Biology - Grade 12 - 2022 G.C
56 . Which one of the following is an example of social behavior?

  1. Exaggeration of size by fluffing up of feathers
  2. Singing of frogs on spring nights
  3. Marking a territory with urine
  4. Caring for offspring that are not one's own


57 . Consider the following reaction.
Reactant A + Reactant B + Enzyme Intermediate → Product AB + Enzyme?
At which point are the chemical bonds weakened? At the

  1. intermediate
  2. reactant A
  3. reactant B
  4. product AB


58 . How do enzymes bind and act on their substrates? By using the

  1. lock-and-key model and reducing energy of the substrate
  2. induced-fit model and providing extra energy for the substrate
  3. lock-and-key model and changing themselves into products
  4. induced-fit model and putting the substrates under tension


59 . Which of the following external factors influence the turnover rate of enzymes by completely damaging their tertiary structure?

  1. Competitive inhibitors
  2. Substrate concentration
  3. Reversible inhibitors
  4. Temperature and pH


60 . During baking of injera, the CO₂ produced by yeast is used to

  1. kill contaminants that spoil injera.
  2. give injera its typical texture.
  3. bake injera with low temperature.
  4. increase the shelf life of injera.


We have provided these questions from previous years grade 12 Ethiopian Secondary School Leaving Certificate Examination (ESSLCE) exams with the sole purpose of assisting students in their studies and preparations for upcoming exams. Please be aware that these questions are not indicative of future exam content. Good luck with your studies!

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