Transcript Key concepts for Essay #1

How to grade essays
 Use a highlighter to mark all the statements that are in
your essay that are on the rubric (give yourself points
according to the guidelines of the rubric)
 Use a red pen to write in the concepts you missed in
the section of the essay where that concept should
have been covered.
 At the top of the page, put the score you received and
circle it in pen.
 Voila! Done!
Essay Prompt #1
AP 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.
Key for Essay #1 -Prop. of water
Note: you will need to
print this slide out to see
the words better.
Essay Prompt #2
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 #2
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:
__Characteristics of molecule:
__Structural uses of molecule:
__Functions of molecule (for example):
(2 Max) Phospholipids:
Fats:
Steroids/Sterols:
Cholesterol:
Fat soluble Vitamins:
Prostaglandins:
Waxes:
Phospholipid, phosphoglyceride, fat, lipid,
phosphatidylethanolamine / polypeptide.
Hydrophobic/hydrophilic, polar/nonpolar,
amphipathic, or non-water soluble, high E
bonds, sat/unsat C-C bonds.
membrane, lipid bilayer, fluid mosaic.
Regulation of membrane permeability, fluidity
Structural, insulation, energy storage, water-proofing
Hormonal, membrane fluidity
Animal membranes
Coenzymes
Neural modulators
Water-proofing
CATEGORY II:
__Identification of molecule / category:
__Recognizing cysteine's role in
disulfide bond formation
__Characteristics of molecule:
__Structural roles:
__Functional roles:
(2 Max)
Amino acid / protein / cysteine
Side chains variable
Peptide bonds may be formed
Subunit (monomer, building block) of
protein
Levels of protein structure / zwitterion / as
buffers
Keratin, collagen, cytoskeletal (tubulin,
actin), etc.
Enzymatic - speed reactions
(pepsin, glucose oxidase, etc.)
Transport (Hb, Myb, permeases, HDL/LDL)
Regulatory (oligopeptides, ex.
hypothalamic releasing
factors, insulin, glucagon, etc.)
Contractile - actin, myosin
Protection - antibodies