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.

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

Key for Essay #1

Essay #2AP BIO QUESTION 1996

The unique properties (characteristics) of water make life possible on Earth. Select three properties of water and

a) for each property, identify and define the property and explain it in terms of the physical/chemical nature of water.

b) for each property, describe one example of how the property affects the functioning of living organisms.

Note: you will need to print this slide out to see the words better.

Key for Essay #2 -Prop. of water

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.

KEY TO ESSAY #3

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

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 incorrect but 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.

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, fluidityFats: Structural, insulation, energy storage, water-proofing

Steroids/Sterols: Hormonal, membrane fluidity Cholesterol: Animal membranes

Fat soluble Vitamins: CoenzymesProstaglandins: Neural modulatorsWaxes: Water-proofing

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 formedSubunit (monomer, building block) of

proteinLevels 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, myosinProtection - antibodies

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) a description of how you would set up and perform the

experiment; (b) the results you would expect from your experiment; and (c) an explanation of those results based on the principles

involved.

(Be sure to clearly state the principles addressed in your discussion.)

ESSAY QUESTION #4

A. 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

Key to Essay #4

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

Key to Essay #4 continued

ESSAY #5Enzyme 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.