Tag: cell biology and biotechnology

Tracer elements are radioisotopes which are used to trace the path of molecules in metabolic pathways. Thus elucidating the metabolic pathway. For example an important experiment proving that DNA carries genetic information, was based on tracer techniques. In 1952 Alfred D. Hershey and Martha Chase used radioactive phosphorus (32P) and radioactive sulfur (35S) tracers to show that when the bacterial virus (bacteriophage)T2 infects its host cell, Escherichia coli, it is the phosphorus-containing DNA of the viral particle, not the sulfur-containing protein of the viral coat, that enters the host cell and furnishes the genetic information for viral replication.

A water molecule has two hydrogen and one oxygen atom and is smallest among the given options. An enzyme can be as small as a chain of 60 amino acid residues, while a bacterium ranges in 1 micrometre in diameter. The chromosome contains linear DNA molecule which is 2 m long. Nucleus diameter is  6 micrometers. The correct ascending order of size is water molecule, enzyme, bacterium, chromosome and nucleus. 

DNA is chemically less reactive as compared to RNA.
RNA mutate at a faster rate because from DNA, RNA is formed duirng transcription and there are more chances of mutation during this phase.
Saccharin is an artificial sweetener with effectively no food energy which is about 300-400 times as sweet as sucrose.
hnRNA is heterogenous nuclear RNA. Its processing includes addition of a cap. The cap is 5'methyl guanosine that is added immediately after the start of the transcription. This reaction is catalysed by guanylyl transferase.

Carbohydrates are the primary cellular fuel used to derive energy. Fats and proteins are used under starvation when carbohydrates are not available. Vitamins are not a major source of energy but are required as coenzymes for many enzymatic reactions in body metabolism.

Polymerisation is the process by which the simpler units known as monomers attach with the help of chemical bond to form a long chain or branched structure. It helps to produce new chemicals like glycogen, cellulose, fatty acids etc. The complex molecules (e.g. glycogen) are large in size and are unable to cross the semipermeable membrane by the process of osmosis. So they are osmotically inactive. These large size molecules which are used mainly for storage is broken down into simple molecules for metabolic need.  So, the correct answer is option D.

Biochemistry is the study of chemical processes within and relating to living organisms It focuses on understanding how biological molecules give rise to the processes that occur within living cells and between cells which in turn relates greatly to the study and understanding of tissues, organs, and organism structure and function. Biochemical processes give rise to the complexity of life. Hence, the study of the physicochemical nature of bio-molecules is biochemistry.

Galactose is a monosaccharide which is also known as brain sugar. It is an important constituent of glycoprotein and glycolipids.

Carbohydrate, on the basis of the number of molecules present, is divided into monosaccharides, disaccharide and polysaccharides. Fructose is also known as the fruit sugar and is a monosaccharide. It is a 6 carbon molecule. Glycine is the simplest amino acid as it contains hydrogen in the side chain. Lactose is a disaccharide which means it has two molecules of same or different monosaccharide units. Lactose is also known as the milk sugar. 

Macromolecules are the molecules made by the attachment of micro molecule. These are complex molecules. Cellulose, DNA, and glycogen are macromolecules as they are formed by linkage of simple monomers.

Polymerization is the process by which the simpler unit known as monomers attaches with the help of chemical bond to form a long chain or branched structure. It helps to produce new chemicals. It is a process of joining repeating units to form a macromolecule is known as polymerization. For example, proteins are building blocks of the body. The proteins are made up of amino acids. The amino acids are linked together by peptide bonds to form a protein.