Biology Forum Molecular Biology Are these right?–won’t take long..

last updated by MrMistery 17 years ago
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    • #8493
      biology_06er
      Participant

      Had an exam yesterday and would just like to know if I am right in a few MCQs…I have just written out the ones I chose:

      affinity chromatography is a purification technique that:
      separates proteins according to size
      explots an unique property of a protein
      separates proteins according to their hydrophilicity
      involves ion-exchange chromatography
      results in protein samples that are denatured

      cellulose acetate electrophoresis indicates that albumin:
      is -vely charged
      is +vely charged
      is a minor component of serum
      is a basic protein
      has a PI close to the ph of the electrophoresis buffer

      the rate of enzyme catalyzed rxns is usually determined by measuring the initial rate of rxns because:
      only the initial rate is simply related to the initial substrate concentration
      enzyme rxns are always fast
      at equlibrium the absorption of light will continue to increase
      otherwise the light absorption will go off the scale
      the initial rate is always the slowest

      Papain incubated with EDTA:
      Activates enzyme activity by binding divalent metal cationshave no effect on enzyme activty
      activate enzyme activty by modifying the casein substrate
      inhibit enzyme activty by binding divalent metal cations
      inhibit enzyme activty by binding divalent metal cations

      When acid is added to the rxn: ethanol + Nad+ <–> acetaldehyde + NADH + H+ the following is expected to happen:
      Increases the conc. of NADH

      interaction between cibacron blue and albumin is considered:
      Hydrophobic

      when the liver enzyme alcohol dehydrogenase oxidizes ethanol an increase in the absorbance of the solution occurs at 340nm. This is because:
      NADH is produced during the rxn

      In the lab where the enzyme papain is investigated, it was preincubated prior to assay to:
      ensure that the reactive site cysteine was in the reduced form

      I know there is heaps of q’s but any1 that can tell me if they are wrong/right will be great…I just wanna make sure I have got the marks for these so having the ans. to this post will be MOST appreciated!!

      Thanks you to whoever answers!!
      b_06er

    • #77415
      MichaelXY
      Participant

      You have a good memory, I can never remember questions in that detail after a test.

    • #77419
      biology_06er
      Participant

      haha i wish i had a good memory then I would do better on exams!…we actually get to take the paper home 😛

    • #77422
      MrMistery
      Participant
      quote biology_06er:

      Had an exam yesterday and would just like to know if I am right in a few MCQs…I have just written out the ones I chose:

      affinity chromatography is a purification technique that:
      separates proteins according to size
      explots an unique property of a protein
      separates proteins according to their hydrophilicity
      involves ion-exchange chromatography
      results in protein samples that are denatured

      The correct answer is "explots an unique property of a protein". The technique used to separate according to size is gel filtration chromatography.

      quote :

      apain incubated with EDTA:
      Activates enzyme activity by binding divalent metal cationshave no effect on enzyme activty
      activate enzyme activty by modifying the casein substrate
      inhibit enzyme activty by binding divalent metal cations
      inhibit enzyme activty by binding divalent metal cations

      EDTA binds metal ions through amine and carboxyl groups. However, i don’t think papain has metal prosthetic groups. You can look that up and you will have your answer.

      quote :

      When acid is added to the rxn: ethanol + Nad+ <--> acetaldehyde + NADH + H+ the following is expected to happen:
      Increases the conc. of NADH

      My guess is it would increase the rate of the backwards reaction, as the added H+ will increase the concentration of products.

      Don’t know the answers to the others, or i consider your answers correct.

      Cheers.

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