Tag: the origin of cells and cell division

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

Ribozyme is

  1. RNA with additional phosphate.

  2. RNA without sugar.

  3. RNA without uracil.

  4. RNA acting as enzyme.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Most of the enzymes are large protein molecules except for a small category of catalytic RNA molecules. The catalytic RNA molecules are called Ribozymes. Ribozymes play an important role in intron splicing and other reactions during processing of RNA. The ribozymes are an important example of self catalytic (RNA) molecules, i.e., one type of RNA (ribozyme) acting on another type of RNA (like mRNA). Some of the introns are self splicing which catalyze their own splicing.

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

Digestive enzymes are found in

  1. Lysosomes

  2. Mitochondria

  3. Chloroplast

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

Lysosomes are membrane-bound vesicles that contain digestive enzymes, such as glycosidases, proteases and sulfatases. Lysosomal enzymes are synthesized in the endoplasmic reticulum (ER), are transported to the Golgi apparatus, and are tagged for lysosomes by the addition of mannose-6-phosphate label. Digestive enzymes are not found in chloroplast and mitochondria. 

Therefore, the correct answer is option A.

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

Enzymes that catalyse inter-conversion of optical, geometrical or positional isomers are

  1. Ligases

  2. Lyases

  3. Hydrolases

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

Ligases are the enzymes which catalyze joining together of two DNA segments. Lyases catalyze the breaking of chemical bonds without hydrolysis while hydrolases catalyze hydrolytic cleavage of bonds. Isomerases catalyze interconversion of optical, geometrical or positional isomers of a particular enzyme.

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

Endopeptidase of plant kingdom is

  1. Trypsin

  2. Pepsin

  3. Papain

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

Endopeptidase are the proteolytic enzymes which cleave the peptide chain at internal locations. They break peptide bonds of non terminal amino acids (i.e. within the molecule), in contrast to exopeptidases, which break peptide bonds from their end-pieces. One example is papain obtained from unripe papaya.

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

One of the following enzyme is used to cut genes at specific sites, therefore, useful in recombinant technology

  1. Ligase

  2. Topoisomerase

  3. Pepsin

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

Restriction endonuclease are a part of cellular defense system in bacteria. These enzymes cleave or restrict external or exogenous DNA. A type of these enzymes act on specific palindromic sequences which they recognize.

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

An organic substance bound to an enzyme and essential for its activity is called as

  1. Apoenzyme

  2. lsoenzyme

  3. Coenzyme

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

Enzymes are simple if they are made up of only proteins, e.g., pepsin, amylase, etc., while conjugate enzymes have an additional non-protein cofactor, e.g., dehydrogenase enzymes. The cofactor can be organic or inorganic. Loosely attached organic cofactor are called coenzymes, e.g., NAD, FAD etc., while firmly attached one is prosthetic group, e.g., haeme, biotin etc.