Biomolecules Test - 45

• In 1897, Eduard Buchner discovered that yeast extracts could ferment sugar to alcohol, proving that fermentation was promoted by molecules that continued to function when removed from cells. Frederick W. Khne called these molecules like enzymes.
  Hence, the correct option is B.

Nucleic acids are heterocyclic compounds with rings containing nitrogen and carbon. They are biopolymers and are of two types as DNA (deoxyribonucleic acid) and RNA (ribonucleic acid). RNA helps in protein synthesis in association with ribosomes. DNA stores hereditary information in the form of code words and passes it to the next generation. 

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.

All reactions, whether exergonic or endergonic, have an energy barrier known as the energy of activation (E A), or activation energy, which is the energy required to break the existing bonds and begin the reaction. In a population of molecules of any kind, some have a relatively high kinetic energy, whereas others have a lower energy content. Only molecules with a relatively high kinetic energy are likely to react to form the product. Even a strongly exergonic reaction, one that releases a substantial quantity of energy as it proceeds, may be prevented from proceeding by the activation energy required to begin the reaction. For example, molecular hydrogen and molecular oxygen can react explosively to form water. This reaction is spontaneous, yet hydrogen and oxygen can be safely mixed as long as all sparks (source of energy) are kept away, because the required activation energy for this particular reaction is relatively high. A tiny spark provides the activation energy that allows a few molecules to react. Their reaction liberates so much heat that the rest react, producing an explosion.

Enzymes are proteins that act as catalysts and help complex reactions occur everywhere in life. These are polypeptides. Chemically, peptide linkage is an amide formed between –COOH group and –NH2 group.

Cellular respiration is the set of metabolic processes that take place in the cells. In this process glucose is oxidized through the metabolic pathways like glycolysis in cytoplasm and Krebs's cycle in mitochondria and produces energy in the form of ATP. ATP is further utilized by the different cell for their activities.