Tag: biotechnology

Magnesium is an important macronutrient required by plants in large quantity. Magnesium is a constituent of chlorophyll pigment and is required as an essential cofactor for all the reactions catalysed by kinase enzymes like hexokinase. Magnesium is also important for structural integrity of ribosomes. Ribosomes are the cell organelles involved in protein synthesis.

The blood glucose level in body is tightly regulated by a number of mechanism. The normal blood glucose level in humans should not exceed 140 mg per decilitre after meals and is maintained between 70 to 100 mg per decilitre under fasting conditions without food. Glucose is a precious metabolite and, hence, is actively reabsorbed by the kidney tubules. Any excess quantity of glucose is converted into glycogen which is stored in liver and muscles. Any further excess is converted to fats and stored for long term deposit. In humans and most other mammals, acetyl CoA formed in the liver during oxidation of fatty acids may enter the citric acid cycle or may be converted to ketone bodies, i.e., acetoacetate, $\beta$-hydroxy-butyrate and acetone for export to other tissues. Overproduction of ketone bodies can occur in conditions of severe starvation and in uncontrolled diabetes.

The nerves responsible for sensing a stimulus and sending information about the stimulus to your central nervous system are called afferent neurons. The nerves that carry signals away from the central nervous system in order to initiate an action are called efferent neurons.

Sporopollenin is found in outer layer or exine of pollen grains. It is extremely resistant and can withstand extremes of temperature presumably as an adaptation to protect the male gametophyte. The exine is weak at few points where sporopollenin is missing. These are germ pores from where pollen germinates that is, pollen tube protrudes out during  germination.

Proteins are very versatile biomolecules performing different structural and functional roles. Proteins are also information molecules having amino acids joined together in a unique sequence which is decided by the sequence of nucleotides in nucleic acids DNA and RNA. Because different animals will have different sequence of nucleotides in DNA, the proteins synthesized in their body will also have different sequence of amino acids.

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.