Bio Final 03

Bio Final 03 - Biology 131 Final Examination May 10, 2003...

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Unformatted text preview: Biology 131 Final Examination May 10, 2003 This examination is in two parts. First is a multiple-choice part, and your answers will be put on the attached Scantron sheet. Be sure to put your name and student number on the sheet. The second part of the exam consists of quantitative problems and short essays to be answered in the space provided. Be sure to put your name and student number on all of those pages. When you are finished, turn in the Scantron sheet and pages with the written answers: you should keep the multiple-choice questions. J = DAG/Ax; J = PAC RT x, =_1 —_ Vt FZ “x, Vr .__ 25””; mil/1 = 53mV10g£L ,for a monovalent cation, X. For a diavalent ion, the above equations must be divided by 2 (z=2), thus Vc, = 29 mV log (Can/Ca.) For a monovalent anion such as (31', z = -1, so Va = '58 mV log l V = V. - V. NI F = 10" coulomb's/mole (RT/F) = 23 mV A‘P=‘Pl_q’2- W=P*n Aq’:(R_RI)_(nI—HD) where C,- refers to the concentration of the j different solutes in the solution. Joules I'I=RTZC,=2.4-103 2C, mole L = .IGD, “[419, “[20, in 3, 2 and 1 dimensions, respectively. Thus, t increases with L2 (e.g., in 1 dimension, t = L2/2D). Constants, Algebraic Relationships, and Conversion Factors log 10 = 1; log 2 z 0.3; log 3 z 0.5; log 5 z 0.7; log 100 = 2; log 1000=3, etc. log (N3) = -Iog(B/A) = log A — log B log (A-B) = log A + log B; thus log 50 = log 10 + log 5 = i + 0.7 = 1.7 Avogadro number = 6x1023 lum = 10'3 mm = 10'4 cm 1L= 103 mL =103 ch=10'3m3 As prefixes to units, m = 103. u = 106,11 = 10"), K = 103 Speed of light in vacuum, c = 3 x 103 ms; energy of a quantum, E = hell, h = 6.6 10'“ joules’s 5.7.003 F / The pressure generated by the meniscus of water: P = {ET/re, where T is the surface tension of water (7 x 10'8 MPa-m=70 x 10'J N/m) and rc is the radius of curvature of the meniscus. 1 Pa = l joule/ng’; 1 atm = 0.1 MPa = 760 n11an :- 10 m H30 FHOSPLULL: '0' {"0— CM 43% es‘i'w w] -oH W. 0 H j Glycme _H ".n - i (GI) V Cvsfeme —CH,—-5H ‘" "b i (Cys) 5“ ; Alanine .. C. * ~@ - “as E neeigionine _CHI_CH2_S_CHJ "‘ i Valine ' [SH/CHJ ' _< m i (Val) \CHJ _' V ' ' . . fax -.- As we acid /0 —- I 9g: is D Lleucine _CH:_CH<CH’ ! c :1) CH: Giutamic acid 5: (Glu) E lsoleucine fiCH/CHI CH1 (tie) \CH: Asparagine 1 (A5“) Phenylalanine (Phe) /CH=CH u-CH —c "CH Glutarmne F : a“CH—CH? (Gm) ' —CH3_.CH’_ o=c< Tyrosine I Praline (fH-g—CH, (Tm _-Cl'{:_C/CH=CH\C CH CH / = I “CH,‘—‘C=CH Tryptophan '— a‘fi‘fi i? Hislidine ,LH ,1; (Trp) c\H/c\ /CH (His) \C/{i W NH CH/ ii H _ Lysine + _CHI_OH Hg _0 -—CH,—CH,-—-—CH,-CH,—NH, ,a s i! K Arinine Threonine __CH/CH=I T} (Ara) (Tm) \OH -« b I; —CH,—CH,—CH,—NH,-—C 'T' :5 R \ «5150? FA Part 1. Answer the following 30 questions on the Scantron sheet. All questions are worth 2.5 points, for a total value of 75 points. Note that the questions are not of equal difficulty, so make sure you budget your time so that you get to all of the easy ones. There is only one correct answer per question; in some cases, you may have to choose the best answer. 1. Some cells have Cay-based action potentials; that is, the depolarization depends on the opening of voltage-gated Caz“ channels. If the concentration of C325 outside the cell is 1 mM and the cytoplasmic concentration is the usual 100 nM, what is the maximum value that the action potential could reach? a. + 58 mV @- +116 mV c. 0 mV d. - 58 mV 6 -116 mV 2. The underlying basis of hydrogen bonding is a. the ability of carbon to form four covalent bonds with hydrogen b. the tendency of an amine group to pick up a proton and become positively charged . . 7 ‘ (6) the unequal sharing of electrons by the strongly electronegative atoms 0 and N when they form covalent bonds, thus creating charge separation ' d. the ability of an amino group to form a peptide bond with a carboxyl group with the loss of a water molecule ' ' - e. the tendency of a carboxyl group to lose a proton and become negatively charged, even at pH 5 3. Suppose that the cytoplasm of 'a cell consists of 100 mM K+, 100 mM of organic anions, and 100 mM glucose. The bathing medium has only 175 mM NaCl. Assuming that there is initially no hydrostatic pressure difference, which way will water flow? @1 out ofthe cell b. into the cell c. into the cell only if there is a negative membrane potential d. out of the cell only if there is a negative membrane potential e. depends on the equilibrium potential for potassium. 02003 F3 4. The molecule phosphatidyl choline 3. consists of a glycerol backbone with choline attached to all three carbons of the glycerol b. consists of 21 glycerol backbone with a fatty acid esterified to one glycerol carbon, the choline esterified to one glycerol carbon and a phosphate group esterified to the third carbon c. is a neurotransmitter related to acetylcholine, but used only in the parasympathetic branch of the autonomic nervous system d. is a component ofalpha helical proteins Cc) consists of a glycerol backbone with a fatty acid esterified to each of two of the glycerol carbons and choline connected to the third glycerol carbon via a phosphate ester 5. An action potential will be generated in a motor neuron if a. an 'excitatory input arrives at a dendrite ' b. an inhibitory input arrives at a dendrite 65 the spike generating region (the axon hillock) is depolarized to threshold d. acetylcholine is released from the neuron’s terminal e. the postsynaptic muscle fires an action potential 6. Which is the correct sequence of events in the fertilization of the sea urchin egg? acrosome reaction, sperm-egg fusiori, depolarization, Ca2+release, cortical reaction _ ' " . b. Ca2+ release, acrosome reaction, depolarization, sperm-egg fusion, cortical reaction c. Sperm-egg fusion, acrosome reaction, depolarization, cortical reaction, Ca2+ release ' ' d. Acrosome reaction, sperm-egg fusion, cortical reaction, Ca2+ release, depolarization e. Acrosorne reaction, Ca2+ release, sperm-egg fusion, depolarization, cortical reaction ' 7. When blood is ejected from the right ventricle, where does it go? a. to the right atrium to the pulmonary circulation c. to the systemic circulation d. to the blood vessels supplying the heart muscle itself 6. to the brain 8. The effect of the neurotransmitter, acetylcholine, on a postsynaptic cell is a .the opening of a ligand-gated ion channel that is permeable to both K" and Na)“ b. the opening of a Ca2+ channel c. the release of Caz’ from internal stores d. the activation of a G—protein via a seven—pass transmembrane receptor etemiined by the type of receptor, nicotinic or muscarinic, contained in the postsynaptic membrane 52603 F ‘/ 9. [n frog egg development, the site of sperm entry at. identifies the animal pole b. determines the future dorsal side @ determines the future ventral side d. occurs at the future site of gastrulation e. bears no relationship to the future dorsal-ventral axis A. Water efflux from the guard cell . Opening of Ca'+ channels and increase in intracellular Ca2+ B. Activation of receptor by ABA t . Membrane depolarization (VI11 becomes more ositive) ' C. Opening of Cl' channels and Cl' efflux I. Membrane hyperpolarization (Vm D. Activation of H+-ATPase I J. Secondary transport of Cl" into guard ' cell E. Water influx into the bard cell. K. K‘“ efflux F. Activation of blue Iiht recetor L. K+ influx 10. Above are listed a series of events that relate to guard cell operation. Which of the following sequence of events correctly describes guard cell opening? Don’t make this too hard—only one sequence makes any sense. " a. B, G, C, H, K, A 11. Repeat question 10 for guard cell closing. 12. Suppose that the meniscus of water in a xylem tube has a radius of curvature of 10 pm. How far up the xylem tube, in meters, can water move by capillarity? Everything you need to solve this problem can be found on the first two pages. a. 140 um b.l.4mm ; _ ‘ ’ i "-‘- : _IL{I)0-3r‘?q c.140mm * d 1.4m ‘ .,oi~ml’a e. 14m .145“ 19"“ 5 92008 F 5' 13. What one condition must be satisfied in order for water to move into a root hair cell From the soil? :1. the osmolarity must be greater in the cell than in the soil b. the osmolarity must be greater in the soil than in the cell c. the hydrostatic pressure must be greater in the cell than in the soil (1. the water potential must be greater in the cell than in the soil (Bathe water potential must be greater in soil than in the cell 14. When a coleoptile responds to unilateral blue light auxin is transported away from the light and the coleoptile bends toward the light b. auxin is transported toward the light and the coleoptile bends toward the light 0. auxin is transported toward the light and the coleoptile bends away from the light d. auxin is tranSported away from the light and the coleoptile bends away from the light e. the turning is mediated by phytochrome and auxin 15. What fundamental process leads to the production of the flowing plant’s microspore and how many function microspores are produced from a single microspore mother cell (microsporocyte)? a. mitosis, 4 b. mitosis, 2 meiosis, 4 . meiosis, l . e. mitosis, 1 '16. By what mechanism do root hairs take up NO3' from the soil? a. osmosis b. through ion channels specific for NO; c. by a primary pump powered by ATP y secondary transport with the inward movement of H+ providing the energy - e by secondary transport with the inward movement of Na+ providing the energy 17. The visible (to humans) part of the electromagnetic spectrum consists of what wavelengths? a. 400-700 mm b. 100-1000 um 400-700 nm (1. 400-700 um e. 100-1000 nm 03MB: 1:? 18. How do the cones that are responsible for color vision differ from each other? a. they use three different forms of retinal to detect red. green and blue b. they use three different neurotransmitters to communicate with the bipolar cells c. the three classes of cones each have a different color filter that allows only certain wavelengths to reach them (g; the three classes of cones each have different opsin proteins that determine what wavelengths of light the retinal is sensitive to e. they are located in distinct regions of the retinal, and the optics of the eye diffracts light of different wavelengths to the different regions 19. The arteries carry blood away from the heart. With one exception, arterial blood is fully oxygenated. What is the exception? ' a. the aorta b. the femoral artery c. the carotid artery d. the hepatic artery - the pulmonary artery 20'. The characteristic time for a particular molecule to diffuse 10 pm is 3 5. How long would it talge for the same molecule in the same medium to diffuse 1 mm? _ a. 3 x 10 s ' "‘ ' b.3x103s @3x1045' d3x1055 e.3x106s 21. When' the P co; of the arterial system exceeds 40 torr, the reSponse of the respiratory system ' a. is to decrease metabolism in order to reduce C02 production b. is to cause inspired air to be enhanced in 02 I Q is to increase the rate of breathing d. is to acidify the blood so that more CD; can be carried as HCOg‘ e. is to decrease the rate of breathing 22. The rate of breathing in humans is controlled principally by @7 cells that monitor the Pcoz in the blood b. cells that monitor the P02 in the blood 0. cells that monitor the degree of saturation of hemoglobin d. cells that monitor the degree of stretch of the alveoli e. cells that monitor the level of ammonia in the blood X603 F 7 23. Elevated levels of cytoplasmic Ca2+ are involved in which of the following processes? a. secretion of amylase from aleurone cells b. cardiac muscle contraction c. skeletal muscle contraction d. sea urchin egg cortical vesicle secretion all of the above 24. The puffer fish toxin, tetrodotoxin (TTX), completely blocks voltage gated sodium channels. Suppose a vertebrate motor unit (motor neuron and associated muscle fiber) were bathed in TTX, blocking the transmission of an action potential in the neuron and the secretion of ACh. Would the muscle contract if ACh were added to the bath? a. yes, because the ACh receptor channel in the muscle would be opened b. no, because the TTX would prevent Ca2+entry into the muscle fiber from the bath 1 yes, because the muscle fiber would be depolarized to threshold d? no, because the TTX would block the sodium action potential in the muscle e. yes, because the TTX would have no effect on the muscle fiber itself 25. If one increases the solution pH from 7.0 to 10.0, the net charge on the free amino acid, lysine, will a. change from +1 to +2 behangefrom+2to+1 _ ,h H .10 figs , c. not change " H i first; @jchange'from +1 to-l . * V 1 _ h ‘4": ‘3 A _ . . '1 ' "I. ‘ ,_."|a‘ V , 3 e.changefrom0tol I _ .1. i “pg-Mi N eo s ‘.' "‘1: I 4‘1. 26. Suppose an action potential is started simultaneously at two different places on an axon. What happens to the action potentials as they meet? a. they sum to give an action potential of twice the amplitude 13. they cross without affecting each other i they annihilate each other because the sodium channels are inactivated (1. they annihilate each other because the intemal Ca2+ stores are exhausted e. they never meet because action potentials can only propagate in one direction 02643 F 9 27. Ouabain is a plant alkaloid that inhibits the Na-K ATPase. What would be the effect of applying ouabain to neuron? 3. action potentials would immediately cease as sodium and potassium channels would be blocked b. action potentials would be spontaneously initiated due to the depolarization of the membrane potential there would be no effect on action potentials until many had been fired e. there would be no effect on action potentials until many had been fired, c. action potentials would immediately cease as the sodium and potassium gradients would immediately collapse @- I because the amount ofcellular Na gained and K lost in each AP is small in chemical terms because the amount of cellular Na lost and K gained in each AP is small in chemical terms 28. When Nusslein-Volhard used a micropipette to remove cytoplasm from the anterior pole of the Drosophila egg, a two-tailed embryo resulted. What was the important substance that she removed? a. hunchback protein b. hunchback mRNA c. bicoid protein bicoid mRNA e. nanos'mRNA 29. What is a transcription factor? a protein that interacts with DNA and regulates transcription of a particular gene ‘0. mRNA that binds to DNA and regulates transcription of a gene 0. a small ion such as Ca2+ that regulates protein synthesis d. an external factor such as sperm that turns on the zygotic genome e. a change in membrane potential that activates a G-protein 30. Suppose that the synaptic input to a dendrite of a neuron opens channels that are specific for a certain ion. What determines if this input is excitatory or inhibitory? a. excitatory if it depolarizes the membrane, inhibitory if it hyperpolarizes the membrane b. inhibitory if it depolarizes the membrane, excitatory if it hyperpolarizes the membrane c. inhibitory if it increases Ca2+ , excitatory if it decreases Ca” @ inhibitory if the equilibrium potential for the ion is below threshold, excitatory if the equilibrium potential is above threshold e. excitatory if the equilibrium potential for the ion is below threshold, inhibitory if the equilibrium potential is above threshold. 0%” F ?‘ Abmrbanq- s—W Part 2 Name (Printed) I W Signature _________________________ Student Number -—-—-—._____.._________________ Enter your name and student number In the space above and also on the following pages. 1. (10) Shown below on the left are the absorbance spectra for the two forms ofthe phytochrorne molecule. The x~axis ofthis graph shows the fraction ofthe light that is absorbed by a suspension ofthe molecules as a function of the wavelength ofthe li Pro I His Ser (is His \ “I” Thioether 5p. linkage A. (2) Which absorbance spectrum, 1 or 2, is for P1}? 1 Which is for Pr? |' B. (2) In the representation ofP,, circle the part ofthe molecule that absorbs light. Circle the protein part of the Pl}, C. (6) Suppose that lettuce seeds that have been stored in the dark are exposed to a pulse of light of wavelength 730 nm. What form will phytochrome be in, Pr or Prr? Pr . Will the seeds germinate? (un- SuppOSe the same seeds are then exposed to a pulse of 670 nm light. What form will phytochrome be in? Py— Will the seeds germinate? 1 g Suppose the same seeds are then exposed to sunlight. What form will phytochrome be in? Fr 7‘: Per Will the seeds germinate? K 10 0266.13 FM Name (Printed) ————-———___.____________________ 2. ( 15) On the diagram below of the vertebrate photoreceptor rod outer segment, show the [Nation of the key components of the phototransduction process. Then describe the events that lead from the absorption of a photon by the photoreceptor molecule to the electrical response of the photoreceptor cell. Be sure to mention the nature of the electrical response. we,“ min-mt M q L41“ Us W1— ltvh ’H—t flags 4.: -."l’rmJ Lox-323M“, file's-11M “- mmw“ LW “1 110 51-43% - I m “we” “K “‘ QM W idwcl" maul mark GTP- M/tlrivwli‘cg ‘+ m Na CW K “1 £09“sz \K “We Wm 09_ IeG'mPJ '5‘ fibhy". 4 ll Name (Printed) 3. (10) The graph below shows the hemoglobin-O; binding curve in the capillaries ofthe lung 5. Draw the curve that could represent the binding of O; to hemoglobin in the tissue capillaries. Mention three factors that are different in the tissue capillaries that would cause the curve to shift in the direction you have indicated. Do Not Write Below This Line 92003 Fm Name (Printed) 4. (10) Shown below is an On-Center receptive field. Identify the four cell types that are shown and in the blanks, write the letters that indicate the response of the cells to light in the two regions. téjloti m,1 A WE RCJFM."°"; Vm +:; thm; ofi | _1_ ._.__.C MD WE NF 13 611610 F /.3 Name (Printed) M 5.(15) A. ( 10) Show the formation of a peptide bond between serine and aspartic acid. That is, write a balanced chemical equation in the form A + B —> C + D, where A and B are serine and aspartic acid (NOT necessarily in that order). Choose A and B so that sen'ne is the C -terminal amino acid and aspartic acid is the N—terminal amino acid of the dipeptide. H Horse 1 II I 1 {/0 H {0 I n '- "1 'C c/ro *‘ H3~__L_c’ a Cr c\0~ H -. — In. I \ - H 3N 1 \0 CF“. 0 fflz [C L CH ' 0H 1 1 r arrive 04C“, OCCQO J” B. (5) Assume that the dipeptide above is a segment of the cytoplasmic portion of L-type calcium channel in cardiac cells and is responsible for the response of the cells to beta- adrenergic stimulation by norepinephrine (NE). Show how the dipeptide Would be modified by NE stimulation. + I 1' ’ I [/0 Haw?“ “N‘s” eH-L CH1. i ,R o o ‘0 | Ho-¢ao '- 0 14 026'd3 /‘/ ...
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Bio Final 03 - Biology 131 Final Examination May 10, 2003...

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