Tag: enzyme properties

Quizzes (0) Questions (62)

Questions Related to enzyme properties

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

Enzymes functional in a cell are

  1. Inducible, constitutive and repressible

  2. Inducible and repressible

  3. Inducible only

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

Enzymes are inducible in nature because as the substrate molecules attaches to the active site of the enzyme, it induces a conformational change on the active site to fit in properly.

Constitutive protein are the protein which are constantly active. Enzymes are said to be consitutive in nature as they remain active till the end of the reaction and catalyzes the reaction without being used up.
Enzymes are repressible because their actions can be controlled by addition of an inhibitor or by regulating conditions like temperature, substrate concentration and its pH.
So, the correct answer is option A.

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

Most of hydrolytic reactions are

  1. Exothermic

  2. Endothermic

  3. Irreversible

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

Hydrolytic reactions are the reactions which involves breaking of the bond by the addition of water. It can be reversed by the condensation reaction where the joining of two molecule leads to release of water by formation of bonds. Saccharification is the reaction where the complex sugar molecule is broken into its component sugar molecules by hydrolysis. It can be reversed by condensation reaction.

So, the correct answer is option D.

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

Enzyme generally have?

  1. Same pH and temperature optima

  2. Same pH but different temperature optima

  3. Different pH but same temperature optima

  4. All wrong
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The optimum temp of enzymes is 20-35°C. They become inactivated at very low temperature and denatured (destroyed) at very high temp i.e. greater than 45°C. Low molecular weight enzymes are comparatively more heat stable. In archaebacterium Pyrococcus furiosus, the optimum temperature of hydrogenase is greater than 95°C. This heat-stable enzyme enables Pyrococcus to grow at 100°C. The optimum pH of most endoenzyme is pH 7.0 (neutral pH). However, digestive enzymes can function at different pH. For example, salivary amylase act best at pH 6.8, pepsin act best at pH2 etc. Any fluctuation in pH from the optimum causes ionization of R-groups of amino acids which decrease the enzyme activity.

So the correct option is 'different pH but same temperature optima' 

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

Serine proteases are called so because they

  1. They require serine for their activity

  2. cleave after serine residues in the substate

  3. Are inhibited by the presence of free serine

  4. Have a serine residue at their active sire
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Serine proteases are enzymes that cleave peptide bonds in proteins, in which serine serves as a nucleophilic amino acid at enzyme's active site. Serine proteases are responsible for coordinating various physiological functions including digestion, immune response, blood coagulation, and reproduction. Hence, serine proteases are called so because they require serine for their activity.

So, the correct answer is 'They require serine for their activity'.

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

Specific enzymes are needed for the break-down of a particular substance.

  1. True

  2. False

  3. Either

  4. Neither
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
Enzymes are very specific for the substances they act upon and cause their breakdown. For example, cellulase enzyme breakdowns cellulose, protease enzyme breakdowns proteins, pectinase enzyme breakdowns pectin, hemicellulose enzyme breakdowns hemicellulose and many more such enzymes are there. Enzymes are biological catalysts which increase the rate of reaction by lowering the energy of activation. High specificity is a characteristic feature of enzymes.
Hence, the statement given in the question is correct.
So, the correct answer is 'True'
Multiple choice properties of enzyme enzyme properties enzymes biomolecules: chemical constituents of living cells biology

Mark the INCORRECT statement about the enzyme carboxypeptidase.

  1. Zinc is the co-factor for this proteolytic enzyme

  2. It is exopeptidase

  3. It cleaves the peptide bond at N-terminal end of the polypeptide chain

  4. It is an enzyme of pancreatic juice
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Carboxypeptidase is a pancreatic exopeptidase that cleaves peptide bonds at the C-terminal end of a polypeptide chain, not the N-terminal end. Thus, statement C is incorrect.

Multiple choice properties of enzyme enzyme properties enzymes biomolecules: chemical constituents of living cells biology
Which of the following is an example of isozyme?
  1. $\alpha$-amylase

  2. Glucokinase

  3. Lactate dehydrogenase

  4. All of the above

Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
The multiple molecular forms of an enzyme occurring in the same organism and having a similar substrate activity are called isoenzymes or isozymes. They have similar properties but different molecular weights and locations. Over 100 enzymes are known to have isoenzymes. $\alpha$-amylase of wheat endosperm, has 16 isozymes, lactate dehydrogenase has 5 isozymes. Glucokinase is an isozyme of hexokinase.
So, the correct answer is 'All of the above'.
Multiple choice properties of enzyme enzyme properties enzymes biomolecules: chemical constituents of living cells biology

The active site of an enzyme is formed by

  1. Exposed sulphur bonds

  2. Side chains of the amino acids

  3. Amino groups of the amino acids

  4. Carboxyl group of the amino acids
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The enzyme active site is composed of the amino acid residues. Side chains of the amino acids are seen in the active site region of the enzyme. The difference in the identity, charge, and spatial orientation of the functional groups located there results in the difference in enzyme specificity. 

So, the correct option is ' side chains of amino acids'.

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

Read the following statement
(i) The enzymes acts on 'N' terminal of a polypeptide chain is present in A
(ii) The enzymes in 'C' terminal of a polypeptide chain is present in BChoose the option which correctly fills up the blanks
A and B

  1. Gastric juice Pancreatic juice

  2. Pancreatic juice Gastric juice

  3. Pancreatic juice Succus entericus

  4. Intestine juice Pancreatic Juice
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
The Pancreatic juice containing carboxypeptidases cleave the amino acid from the peptides from the carboxyl-terminal or C terminal.
The aminopeptidases present in the succus entericus cleave the amino acid from the amino-terminal or the N-terminal.

So, the correct answer is 'Pancreatic juice Succus entericus'