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Biology Grade 11 Unit 3: Enzymes

national exam questions have come from this unit. It runs 34 pages; one careful study pass takes about 3.1 hours, and its difficulty is harder among Biology units. Each section below lists the questions set from it, with the year, and opens the page that teaches it.

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3.1 What are enzymes? · read p. 74
Not asked in a national paper yet.
3.2 Properties and functions of enzymes · read p. 76
Not asked in a national paper yet.
3.2.1 General properties of an enzyme · read p. 76
  • 2018 E.C., Q37 – What happens when an enzyme is exposed to extreme pH or temperature?
  • 2018 E.C., Q32 – Which of the following statements about enzyme specificity is true?
  • 2018 E.C., Q33 – What causes the denaturation of an enzyme?
  • 2018 E.C., Q36 – Which factor does NOT affect enzyme activity?
  • 2017 E.C., Q32 – If a given enzyme works only at temperature range of 20 and 45∘C and the potential of hydrogen ions that ranges from 4 to 9 . Which one of the following works best during the optimization of these two factors for the enz
  • 2016 E.C., Q71 – Which one of the following properties of enzymes shows their catalytic nature?
  • 2014 E.C., Q59 – Which of the following external factors influence the turnover rate of enzymes by completely damaging their tertiary structure?
  • 2013 E.C., Q53 – Which one of the following statements explains the specificity of enzymes? Enzymes
  • 2013 E.C., Q92 – Identify the statement that correctly explains the factors of an enzyme activity.
  • 2011 E.C., Q14 – Which one of the following conditions is least likely to denature an enzyme?
  • 2011 E.C., Q86 – If other conditions were to remain constant, which one of the following changes would explain a reduced rate of activity in an enzyme-controlled reaction? Increase in
  • 2009 E.C., Q30 – Among the following factors that affect enzyme activity, which one dose NOT cause enzyme denaturation?
  • 2009 E.C., Q65 – What happens when enzymes become denatured?
  • 2009 E.C., Q2 – Which of the following substance can be used over and over again in an enzyme catalyzed reaction?
  • 2008 E.C., Q85 – What causes tomato fruits to ripen much more slowly when kept in a refrigerator than if left on a table at room temperature?
  • 2007 E.C., Q69 – Which of the following properties of enzymes makes it possible that a single enzyme molecule can act on many substrate molecules?
  • 2006 E.C., Q3 – In the case of enzymatic chemical reactions, what do you call the substance that is acted up on by an enzyme?
3.2.2 The function of enzymes · read p. 79
  • 2013 E.C., Q80 – What happens when the substrate molecule binds to the active site or an enzyme?
3.3 Protein structures · read p. 82
  • 2017 E.C., Q21 – Four students draw four different big protein structure posters. The contents of each of their structure are displayed in the following table. Based on the above information, which student draw secondary and quaternary s
  • 2016 E.C., Q82 – Which one of the following statement is correct about the structural organization of hemoglobin? It is formed
  • 2011 E.C., Q2 – What is the shape of an enzyme molecule?
  • 2009 E.C., Q15 – Which level of protein structural organization involves two or more polypeptide?
  • 2008 E.C., Q31 – Which of the following is made of globular proteins?
  • 2007 E.C., Q48 – The most complex structure of proteins is called
  • 2007 E.C., Q26 – At which level of structural organization do proteins have the alpha helix shape?
3.4 Enzyme substrate models · read p. 82
Not asked in a national paper yet.
3.4.1 Enzyme-substrate binding models · read p. 82
Not asked in a national paper yet.
3.4.2 Enzymatic transition state · read p. 87
Not asked in a national paper yet.
3.5 Enzyme regulation · read p. 88
  • 2017 E.C., Q23 – What happens to the substrate molecule when competitive inhibitor binds with an enzyme? It
  • 2017 E.C., Q25 – What will happen to the reaction if you add a certain inhibitor or activator to the substrate having allosteric enzyme set up?
  • 2017 E.C., Q22 – How does the induced-fit model explain enzyme specificity? They
  • 2016 E.C., Q11 – Which one the following statements explains how the allosteric inhibitors act on enzymes activities? By
  • 2016 E.C., Q73 – In the lock-and-key model of enzymatic action, the activation energy is lowered through
  • 2015 E.C., Q68 – Which one of the following sentences explains the lock-and-key model of enzyme action? The
  • 2015 E.C., Q70 – How does a competitive inhibitor affect an enzyme catalyzed reaction? By
  • 2014 E.C., Q58 – How do enzymes bind and act on their substrates? By using the
  • 2013 E.C., Q95 – Cyclooxygenase-2 is an enzyme that catalyzes the conversion of arachidonic acid to prostaglandins, which promote pain and fever in our body. The pain killer ibuprofen, act as non-competitive inhibitor of cyclooxygenase-2
  • 2013 E.C., Q93 – Which one of the following is true about allosteric regulation?
  • 2011 E.C., Q66 – Which of the following can reverse or reduce an allosteric enzyme inhibition?
  • 2011 E.C., Q87 – Which of the following statements best describes an induced fit-model?
  • 2011 E.C., Q36 – Which model of enzyme action requires that the shape of the substrate molecule is complementary to that of the active site?
  • 2010 E.C., Q31 – Which kind of enzyme inhibitors bind to enzyme only weakly and the bond that hold them breaks easily releasing the inhibitor to allow the enzyme to become active again?
  • 2010 E.C., Q20 – In a metabolic pathway(A-->B-->C-->D) where each step is catalyzed by a separate enzyme which substance in the pathway serves as an allosteric regulator?
  • 2009 E.C., Q28 – Which class of enzyme inhibitors has similar shape as that of the normal substrate?
  • 2007 E.C., Q25 – Which of the following substance has a shape which is similar to that of the substrate of an enzyme?
  • 2005 E.C., Q72 – Which of the following types of enzyme inhibitions can be removed when the end product of the metabolic pathway is depleted?
3.6 Types of enzymes · read p. 91
Not asked in a national paper yet.
3.6.1 Enzyme structural classification · read p. 92
Not asked in a national paper yet.
3.6.2 Basic classification of enzymes · read p. 92
  • 2017 E.C., Q28 – Which one of the following classes of enzyme and type of reactions they catalyze is correctly matched?
  • 2014 E.C., Q45 – The following are reaction types catalyzed by different classes of enzymes: 1. Transfering hydrogen and oxygen atoms 2. Changing of the molecular form of the substrate 3. Joining of two molecules by the formation of new
  • 2009 E.C., Q50 – Which type of enzyme catalyzes the joining of two molecules by the formation of new bonds?
  • 2008 E.C., Q36 – Which class of enzymes joins to molecule together by formation of new bonds?
3.7 Factors affecting enzyme action · read p. 94
Not asked in a national paper yet.
3.7.1 Description on factors affecting enzymatic actions · read p. 95
Not asked in a national paper yet.
3.8 Enzyme kinetics · read p. 96
Not asked in a national paper yet.
3.9 Application of enzymes in industries and their benefits · read p. 98
Not asked in a national paper yet.
3.9.1 Uses of enzyme application · read p. 99
Not asked in a national paper yet.
3.10 Malting in Ethiopian tradition · read p. 100
Not asked in a national paper yet.
3.10.1 Steps of modern malting · read p. 101
Not asked in a national paper yet.
3.10.2 Why is malting for? · read p. 101
Not asked in a national paper yet.
3.10.3 Traditional malting for local alcohol production · read p. 102
Not asked in a national paper yet.
3.11 Renowned Biochemists in Ethiopia · read p. 103
  • 2018 E.C., Q38 – Which of the following is an example of a cofactor required by some enzymes for activity?
  • 2018 E.C., Q34 – Which of the following is a characteristic of an enzyme's active site?
  • 2018 E.C., Q31 – What is the primary role of enzymes in biochemical reactions?
  • 2017 E.C., Q19 – Which one of the following statements is correct about the catalytic activities of enzymes? They
  • 2015 E.C., Q72 – The following graph shows the rate of reaction of catalase enzyme at a constant temperature and at different substrate concentration (in %). From the above graph, we can conclude that catalase was functional with its min
  • 2015 E.C., Q39 – A student has conducted an experiment using different enzymes to assess the enhancement of reaction rates under different conditions. She represents her results as indicated in the following table: Enzymes used Cofactors
  • 2015 E.C., Q69 – Which one of the following sentences is correct about apo-enzymes? They
  • 2014 E.C., Q57 – Consider the following reaction: Reactant A + Reactant B → Enzyme → Intermediate → Product AB + Enzyme? At which point are the chemical bonds weakened?
  • 2014 E.C., Q54 – Which one of the following is correct about the action of apoenzymes and coenzymes?
  • 2013 E.C., Q94 – If an enzyme from thermophilic bacteria, which catalyses glucose 6- phosphate into fructose 6-phosphate in the process of glycolysis, is subjected to below the optimum temperature, the rate of reaction will be decreased.
  • 2013 E.C., Q77 – Which one of the following statements explains how an enzyme lowers the activation energy of a reaction? By
  • 2011 E.C., Q65 – Which of the following factors affects enzyme activity without denaturing the enzyme molecule?
  • 2011 E.C., Q50 – Which of the following statements is NOT correct about the effect of temperature on enzymes.
  • 2010 E.C., Q7 – What dose an enzyme do to a chemical reaction that allows it to proceed optimally?
  • 2010 E.C., Q2 – Which of the following is NOT a characteristic of an enzyme?
  • 2010 E.C., Q71 – Significant change in Ph that can affect an enzyme molecule include
  • 2009 E.C., Q64 – How do heavy metal ions reduce the reaction rate of enzymes?
  • 2009 E.C., Q3 – What is the intermediate compound that is formed during an enzyme catalyzed reaction?
  • 2009 E.C., Q51 – Which of the following statement about enzyme is NOT correct?
  • 2009 E.C., Q86 – What is an apoenzyme?
  • 2008 E.C., Q41 – Which of the following should be done in order to remove an enzyme inhibition caused by a competitive inhibitor?
  • 2008 E.C., Q40 – In enzymes that contain non-protein organic molecules, in addition to the protein component, what is the protein component called?
  • 2006 E.C., Q22 – Which of the following is the common characteristic of all enzymes?