. All rights reserved. Visit apcentral.collegeboard.com (for AP professionals) and www.collegeboard.com/apstudents (for AP students and parents). 8 AP® BIOLOGY 2005 SCORING GUIDELINES Question 4 (continued) Responds to a later exposure to the same infectious agent (secondary immune response) (4 points maximum) • • • • • • • • • Mediated by memory cells (T and/or B). Memory cells are specific for the same antigen encountered previously. Memory cells receptors/antibodies have greater affinity for the antigen. Production of antibodies/response is faster and/or to a greater extent. Origin of memory cells: i. Helper T cell → Memory Helper T → Memory B and T cells ii. Activated B cell → Memory B cell iii. Activated Cytotoxic T cell → Memory T cell Role of major histocompatibility complex (MHC), cytokines, IL-1, or IL-2 as related to secondary immune response. Memory cells are more numerous (or antibody concentration is higher). Memory cells are long-lived. Elaboration of why measles, mumps, chicken pox do not recur (vaccines), or common cold/flu do recur. Distinguishes self from nonself (4 points maximum) • • • • • • All cells have unique ID tags (flags, markers, proteins, glycoproteins, MHC, etc.). Origin of “self” markers of MHC by multiple alleles (polymorphic antigen receptors). Developmental selection in bone marrow and/or thymus where antigen receptors are tested (selfantigen receptors are eliminated, or inactivated/clonal selection). Mechanism of recognition (binding elicits immune response). Illustrate self/nonself incompatibilities: (e.g., autoimmune disease such as MS, transplant incompatibility; blood types, and pathogens mimicking MHC molecules, or cloaking with host cell membrane). Elaboration of: i. MHC (or human leukocyte antigens) ii. Distinguish between MHC I and II (e.g., MHC I—all nucleated cells; MHC II—dendritic cells, macrophages, B cells). Copyright © 2005 by College Board. All rights reserved. Visit apcentral.collegeboard.com (for AP professionals) and www.collegeboard.com/apstudents (for AP students and parents). 9 ...
View Full Document

This note was uploaded on 11/23/2009 for the course BIOLOGY 1101 taught by Professor Keith during the Winter '05 term at The University of Oklahoma.

Ask a homework question - tutors are online