Tag: enzymes

Questions Related to enzymes

Which of the following set of three items are true, as each set belongs to the category mentioned against them?

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

  1. Lysine, glycine, thiamine - Amino acids

  2. Myosin, oxytocin and gastrin - Hormones

  3. Rennin, helicase and hyaluronidase - Enzyme

  4. Optic nerve, oculomotor, vagus - Sensory nerves

Show answer
Correct Option: C
Explanation:

Rennin is a protease found in rennet. It is produced by newborn ruminant animals in the lining of the fourth stomach to curdle the milk they ingest, allowing a longer residence in the bowels and better absorption. It is widely used in the production of cheese.

Helicases are enzymes that bind and may even remodel nucleic acid or nucleic acid protein complexes. There are DNA and RNA helicases. DNA helicases are essential during DNA replication because they separate double-stranded DNA into single strands allowing each strand to be copied.
Hyaluronidase is a protein enzyme. It works by causing rapid spreading of injected fluid into the body, which increases the absorption of injected fluids.
Therefore, the correct answer is option C.

Enzyme concerned with transfer of electrons are

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

  1. Hydrolase

  2. Dehydrogenase

  3. Transaminase

  4. Protease

Show answer
Correct Option: B
Explanation:

Dehydrogenases are the enzymes which catalyze oxidation-reduction reactions by addition or removal of electrons. These reactions are used to synthesize reduced coenzymes like NADH$ _2$ and FADH$ _2$. For example phosphoglyceraldehyde dehydrogenase.

So, the correct answer is 'Dehydrogenase'.

Which enzyme shows greatest substrate specificity?

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

  1. Nuclease

  2. Trypsin

  3. Sucrase

  4. Pepsin

Show answer
Correct Option: C
Explanation:
Enzymes are highly specific catalysts and show high degree of substrate specificity. Some enzymes names are general and these enzymes act on a type of biomolecules. For example: nucleases means enzymes acting on nucleic acids. Nuclease is a general class of enzyme. Similarly, pepsin and trypsin are protein metabolising enzymes. These enzymes will act on any proteins and not on some specific protein. Sucrase is, however, a specific enzyme which will act on sucrose only.
So, the correct answer 'Sucrase'

Non-proteinaceous enzyme that acts as a catalyst for the formation of peptide bond is
OR
"All enzymes are proteins." This statement is now modified because an apparent exception to this biological truth is

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

  1. Spliceosome

  2. Ribozyme

  3. RNA polymerase I

  4. RNA polymerase III

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Correct Option: B
Explanation:

Ribozymes or RNA enzymes are catalytic RNA molecules. The first ribozyme discovered was self splicing group I intron. The second catalytic RNA was RNAase P which separates tRNA from hn RNA at their 5' ends. Peptidyl transferase involved in translation of proteins is also catalytic RNA. Telomerase is a ribonulceoprotein  enzyme. It is involved in replication of terminal DNA or telomeres.

Molecular scissors which cut DNA at specific site is known as

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

  1. Pectinase

  2. Polymerase

  3. Restriction endonuclease

  4. Ligase

Show answer
Correct Option: C
Explanation:

A restriction enzyme or restriction endonuclease or molecular scissors is an enzyme used in genetic engineering that splices DNA at or near specific recognition nucleotide sequences, known as restriction sites. Thus, the correct answer is option C.

Which of the following enzyme is not of protein origin?

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

  1. Hexokinase

  2. Synthetase

  3. Endonuclease

  4. Ribozyme

Show answer
Correct Option: D
Explanation:

Enzymes are biological catalysts which catalyse the biochemical reactions in living systems. Majority of enzymes are proteins. A small minority of enzymes are catalytic RNA molecules. These catalytic RNA molecules are called ribozymes. These catalytic RNA molecules catalyze reactions like splicing of introns during processing of RNA in eukaryotic mRNA.

Telomerase is an enzyme which is a

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

  1. Simple protein

  2. RNA

  3. Ribonucleoprotein

  4. Repetitive DNA

Show answer
Correct Option: C
Explanation:
Telomerase is a ribonucleoprotein enzyme which adds bases at the 3' end of one strand of telomere as directed by the RNA sequence of RNA component of this enzyme.
So, the correct answer is 'Ribonucleoprotein'

Which of the following enzymes has/have heme as a prosthetic group?
(i) Catalase                            

(ii) Carboxypeptidase
(iii) Succinic dehydrogenase 

(iv) Peroxidase

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

  1. (i) Only

  2. (i) and (ii)

  3. (ii) and (iii)

  4. (iii) and (iv)

  5. (i) and (iv)

Show answer
Correct Option: E
Explanation:

Co-enzymes tightly or covalently bonded to enzymes are called prosthetic groups, e.g., pyridoxal phosphate, heme, biotin. Heme is a prosthetic group containing ferrous ion. It is important for a number of biologically important hemoproteins such as myoglobin, cytochrome oxidase, catalase and peroxidase. Thus, the correct answer is option E.

Which one of the following enzyme contains 'Mn' metallic ion as the prosthetic group?

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

  1. Phosphatase

  2. Dehydrogenase

  3. Peptidase

  4. Catalase

Show answer
Correct Option: C
Explanation:

Prosthetic groups are tightly bound cofactors. Peptidase enzymes hydrolyze peptide bonds. Peptidase enzymes require manganese ion for their activity as prosthetic group.

In which one of the following enzymes, is copper necessarily associated as an activator?

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

  1. Lactic dehydrogenase

  2. Tyrosinase

  3. Carbonic anhydrase

  4. Trytophanase

Show answer
Correct Option: B
Explanation:

Some enzymes require metal ions for their activity. Tyrosinase is a copper containing enzyme that catalyzes the production of melanin and other pigments.