Molecular Genetics

RNA polymerase 1 (also known as Pol I) is, in higher eukaryotes, the polymerase that only transcribes ribosomal RNA (but not 5S rRNA, which is synthesized by RNA polymerase III), a type of RNA that accounts for over 50% of the total RNA synthesized in a cell. Pol I is a 590 kDa enzyme that consists of 14 protein subunits (polypeptides). Twelve of its subunits have identical or related counterparts in RNA polymerase II (Pol II) and RNA polymerase III (Pol III). The other two subunits are related to Pol II initiation factors and have structural homologues in Pol III. Ribosomal DNA transcription is confined to the nucleolus, where about 400 copies of the 42.9-kb rDNA gene are present, arranged as tandem repeats in nucleolus organizer regions. Each copy contains a 13.3 kb sequence encoding the 18S, the 5.8S, and the 28S RNA molecules, interlaced with two internal transcribed spacers, ITS1 and ITS2, and flanked upstream by a 5' external transcribed spacer and a downstream 3' external transcribed spacer. Because of the simplicity of Pol I transcription, it is the fastest-acting polymerase and contributes up to 60% of cellular transcription levels in exponentially growing cells.

Respiratory quotient (RQ) is the ratio of the volume of carbon dioxide released to the volume of oxygen taken in respiration in the given period of time at standard temperature and pressure. 

Inactivation of RNA by using another RNA is called RNA interference(RNAi). It is used in pest control in tomato plant. It is a cellular defence method. It is applicable to eukaryotes only.

So, the correct option is ‘Eukaryotes’.

A DNA segment that contributes to phenotype/function is called gene. In prokaryotes, the predominant site for control of gene expression is at Transcription level, where as in eukaryotes, control of gene expression occurs at transcription level, processing level, transport of mRNA, translation level.

So, the correct option is ‘Transcription intiations’.

In eukaryotes, the translation process begins at the start codon AUG, which codes for the amino acid methionine.

Promoter is a DNA segment that serves to initiate transcription of a particular gene. They are present upstream near the transcription start sites of genes. Regulator gene regulates the expression of structural genes by its protein product that are mostly transcription factors. These transcription factors bind to the operator region which is located just upstream the binding site of the RNA polymerase and hence, prevent the binding and transcription. Operator is a DNA sequence present between the promoter region and the first coding gene. This operator region serves as repressor protein binding site. The gene that codes for any RNA / protein product which do not serve as regulatory protein are known as structural genes. The lac Z lac Y and lac A genes in lac operon are the structural genes. Option B is the correct answer.

The promoter is a DNA segment that serves to initiate transcription of a particular gene. They are present upstream near the transcription start sites of genes. Regulator gene regulates the expression of structural genes by its protein product that is mostly transcription factors, also termed as the repressor. The operator is a DNA sequence present between the promoter region and the first coding gene. This operator region serves as a repressor protein binding site. The repressor binds to operator region which is located just upstream the binding site of the RNA polymerase and hence, prevent the binding and transcription; this makes option C incorrect. Regulator gene serves to regulate the expression of structural genes via repressor; it does not provide the binding site for RNA polymerase; option A is wrong. The inducer is a molecule that binds to repressor to prevent its binding to operator region and thereby, facilitates gene expression; option B is incorrect.

In genetics, a promoter is a region of DNA that initiates transcription of a particular gene. Promoters are located near the transcription start sites of genes, on the same strand and upstream on the DNA (towards the 5' region of the sense strand).

The gene that codes for any RNA/protein product which does not serve as regulatory protein is known as structural genes. The operator is a DNA sequence present between the promoter region and the first coding gene. The operator region serves as the repressor protein binding site. The promoter is a DNA segment that serves to initiate transcription of a particular gene. They are present upstream near the transcription start sites of genes in between the operator and structural gene. The regulatory gene regulates the expression of structural genes by its protein products that are mostly transcription factors. It is not the part of an operon, which means that it is present upstream or downstream the structural genes but not in between; the Regulatory gene is present upstream the operator gene. Thus, the correct answer option D.

In eukaryotic cells, the DNA is contained within the nucleus, which is where the process of transcription (DNA to RNA) occurs. Translation then takes place in the cytoplasm.

During the processing of eukaryotic hnRNA, tailing (polyadenylation) involves the addition of a long chain of adenylate residues (poly-A tail) to the 3' end of the transcript to protect it and aid in export.

In prokaryotes, the peptidyl transferase activity, which catalyzes the formation of peptide bonds during translation, is an intrinsic function of the 23S rRNA component of the 50S ribosomal subunit.

Split genes are genes that contain introns, which are transcribed into hnRNA (pre-mRNA) and subsequently removed during RNA splicing to produce mature mRNA.

In eukaryotes, RNA polymerase III is responsible for transcribing small RNAs, including tRNA and 5S rRNA. Therefore, its removal would specifically affect the transcription of tRNA.