Question

A sequential expression of a set of human genes occurs when a steroid molecule binds to the
A. Transfer RNA
B. Messenger RNA
C. DNA sequence
D. Ribosome

Answer 1

A sequential expression refers to a series of functions initiated by a molecule leading the events in a procedural way. The human genome consists of functional segments called cistron. The steroid molecules are generally sex hormone that binds to these functional regions and causes a cascade or sequential expression.

Complete answer:
The human genome is made up of double-stranded DNA or deoxyribonucleic acid molecules enclosed in the nucleus of the cell. The DNA consists of various segments that are functional and results in the production of some important proteins or enzymes. These regions are termed as genes or cistrons.
-During the process of transcription, the mRNA segment or messenger RNA segment is made from encoding the bases present in the cistron region of DNA sequences. This mRNA undergoes some modifications to become functional and ready to be decoded by translation machinery. The functional mRNA leaves the nucleus and enters the cytoplasm where the translation machinery consisting of tRNA or transfer RNA and ribosomes translates it.
-The translation is a decoding procedure that results in the formation of amino acids. These amino acids chain up or form polymers called proteins. These proteins further are transported to other cell places or target sites where they act in various metabolic functions. These metabolic functions result in either differentiation mechanisms or production mechanisms. So this process occurs in a specific procedural way.
-The steroid molecules in the body are generally represented by steroid hormones specifically sex hormones. The hormones are chemical messengers that carry some signals for the functional regions of DNA sequences to get activated. The activation of the DNA sequence results in the initiation of the sequential expression process described above.
So, option C is the correct answer.

Note: The effect introduced by the synthesis of a particular protein on a certain function is termed as protein expression. This is possible only by the translation of cistron or functional regions of DNA. But the majority of DNA consists of non-functional sequences. The function of these sequences is unknown and not completely understood. But these are related to evolutionary functions.