BIO 212
Fall Semester 2016 Honor signature ______
First Test
Lab (circle one): Huber Monday Stanga Monday Huber Wednesday
Multiple Choice (2 pts each)
______1. Which of the following “themes in the study of life” is misstated?
a. Evolution – biology’s core theme – accounts for the unity and diversity of life.
b. Life requires the transfer and transformation of energy and matter.
c. Organisms interact with their environments, exchanging matter and energy.
d. New properties emerge at successive levels of biological hierarchy.
e. The processes of life are based on expressed and transmitted information in the form of protein.
______2. A species (like Symplocarpus foetidus ... the skunk cabbage) belongs to one taxon at each category of classification. Which of the following categories of classification to which Symplocarpus foetidus belongs would have the smallest number of other species? (That is, which of the following categories of classification has the least breadth?)
a. Class Monocots d. Order Alismatales
b. Family Araceae e. Kingdom Plantae
c. Phylum Anthophyta
______3. Which stable, subatomic particle is the most relevant to understanding the chemical reactions of molecules?
a. proton c. neutron
b. neutrino d. electron
______4. What is the valence of nitrogen (N)?
a. one d. four
b. two e. five
c. three
______5. When a tree’s transpiration stream is moving on a normal sunny day, which of the following locations has the lowest water potential?
a. air outside a leaf d. soil solution around the roots
b. air spaces within a leaf e. xylem vessel halfway up the tree
c. photosynthetic leaf cell cytoplasm
______6. Radioactive sulfur (35S) is used to track the synthesis and fate of amino acids that contain sulfur, such as methionine. These amino acids are found in proteins. DNA, RNA, starch, and glycogen are also biological macromolecules, but none of the individual constituent monomers contain sulfur. Radioactive sulfur-35 decays by β- emission. Identify “X” in the reaction shown.
a. sulfur c. chlorine
b. phosphorus d. carbon
______7. We placed the element sulfur (S), which is found in acetyl-CoA and the amino acid methionine in the _____ :
a. alkali metal and halogen group. d. “energy currency” group.
b. alkaline Earth metal group. e. trace element group.
c. covalent bond group.
______8. Which of the following is hypotonic to all of the others? (Assume salts dissociate 100%. Glucose is a sugar and doesn’t dissociate; the other three are salts.)
a. 2 M glucose (C6H12O6) solution c. 2 M CaCl2
b. 2 M NaCl solution d. 2 M KCl
______9. Which of the following molecules has the highest boiling point?
a. ethane (C2H6) d. methylamine (CH3NH2)
b. methane (CH4) e. methyl fluoride (CH3F)
c. methanol (CH3OH)
______10. Which combination of magnification and resolution allows one best to visualize a small cellular structure with maximum clarity?
a. 1,000-fold … 200 nm c. 1,000-fold … 0.2 nm
b. 1,000,000-fold … 200 nm d. 1,000,000-fold … 0.2 nm
______11. How could you make a living human’s red blood cell plasma membrane more fluid?
a. replace phospholipids containing 16:1D9 fatty acids with some cholesterol
b. replace some 18:0 fatty acids with 16:0 fatty acids
c. replace some 18:2D9, ∆12 fatty acids with 18:0 fatty acids
d. Two of the above would make a living human rbc’s plasma membrane more fluid.
______12. In the laboratory, as fluid moved up into a thistle (containing dilute solution that was getting even more dilute) from a beaker (with deionized water), which of the following was (or were) increasing in value in the thistle fluid?
a. osmotic potential c. pressure potential
b. gravitational potential d. Two or more of the above were increasing in value.
______13. Where would the attractive force between two ions of opposite charge be the weakest? (hint: The symbol κ stands for the dielectric constant in the equation to the right.)
a. dissolved in ethanol where the value of the dielectric constant is 24.3
b. dissolved in water where the value of the dielectric constant is 78.5
c. on the surface of a water-soluble, globular protein where the value of the dielectric constant is (about) 58.2
d. in the interior of a water-soluble, globular protein where the value of the dielectric constant is 4.5
______14. Large bodies of water often moderate (or buffer) changes in ambient air temperatures. What property of water is most directly responsible for this ability of water?
a. water’s density of 0.997 g/cm3 d. water’s heat of vaporization of 2.26 kJ/g
b. water’s dielectric constant of 78.54 e. water’s surface tension of 71.97 dyne/cm
c. water’s specific heat of 4.184J/g/ºC
______15. The resolution of a microscope is determined by (1) the wavelength of light or electrons used (l), (2) the refractive index (n) of the medium separating the specimen from the objective and condenser lenses, and (3) half the angular width (q) of the cone of rays collected by the objective lens from a typical point in the specimen. The equation describing this relationship is shown above. Which of the following best describes how resolution is related to the wavelength (λ)?
a. They are directly proportional.
b. They are exactly equal, except for units.
c. They are inversely proportional.
d. Their relationship would appear as a rectangular hyperbola when plotted.
______16. Which simple functional group acts as an organic base, and so is usually protonated (and has a +1 charge) at physiological pH values?
a. amino d. methyl
b. carboxyl e. sulfhydryl
c. hydroxyl
______17. How many chiral (asymmetric) carbons does the amino acid molecule drawn to the right have?
a. 0 d. 3
b. 1 e. 4
c. 2
______18. Reactions having which of the following values within a temperature range are always thermodynamically possible within that temperature range?
a. ΔH > 0 and ΔS > 0 c. ΔH < 0 and ΔS > 0
b. ΔH > 0 and ΔS < 0 d. ΔH < 0 and ΔS < 0
______19. The molecular weight of alanine is 89 g/mole. To make 500 mL of a 1.00 molal (m) solution of alanine you would:
a. add 89 g of glycine to exactly 500 g of water and then dissolve.
b. add 44.5 g of glycine to exactly 500 g of water and then dissolve.
c. add 89 g of glycine to 400 mL of water, dissolve, and bring the volume up to 500 mL.
d. add 44.5 g of glycine to 400 mL of water, dissolve, and bring the volume up to 500 mL.
______20. For coupled enzyme reactions, one:
a. multiplies equilibrium constants and multiplies DG values.
b. multiplies equilibrium constants and adds D G values.
c. adds equilibrium constants and multiplies DG values.
d. adds equilibrium constants and adds DG values.
______21. Which red blood cell metabolic pathway converts NADH back to NAD+ so that glycolysis can continue to produce ATP?
a. lactate fermentation c. phosphogluconate
b. methemoglobin reductase d. Rapoport-Leubering
______22. What type of microscope was used to get the view of the sideways stack (“rouleaux”) of red blood cells seen to the right?
a. compound light c. scanning electron
b. dissecting d. transmission electron
______23. The graph to the right is from the study of turnip peroxidase’s activity (i.e., reaction velocity) as influenced by a factor. The X-axis should be labeled ______.
a. Peroxidase amount added (mL)
b. Temperature (°C)
c. pH
d. H2O2 concentration (%)
e. Time (sec)
______24. Which of the following shows allosteric inhibition with the enzyme phosphofructokinase?
a. AMP d. NADH
b. ATP e. pyruvate
c. fructose-6-phosphate
______25. The pair of molecules to the right is an example of ______isomers?
a. cis-trans c. structural
b. enantiomeric d. They aren’t even isomers!
______26. When calmodulin binds Ca2+ ions, the calcium ions go from being in ion-dipole interactions with hydrating water molecules (where the dielectric constant is 78.5) to forming ionic bonds within the interior of the calmodulin (where the dielectric constant is about 4.5). These ionic bonds are ______than the old bonds, and this would ______heat.
a. stronger … require the input of c. weaker … require the input of
b. stronger … release d. weaker … release
______27. Which level of protein structure for a single polypeptide involves London forces, Debye interactions, and Keesom interactions of the amino acid residue R-groups?
a. primary c. secondary
b. quaternary d. tertiary
______28. The value(s) of which of the following is (or are) changed by the presence of an enzyme?
a. Eact (activation free energy) c. ΔG (change in free energy of the reaction)
b. Keq (equilibrium constant) d. Two or more of the above are affected.
______29. Which of the following mechanisms allows O2 gas to cross the plasma membrane of a red blood cell?
a. facilitated diffusion d. secondary active transport
b. osmosis e. simple diffusion
c. primary active transport
______30. The enzyme-substrate complex intermediate with the highest free energy is known as the ______.
a. activation free energy (EA) c. catalytic efficiency (kcat/KM)
b. active site d. transition state
Short answer and problems.
1. a. Draw the molecular structure of the dipeptide alanyl-tyrosine (alanine―tyrosine) as it would be found at pH = 7.0. (4 pts)
b. On your drawn structure, carefully circle and name four different simple functional groups. (4 pts)
c. On your drawn structure, draw an arrow to and name the single covalent bond that connects the two amino acid residues together. (1 pt)
d. Write the name of the complex functionality which that single covalent bond is part of in the blank to the lower right. (1 pt)
If you can’t remember how to make the connection or how to draw the entire amino acid, draw the parts (alanine and tyrosine) or just the R-groups for partial credit.
Functionality containing bond: ______
2. Mad cow disease is an example of a transmissible spongiform encephalopathy (TSE). Diseases like mad cow disease are transmissible because they are capable of being transferred from one animal to another, spongiform because they cause the appearance of sponge-like holes in the brain of those affected, and encephalopathic because they are neurodegenerative diseases of the brain. Unique, small proteins called prions are involved in the progression of the disease. A “normal” prion is shown to the left in the diagram, and a prion in a patient with TSE is shown to the right. Label as precisely as possible the three kinds of secondary structure found in these prions. (Hint: Multiple copies of the prions would have the same tertiary structures as the ones shown.) (3 pts)
3. List the four claims of the fluid mosaic model of the membrane. You do not need to explain them, but you do need to state them carefully and completely for full credit. (5 pts)
_____ 4. The molecule in the box to the right is ______. (2 pts)
a. cholesterol
b. a fatty acid
c. a glycerophospholipid
d. an oligopeptide
e. a triacylglycerol
5. Enzymes are important molecules in cells that catalyze reactions. Below is an energy diagram illustrating the difference in an enzyme-catalyzed reaction versus an uncatalyzed reaction. Using the list to the left, write in the correct letter for each empty box. Answers can only be used once, and some answers may not be needed. (0.5 pt each)
A. Activation free energy
B. Catalyzed reaction
C. Equilibrium constant
D. ΔG for reaction
E. ΔH for reaction
F. ΔS for reaction
G. Free energy
H. Products
I. Reaction progress
J. Reactants (Substrates)
K. Temperature
L. Transition state
M. Uncatalyzed reaction
6. We agreed in class that two of the most unusual properties of red blood cells membranes were their flexibility and their elasticity. We traced flexibility back to the relatively weak London forces between the fatty acid tails of the phosphoglycerolipids and cholesterol that make up the two leaflets of the plasma membrane. On the other hand, we traced the elasticity back to the cytoskeleton and its attachment sites to plasma membrane proteins. (Total possible value is 9.5 pts.)
Name (below) the major proteins found as part of the cytoskeleton and as part of the plasma membrane that are involved in this elasticity. (0.5 pt each)
Place an asterisk (*) beside each integral (or intrinsic) single pass or multiple pass membrane protein. (0.5 pt each)
Place a (#) beside the one protein most responsible for the elasticity. (1 pt)
Describe (below) how the elasticity works, what weak intermolecular forces are involved, and how the cytoskeleton allows a red blood cell to recover its biconcave shape after passing through a capillary. A labeled diagram may help you in this. (4.5 pts)
Cytoskeleton proteins Plasma membrane proteins
(found in the “rbc ghosts” “skeletons”) (found in the rbc “ghosts”, but not in the “skeletons”)
1. 1.
2. 2.
3. 3.
How the elasticity works, what intermolecular forces are involved, and how the cytoskeleton allows a red blood cell to recover its biconcave shape (perhaps with a labeled diagram):
7. A study was conducted to determine the thermodynamic parameters of substrate binding to horseradish peroxidase by using substrate analogues like benzohydroxamic acid (BHA), which binds to the active site of the enzyme using three hydrogen bonds (see dashed lines in the diagram below right), one each to the amino acids arginine (Arg38), histidine (His42), and proline (Pro139). The benzene ring portion of BHA forms London forces with hydrophobic amino acids in the active site (not shown). The reaction is given here (dotted line represents the three hydrogen bonds and the London forces):
Peroxidase + BHA ↔ Peroxidase∙∙∙BHA
Before binding, of course, the horseradish peroxidase and BHA are both in water and hydrated to whatever extent is possible. The values of ΔGº, ΔHº, and ΔSº for substrate binding were measured at 25º C (298 K) and are as follows: ΔGº = -13.5 kJ/mol, ΔHº = -39.8 kJ/mole, and ΔSº = -0.0883 kJ/mol•K.