Tag: enzymes

Quizzes (4) Questions (199)

Questions Related to enzymes

Multiple choice biology enzymes classification of enzyme enzymes classification and cofactors the origin of cells and cell division

Lactose metabolising enzyme, produced in the presence of lactose only is

  1. Inducible enzyme

  2. Repressible enzyme

  3. Regulatory enzyme

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

Inducible enzymes are synthesized only in the presence of their specific substrate, such as the enzymes of the lac operon in the presence of lactose.

Multiple choice biology enzymes classification of enzyme enzymes classification and cofactors the origin of cells and cell division

Match List I with List II and select the correct answer.

List-I(Enzymes) List-II(Characteristic Activity)
a. Terminal transferees $1$. Stable above $90$ degrees C
b. Polynucleotide kinesis $2$. Cleave the ends of linear DNA
c. Taq DNA polymerases $3$ Adds phosphate to $5$ OH end of DNA or RNA
d. Exonucleases $4$. Adds a number of nucleotides to $3'$ end of DNA or RNA
$5$. Regulate the level of super coiling of DNA molecule
  1. A-$5$, B-$4$, C-$1$, D-$2$
  2. A-$4$, B-$3$, C-$1$, D-$2$
  3. A-$3$, B-$4$, C-$5$, D-$1$
  4. A-$4$, B-$3$, C-$2$, D-$1$
Reveal answer Fill a bubble to check yourself
B Correct answer
Multiple choice biology enzymes classification of enzyme enzymes classification and cofactors the origin of cells and cell division

Enzymes catalysing removal of group and formation of double bonds are 

  1. Ligases

  2. Lyases

  3. Transferases

  4. Oxidoreductases
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Lyases is an enzyme which catalyses the joining of specified molecules or groups by a double bond. Lyases catalyze reactions where functional groups are added to break double bonds in molecules or the reverse where double bonds are formed by the removal of functional groups. So, the correct answer is option B.

Multiple choice biology enzymes classification of enzyme enzymes classification and cofactors the origin of cells and cell division

The catalytic efficiency of two different enzyme can be compared by the:

  1. The Kim value

  2. The pH optimum value

  3. Formation of the product

  4. Molecular size of the enzyme
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
The $K _m$ is also known as Michaelis-Menten constant. It represents the substrate concentration at which the rate of a reaction is half the maximum rate. It is an important parameter to compare catalytic efficiency of two enzymes. Lower the $K _m$ , higher will be the catalytic rate and vice-versa.
Multiple choice biology enzymes classification of enzyme enzymes classification and cofactors the origin of cells and cell division

The fastest acting enzyme in the biological kingdom is

  1. Lipase

  2. Amylase

  3. Carboxypeptidase

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

In enzymology, turnover number is the number of substrate molecules converted to products in a given unit of time on a single enzyme molecule when the enzyme is saturated with substrate. The enzyme catalase has highest turnover number value of 40,000,000 (per second per molecule of enzyme), followed by Carbonic anhydrase 400,000 (per second per molecule of enzyme), followed by acetylcholinesterase 140,000 (per second per molecule of enzyme), followed by $\beta$-lactamase 2000 (per second per molecule of enzyme).

Multiple choice biology enzymes classification of enzyme enzymes classification and cofactors the origin of cells and cell division

Match the scientists and their contribution given in the columns.


Scientists Contribution
A. Pasteur p. Beer and butter milk are products of fermentation by yeast
B. Hansen q. Diastase
C. Payen and Persoz  r. Purified rennet 
D. Waksman s. Streptomycin

  1. A - p, B - q, C - r, D - s

  2. A - p, B - r, C - q, D - s

  3. A - p, B - s, C - r, D - q

  4. A - s, B - r, C - q, D - p
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The scientists listed in question had made some of the most outstanding contributions.
Pasteur discovered fermentation.  The biochemical process carried out by yeast which results in fermented products like beer and butter milk.
The first commercial standardized rennet was introduced by Chr Hansen in 1874. At that time, rudimentary methods were used to extract animal rennet from calves or adult bovine stomachs.
Diastase was the first enzyme discovered. It was extracted from malt solution in 1833 by Anselme Payen and Jean-Franois Persoz, chemists at a French sugar factory.
Waksman was awarded the Nobel Prize in Physiology or Medicine in recognition for his discovery of streptomycin, the first antibiotic active against tuberculosis.