Tag: properties of enzyme

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Multiple choice properties of enzyme enzyme properties enzymes biomolecules: chemical constituents of living cells biology

Nobel Prize for discovering enzymes was given to 

  1. Kuhne

  2. Duclaux

  3. Buchner

  4. Dubrunfaut
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
Biocatalysts were found accidentally in yeast extract by Buchner in 1897. He prepared a yeast extract and added sugar solution to it. After some time he noticed the alcohol formation in the extract which was a sign of fermentation which took in presence of enzyme. Later on, summer crystallized an enzyme known as urease and reported that all enzymes are protein.
So, the correct answer is option C.
Multiple choice properties of enzyme enzyme properties enzymes biomolecules: chemical constituents of living cells biology

Enzymes are basically made of

  1. Nucleic acids

  2. Proteins

  3. Fats

  4. Vitamins
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
Enzymes are proteins which help to catalyze the biochemical reaction. The enzyme has a protein part which is not active is known as apoenzyme. It gets activated by the addition of an organic or inorganic cofactor. The holoenzyme is defined as apoenzyme in combination with the cofactor. 
So, the correct answer is option B.
Multiple choice properties of enzyme enzyme properties enzymes biomolecules: chemical constituents of living cells biology

Who confirmed protein nature of enzymes?

  1. Monod et al

  2. Arber et al

  3. Berzelius

  4. Northrop
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
The proteinous nature of enzyme was proved by Sumner, John Howard Northrop, and Wendell Meredith Stanley. Enzymes are proteins which help to catalyze the biochemical reaction. The enzyme has a protein part which is not active is known as apoenzyme. It gets activated by the addition of an organic or inorganic cofactor. The holoenzyme is defined as apoenzyme in combination with the cofactor. 
So, the correct answer is option D.
Multiple choice properties of enzyme enzyme properties enzymes biomolecules: chemical constituents of living cells biology

An enzyme acts by

  1. Reducing the energy of activation.

  2. Increasing the energy of activation.

  3. Decreasing the pH.

  4. Increasing the pH.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The reactants do not undergo chemical change automatically. They do so in transition state. Transition state has more free energy than reactants or products. The inability of reactants to undergo change due to requirement of extra energy for converting them to transition state is called as 'Energy Barrier'. Energy required to overcome energy barrier is called as 'Activation Energy'.

Multiple choice properties of enzyme enzyme properties enzymes biomolecules: chemical constituents of living cells biology

The suffix $-ase$ to enzyme names was proposed by

  1. Duclaux

  2. Buchner

  3. Northrop

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

The suffix -ase  is used for the nomenclature of the enzyme. It is used at the end of the substrate. For example, the enzyme that breaks down peroxides are known as peroxidases. Hexokinase are the enzyme which helps in synthesis of hexose sugar. In 1898 Duclaux proposed the suffix -ase.

So, the correct answer is option A.

Multiple choice properties of enzyme enzyme properties enzymes biomolecules: chemical constituents of living cells biology

Many enzymes are secreted in inactive form to protect

  1. Cell proteins

  2. Mitochondria

  3. Cell membrane

  4. Cell DNA
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The enzymes are protein in nature and they are generally produced in inactive form so to protect the intracellular damage of protein. For example,  digestive enzymes are secreted in form of zymogens which remains inactive in the cells in which it is produced. The active sites are blocked by the peptide which keeps the enzyme in the inactive stage so the other proteins do not get harmed by the reaction. Cleavage of this peptide cleaves activates the enzyme.

So, the correct answer is option A. 

Multiple choice properties of enzyme enzyme properties enzymes biomolecules: chemical constituents of living cells biology

Which is not a trait of enzymes?

  1. Proteinaceous nature

  2. Specific in nature

  3. Speed up rate of biochemical reaction

  4. Used up in reaction
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Enzymes are proteins which help to catalyze the biochemical reaction. The enzyme has a protein part which is not active is known as apoenzyme. It gets activated by the addition of an organic or inorganic cofactor. It is specific in nature as specific substrate bind at the active site of a particular enzyme. It increases the rate of chemical reactions without being used up. The enzymes lower the activation energy and lead to the formation of activated complex, which is also known as transition state and finally changes to the product.

So, the correct answer is option D.

Multiple choice properties of enzyme enzyme properties enzymes biomolecules: chemical constituents of living cells biology

Enzymes exist in the cells as

  1. Solid

  2. Crystals

  3. Solution

  4. Colloid
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Enzymes are proteins which help to catalyze the biochemical reaction. The enzyme has a protein part which is not active is known as apoenzyme. It gets activated on the addition of an organic or inorganic cofactor. It exists as hydrophilic colloid in the cytoplasm which makes it inert and prevents its dissociation. The hydrophilic part of the colloid is present on the surface which interacts with the water. 

Multiple choice properties of enzyme enzyme properties enzymes biomolecules: chemical constituents of living cells biology

Which is wrong about enzymes?

  1. Enzymes are mostly proteins but some are lipids also

  2. Enzymes are highly specific

  3. Enzymes require optimum pH and temperature for maximum activity

  4. Enzymes are denatured at high temperature
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
Enzymes are made up of proteins which accelerates the rate of the reaction. It lowers the activation energy and converts the reactants into the substrate. The increased temperature increases the kinetic energy of the enzymes which further accelerates the activity of the enzyme but at the higher temperature, it gets denatured as the peptide bonds between the proteins molecules breaks which disrupts the structure of enzymes. 
Enzymatic activity depends on specific pH. pH at which the enzyme has maximum activity is known as optimum pH. The change in pH changes the shape of the enzyme which prevents the attachment of the substrate at the active site and terminates the reaction. 
Enzymes are specific in nature. It forms an enzyme-substrate complex by attaching to the active site of the enzyme which depends specifically on the shape of the active site and the substrate molecules.
So, the correct answer is option A.
Multiple choice properties of enzyme enzyme properties enzymes biomolecules: chemical constituents of living cells biology

Which is true about enzymes?

  1. All enzymes are not proteins

  2. All enzymes are vitamins

  3. All enzymes are proteins

  4. All proteins are enzymes
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Enzymes are protein in nature. But some enzymes like ribozymes and ribonuclease are RNA based enzymes. It is also known as ribonucleic acid enzymes. These are RNA molecules which helps in the catalysis of a particular reaction. It was discovered in year 1982. The RNA can act as both genetic material and can act as a biocatalyst but different from protein-based enzymes. It acts as a part of ribosome which attaches to the amino acid during protein synthesis. Thomas R. Cech and Sidney Altman discovered catalytic properties of RNA. So, the correct answer is option A.