Essay prompt Week #1

1. Essay prompt Week #1 Discuss the web of life in a biological community. Your essay should focus on energy flow, conversion, and loss in food chains, including the concepts of trophic levels and pyramids.

2. Key for Essay #1 Structural hierarchy Define community Producer’s-consumers; provide examples 10% loss at every level; explain why Energy is lost in a system Explain plant photosynthesis Need to eat at the carnivore level and cellular respiration Explain detritovore Define food chain and food web; provide sample diagrams Discuss/diagram energy pyramid, biomass pyramid; biomagnification pyramid Bonus: discuss exceptions inverted pyramid

3. Essay #2 AP BIO QUESTION 1996 The unique properties (characteristics) of water make life possible on Earth. Select three properties of water and • for each property, identify and define the property and explain it in terms of the physical/chemical nature of water. • for each property, describe one example of how the property affects the functioning of living organisms.

4. Note: you will need to print this slide out to see the words better. Key for Essay #2 -Prop. of water

5. ESSAY #3 AP BIO QUESTION 1991: Carbon is a very important element in living systems.a. Describe the various characteristics of the carbon atom that makes possible the building of a variety of biological molecules. b. Explain how reactions involving carbon-containing compounds can contribute to the greenhouse effect. c. The following structures are examples of two different categories of biological compounds. Describe how each category of compounds is important to the structure and function of living systems.

6. KEY TO ESSAY #3

7. STANDARDS: A. CHARACTERISTICS OF CARBON ATOMS: (Max of 4 points) __Ready availability, abundance __Atom small in size, outer (valence) electrons close to nucleus, so forms stable (strong) bonds __4 electrons in a valence-capacity of 8, forms 4 bonds to 4 other atoms __Forms covalent bonds __Can bond to other carbon atoms, no upper limit to size of carbon compounds __Bond angles form tetrahedron, resulting in 3-D structures, chains, rings, not just planar __Can form multiple C-C, C=C, C=C bonds __Can form isomers, different structures - same number and kind of atoms __Functional groups/combine with a variety of other elements __BONUS POINT: if get 3 above - Uniqueness, only Carbon has all of these characteristics

8. B. REACTIONS CONTRIBUTING TO GREENHOUSE EFFEC (Max of 4 points) __Overview: Increase in gas concentration (CO2, CO, CFC) causes greenhouse effect __CO & CO2 from respiration and combustion, or volatilization of limestone __CH4 from correct source - livestock, microbes, landfills, swamps, oil wells, etc. __CFCs from industrial activities, refrigerants, plastic foam, etc. PHYSICAL MECHANISMS OF HEATING: __Ozone destruction / more energy (UV) gets in __Trapping of Energy - "Blanket" traps heat or Reflection of Sun's Energy (technically incorrectbut common use in texts) __Good technical description of absorption, reradiation and wavelength shift leading to production or long wave infrared absorbed by greenhouse gases __Concept of sinks: CO2 removal by photosynthesis, CaCO3 formation, soluble in oceans, etc. CO2 addition by forest destruction, industry, etc.

9. C. BIOLOGICAL MOLECULES:(Max of 5 points) (Cannot get 10 points for this question without mentioning both category I and II) CATEGORY I: __Identification of molecule / category: Phospholipid, phosphoglyceride, fat, lipid, phosphatidylethanolamine / polypeptide. __Characteristics of molecule: Hydrophobic/hydrophilic, polar/nonpolar, amphipathic, or non-water soluble, high E bonds, sat/unsat C-C bonds. __Structural uses of molecule: membrane, lipid bilayer, fluid mosaic. __Functions of molecule (for example): (2 Max) Phospholipids: Regulation of membrane permeability, fluidity Fats: Structural, insulation, energy storage, water-proofing Steroids/Sterols: Hormonal, membrane fluidity Cholesterol: Animal membranes Fat soluble Vitamins: Coenzymes Prostaglandins: Neural modulators Waxes: Water-proofing

10. CATEGORY II: __Identification of molecule / category: Amino acid / protein / cysteine __Recognizing cysteine's role in disulfide bond formation __Characteristics of molecule: Side chains variable Peptide bonds may be formed Subunit (monomer, building block) of protein Levels of protein structure / zwitterion / as buffers __Structural roles: Keratin, collagen, cytoskeletal (tubulin, actin), etc. __Functional roles: Enzymatic - speed reactions (2 Max) (pepsin, glucose oxidase, etc.) Transport (Hb, Myb, permeases, HDL/LDL) Regulatory (oligopeptides, ex. hypothalamic releasing factors, insulin, glucagon, etc.) Contractile - actin, myosin Protection - antibodies

11. ESSAY QUESTION #4 • CELL QUESTION 1992: • A laboratory assistant prepared solutions of 0.8 M, 0.6 M, 0.4 M, and 0.2 M sucrose, but forgot to label them. After realizing the error, the assistant randomly labeled the flasks containing these four unknown solutions as flask A, flask B, flask C, and flask D. • Design an experiment, based on the principles of diffusion and osmosis, that the assistant could use to determine which of the flasks contains each of the four unknown solutions. Include in your answer • a description of how you would set up and perform the experiment; • the results you would expect from your experiment; and • an explanation of those results based on the principles involved. • (Be sure to clearly state the principles addressed in your discussion.)

12. Key to Essay #4 • EXPERIMENTAL SET-UP (1 point each) • ___ 1. Experiment based on concentration gradient • ___ 2. Experiment based on semipermeable membrane (dialysis tubing, thistle • tubes, plant or animal cells) • ___ *3. Experimental set-up (design) adequate to produce measurable results • ___ *4. (2 max) Experimental variables are eliminated (mass, volume, time, • temperature, tissue type, etc.) • ___ *5. Experimental set-up is exemplary (must include semipermeable • membrane) • B. RESULTS ( 1 point each) • ___ *1. Describes a measurable change • ___ *2. Correctly correlates the observed changes with molarities of unknowns • C. APPLICATION OF PRINCIPLES TO RESULTS (1 point each) • ___ *1. Correctly applies principles of diffusion and osmosis in the interpretation • of results (a correct analysis) • ___ 2. Demonstrates an understanding of the concept of water potential • (hydrostatic/turgor pressure) in analysis of results

13. Key to Essay #4 continued D. PRINCIPLES (1 point each) ___ 1. Demonstrates an understanding, or gives a correct definition of diffusion ___ 2. Demonstrates an understanding, or gives a correct definition of osmosis ** (must include both water and semipermeable membrane) ___ 3. Demonstrates an understanding, or gives a correct definition of selective permeability ___ 4. Describes how solute size and/or molar concentration (hypertonic/hypotonic) affects the process of diffusion through a membrane _______________________ Max possible = 14 * No points if the lab will not work. **Osmosis: the diffusion of water through a selectively (semi)permeable membrane in the following directions: -from higher water potential toward lower water potential -from hypotonic (hypoosmotic) solution toward hypertonic (hyperosmotic) solution -from higher water concentration toward lower water concentration -from lower solute concentration toward higher solute concentration -from region of lower osmotic pressure toward regions of higher osmotic pressure -from region of higher osmotic potential toward region of lower osmotic potential

14. ESSAY #5 Enzyme question • QUESTION I-2000 • 1. The effects of pH and temperature were studied for an enzyme-catalyzed reaction. The following results were obtained. • a) How do (1) temperature and (2) pH affect the activity of this enzyme? In your answer, include a discussion of the relationship between the structure and the function of this enzyme, as well as a discussion of how structure and function of enzymes are affected by temperature and pH.b) Describe a controlled experiment that could have produced the data shown for either temperature or pH. Be sure to state the hypothesis that was tested here.