Test 4 3 February 2017, questions PDF

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2BB3_2016_Test_4_Ver11.docx! Biochemistry!2BB3!!!!!!!!!!!!!!Test!4!!!!!!!!!!!!!!February!3rd,!2017! ! Note:!Please!check!your!examination!booklet!to!ensure!all!pages!are!there.!There!are!10!questions.!Please!mark!your!answers! clearly!on!the!examination!answer!sheet.!You!can!keep!the!examination!booklet.!There!are!several!different!versions!of!this! test,!therefore!it's!important!that!you!mark!your!version!on!the!CLASSROOM!ANSWER!SHEET!(scantron)!according!to! question!1!&!2.!

1.

Please mark question

1

c

2.

Please mark question

2

a

3. Hemoglobin is 50% saturated with oxygen when pO2 = 15 torr. If hemoglobin exhibited hyperbolic binding (as myoglobin does) with 50% saturation at 15 torr. Which of the following statements is correct? (pO2 =100 in the lungs and pO2 = 30 in the tissues; fractional saturation YO2 = pO2 / {K + pO2} and K=p50=pO2 when YO2=0.5) a) Hemoglobin can only use approximately 1/4 of its capacity to deliver O2 to the tissues b) The fractional saturation when pO2 = 30 torr is 0.24 c) Hemoglobin can only use approximately 1/3 of its capacity to deliver O2 to the tissues d) Hemoglobin can only use approximately 1/5 of its capacity to deliver O2 to the tissues e) The fractional saturation when pO2 = 100 torr is 0.59

a) b) c) d) e)

4. The helical structure of collagen contains _____. three right-handed helices wound around each other in a right-handed triple helix three left-handed helices wound around each other in a right-handed triple helix three left-handed helices wound around each other in a left-handed triple helix three right-handed helices wound around each other in a left-handed triple helix none of the rest

a) b) c) d) e)

5. Which amino acid is critical for crosslinking of collagen trimers? Cys Lys His Ser Gln

6. During the formation of microfilaments, which of the following occurs? a) none of the rest b) F-actin polymerizes, becoming G-actin c) ATP binds to F-actin d) polymerization proceeds quickly at first, then slows after about ten actin monomers have polymerized e) ATP hydrolysis is catalyzed by F-actin 7. Which of the following details the nucleotide-binding site when tubulin dimers assemble into microtubules? a) both alpha and beta sites are bound to GTP b) both alpha and beta sites are bound to GDP c) the alpha site is bound to GTP; the beta site is unoccupied following GTP hydrolysis and release of GDP d) the alpha site is bound to GDP; the beta site is bound to GTP e) the alpha site is bound to GTP; the beta site is bound to GDP

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2BB3_2016_Test_4_Ver11.docx! 8. What is the most prevalent secondary structure observed in the proteins of intermediate filaments? a) beta-sheets b) alpha-sheets c) alpha-helices d) both alpha-helices and beta-helices are observed e) beta-helices

a) b) c) d) e)

9. Bone and tendons contain _____ while hair and nails contain _____. collagen; keratin tubulin; keratin actin; keratin collagen; actin tubulin; collagen

10. When a cell moves along a surface, actin _____ occurs at the leading edge while _____ occurs at the trailing edge a) polymerization; depolymerization b) denaturation; renaturation c) none of the rest d) depolymerization; polymerization e) renaturation; denaturation THE END of QUESTIONS !

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