Final Exam Form 0 Spring 2002

Final Exam Form 0 Spring 2002 - Bil 255 Spring 2002 Form 0...

Info icon This preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Bil 255 Form 0 Final Exam - 5/2/2002 Spring 2002 Professors Glaser & Mallery Instructions: Pick the BEST choice from among those given. PART 1 . New material since Test #2 - 40 questions : 30 by Professor Glaser & 10 by Mallery GLASER New Material (30 questions): 01. When glucagon is added to hepatocytes (liver cells) the level of cAMP in these cells is elevated and glucose is released by the cells. Caffeine is an inhibitor of cAMP phosphodiesterase. Do you expect (think carefully)? a) Caffeine to potentiate the action of glucagon, i.e., small amounts of glucagon become more effective b) Caffeine to inhibit the action of glucagon c) Cannot answer based on these facts 02. Cholera toxin is an enzyme that modifies some G proteins so that their GTPase activity is abolished. When you add cholera toxin to hepatocytes in tissue cultures in the presence of epinephrine (adrenaline) cAMP levels rise in these cells, and remain high even after adrenaline is removed. In this absence of cholera toxin, removal of adrenaline results in an immediate drop in cAMP. If you could examine in these cells the state of the α , β , γ subunits of G protein, would you expect? a) To find most of the G proteins as α , β , γ complex b) Most of the G protein as α subunit separate from β , γ complex 03. The binding of ACTH to its receptor in the adrenal cortex results in a large increase in intracellular cAMP. Each ACTH molecule generates many cAMP molecules because (think very carefully)? a) Each receptor can activate many G proteins b) Each G protein can activate many adenyl cyclase molecules c) Adenyl cyclase has high catalytic activity d) a and c apply e) b and c apply 04. Enzymes can act as on/off switches because? 05. Upon addition of epidermal growth factor (EGF) to cells, the EGF receptor is phosphorylated at multiple sites on tyrosine residues. This phosphorylation? 06. The best description of a cell cycle is ?
Image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern