Tag: the origin of cells and cell division

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

Which of the following is main enzyme of plasma membrane?

  1. TPPase

  2. ATPase

  3. Peptidyl transferase

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

ATPase are a class of enzymes that catalyze the dephosphorylation of ATP into ADP and a free phosphate ion. This dephosphorylation reaction releases energy, which the enzyme harnesses to drive other chemical reactions that would not otherwise occur. This process is widely used in all known forms of life. Such enzymes are integral membrane proteins anchored within biological membranes (plasma membrane), and move solutes across the membrane, typically against their concentration gradient.

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

An enzyme which catalyses the conversion of aldose sugar to ketose would be classified as

  1. Transferases

  2. Isomerases

  3. Hydrolases

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

Isomerases are the enzymes which catalyse transfer of groups within molecules to yield isomeric bonds. As aldose and ketose sugars are isomers, their interconversion is catalyzed by isomerases.

Transferases will catalyze group transfer reactions. 
Hydrolases will catalyze hydrolytic reactions and ligases catalyze formation of C-C, C-S, C-O and C-N bonds by condensation reactions coupled to ATP cleavage.

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

Which one of them catalyzes oxidation-reduction reactions?

  1. Oxidase

  2. Oxidoreductase

  3. Oxygenase

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

Certain enzymes carry oxidation reduction reactions. Oxidation is defined as the chemical process which involves loss of electron whereas reduction is the process in which a substrate accepts electron.
An oxygenase is any enzyme that oxidizes a substrate by transferring the oxygen from molecular oxygen O$ _2$ (as in air) to it.

An oxidoreductase is an enzyme that catalyzes the transfer of electrons from one molecule, the reductant, also called the electron donor, to another, the oxidant, also called the electron acceptor.
An oxidase is any enzyme that catalyzes an oxidation-reduction reaction, especially one involving molecular oxygen (O$ _2$) as the electron acceptor.

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

Peptidyl transferase enzyme found on 

  1. Cytoplasm

  2. E.R

  3. Golgi body

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

The peptidyl transferase is an aminoacyltransferase, it performs the primary enzymatic function of the ribosome, which forms peptide bonds between adjacent amino acids using tRNAs during the translation process of protein biosynthesis. Peptidyl transferase activity is carried out by the ribosome. Peptidyl transferase activity is not mediated by any ribosomal proteins but by ribosomal RNA (rRNA), a ribozyme. 

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

Carbonic anhydrase is the best known example of 

  1. Hydrolase

  2. Transferase

  3. Lyase

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

Lyase are the enzymes which catalyze breakdown reactions without hydrolysis. Lyases are classified as EC 4 in the EC number classification of enzymes. Lyases can be further classified into several subclasses : EC 4.1 includes lyases that cleave carbon-carbon bonds, such as decarboxylases (EC 4.1.1), aldehyde lyases (EC 4.1.2), oxo acid lyases (EC 4.1.3) and others (EC 4.1.99).

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. Peptidase

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

Enzymes are biological catalysts which catalyze biological reactions. They do not modify the chemical equilibria in any manner but simply make the attainment of equilibrium faster. Carbonic anhydrase catalyzes reversible reaction between carbon dioxide and water to form carbonic acid. This enzyme is one of the fastest enzyme. It is especially abundant in human erythrocytes.

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

First discovered enzyme was

  1. Isomerase

  2. Transaminase

  3. Zymase

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

Enzymes are biological catalysts, which activate various biochemical reactions of a living cell in a highly specific and precise manner. Enzymology is the study of enzymes. The name enzyme was coined by Kuhne in 1878. Pasteur recognised that some microorganisms like yeasts have got a capacity to cause fermentation in wine. In 1897, Buchner discovered that yeast extract could bring about fermentation of grape juice, like the living yeast cells. He also observed that the extract has lost its catalytic activity on boiling. He coined the word zymase for the active principle involved in the fermentation. The substance on which the enzyme acts is called substrate. Enzymes are essentially proteins but all proteins are not enzymes.

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

Enzymes, vitamins and hormones can be classified into a single category of biological chemicals, because all of these

  1. Are exclusively synthesized in the body of a living organism as at present.

  2. Enhance oxidative metabolism.

  3. Are conjugated proteins.

  4. Help in regulating metabolism.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation
There are more than thousand of biomolecules involve in living organisms in various biological processes. Some are vitamins, hormones, enzymes, ATP, carbohydrates, lipids, nucleic acids and proteins. Out of these main carbohydrates, proteins, lipids and nucleic acid are main biomolecules which play a vital role in living systems and mainly responsible for almost all biochemical processes. The biological molecules or biomolecules are involved in metabolic activities of living bodies such as plants and animals. Most of the biomolecules in the living cell have some broad functions like:
1. They are essential to cellular and body structure.
2. They act as energy-rich fuels during cellular respiration.
3. The molecules are used to carry information of controlling growth and biological characteristics from one generation to another.
4. They are good catalytic agents for the various chemical processes occur in cell and living body.
Multiple choice biology enzymes classification of enzyme enzymes classification and cofactors the origin of cells and cell division

Ribozymes are 

  1. RNA acting as enzymes.

  2. Antibody acting as enzymes.

  3. Ribosomes acting as enzymes.

  4. None of the above.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Enzymes are biological catalysts which speed up the biological reactions. All metabolic reactions in a cell are catalyzed by enzymes. Almost all enzymes are proteins. There are some nucleic acids that behave like enzymes. These are called ribozymes. Ribozymes are molecules of ribonucleic acid with catalytic activity.