Tag: catalysis

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Questions Related to catalysis

Multiple choice chemistry surface chemistry enzyme catalysis catalysis proteins and enzymes

Which one of the following statements is false?

  1. Enzymes arc highly specific

  2. Enzymes increase activation energy

  3. Enzymes require optimum temperature

  4. None of the above
Reveal answer Fill a bubble to check yourself
A,C Correct answer
Explanation
  • Enzymes serve as a biological catalyst by accelerating the rate of chemical reaction occurring inside the cells of living organisms, thus decreasing the activation energy required for the reaction to occur. 
  • Enzymes are very specific in nature, implying that, a particular enzyme can catalyze only a specific reaction and not all the reactions. 
  • The optimum temperature for an enzyme to function effectively is $37.5^o C$ which is also the normal human body temperature. At a temperature above this, enzymes undergo denaturation, thus, showing a reduced performance
Multiple choice chemistry surface chemistry enzyme catalysis catalysis proteins and enzymes

Which of the following catalysts is sensitive to temperature changes?

  1. Enzymes
  2. $Pt, Fe$
  3. $Ni, Fe$

  4. All of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Enzymes are specific in their action and catalyze reactions at lower temperature. At high temperature, they lose their specific nature and get denatured.

Multiple choice chemistry surface chemistry enzyme catalysis catalysis proteins and enzymes

The function of zymase is to: 

  1. change starch into sugar

  2. ferment glucose to alcohol and carbon dioxide

  3. change malt sugar into glucose

  4. change starch into malt sugar and dextrin
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Zymase is an enzyme complex that catalyzes the fermentation of sugar into ethanol and carbon dioxide.
Hence option B is correct.

Multiple choice chemistry surface chemistry enzyme catalysis catalysis proteins and enzymes

The enzyme ptyalin used for digestion of food is present in: 

  1. saliva

  2. blood

  3. intestine

  4. adrenal glands
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The enzyme ptyalin, also known as amylase is present in saliva and is responsible for breaking down starch into simple sugars such as dextrin and maltose which are further broken down in the intestine

Multiple choice chemistry surface chemistry enzyme catalysis catalysis proteins and enzymes

The function of enzymes in the living system is to________.

  1. Transport oxygen

  2. Provide immunity

  3. Catalyse biochemical reaction

  4. Provide energy
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The function of enzymes in the living system is to catalyse biochemical reaction.
Enzymes are highly substrate specific and catalyze reactions by providing an alternate pathway of lower activation energy.

Multiple choice chemistry surface chemistry enzyme catalysis catalysis proteins and enzymes

A catalyst increases the rate of reaction by_________.

  1. Decreasing enthalpy

  2. Decreasing internal energy

  3. Decreasing activation energy

  4. Increasing activation energy
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

A catalyst increases the rate of reaction by decreasing activation energy.
Note: The function of enzymes in the living system is to catalyse biochemical reaction.
Enzymes are highly substrate specific and catalyze reactions by providing an alternate pathway of lower activation energy.

Multiple choice chemistry surface chemistry enzyme catalysis catalysis proteins and enzymes

 Identify the correct statement regarding enzymes:

  1. Enzymes are specific biological catalysts that can normally function at very high temperature

  2. Enzymes are normally heterogeneous catalysts that are very specific in action.

  3. Enzymes are specific biological catalysts that cannot be poisoned

  4. Enzymes are specific biological catalysts that possess well defined active site
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Enzymes are specific biological catalysts that possess well defined active site.
Enzymes function at physiological temperature $ \displaystyle \simeq (37 : ^oC)$


Enzymes can be poisoned using suitable inhibitors.

Hence, the correct option is $\text{D}$

Multiple choice chemistry surface chemistry enzyme catalysis catalysis proteins and enzymes

Which of the following statements regarding enzyme inhibition is correct -

  1. Competitive inhibition is seen when a substrate competes with an enzyme for
    binding to an inhibitor protein

  2. Non-competitive inhibitors often bind to the
    enzyme irreversibly

  3. Competitive inhibition is seen when the substrate and the inhibitor compete for the active site on the enzyme

  4. Non-competitive inhibition of an enzyme can be overcome by adding large amount of substrate
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
Competitive inhibition is seen when the substrate and the inhibitor compete for the active site on the enzyme because competitive inhibitor has a similar structure as that of a substrate, so it blocks the active site of an enzyme thereby reducing the production formation.
Multiple choice chemistry surface chemistry enzyme catalysis catalysis proteins and enzymes

Enzymes, which catalyze biochemical reactions are very complex. They help in the reaction of very specific substances. This suggests that the enzyme and the reacting biochemicals are complementary to one another like a:

  1. dog in his kennel

  2. horse and a rider

  3. lock and key

  4. leaf and a bud
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Enzymes are very specific in nature. Only those substrates that can fit into the active site of an enzyme can be bound within it. This specific action is similar to a lock and key where a key(reacting biochemicals) can only be used to actuate a specific lock(enzyme) and not all of them.