Removal of the introns and joining of the exons in a defined order in a transcription unit is called
In some eukaryotes, genes consist of coding nucleotids sequences, which are separated from each other by blocks of non-coding sequences. The coding sequences here are called exons and non-coding sequences are introns. The primary transcript from a typical eukaryotic gene contains introns as well as exons. The introns are removed from this primary transcript by a process called RNA splicing.
During transcription, the DNA site at which RNA polymerase binds is called
During transcription, a DNA sequence is read by an RNA polymerase, which produces a complementary, antiparallel RNA strand called a primary transcript. Transcription proceeds in the following general steps: RNA polymerase, together with one or more general transcription factors, binds to promoter DNA.
The coding segment of DNA Is called in
The genetic code by which DNA stores the genetic information consists of "codons" of three nucleotides. The functional segments of DNA which code for the transfer of genetic information are called genes. A codon is defined by the initial nucleotide from which translation starts.
Some amino acids are coded by more than one codon hence, the code is
The genetic code is degenerate: Some amino acids are encoded by more than one codon, in as much as there are 64 possible base triplets and only 20 amino acids. In fact, 61 of the 64 possible triplets specify particular amino acids and 3 triplets (called stop codons) designate the termination of translation. Thus, for most amino acids, there is more than one codeword.
Out of 64 codons, the number of codons with GGG is
GGG code is present only 1 tym and the amino acid produced by GGG is glycine.
Control of gene expression takes place at the level of
Prokaryotic transcription and translation occur simultaneously in the cytoplasm, and regulation occurs at the transcriptional level. Eukaryotic gene expression is regulated during transcription and RNA processing, which take place in the nucleus, and during protein translation, which takes place in the cytoplasm.
The amino acid attached to the tRNA at its
One end of the tRNA matches the genetic code in a three-nucleotide sequence called the anticodon. On the other end of the tRNA is a covalent attachment to the amino acid that corresponds to the anticodon sequence. This covalent attachment to the tRNA 3' end is catalyzed by enzymes called aminoacyl tRNA synthetases.
The portion of DNA which contains information for an entire polypeptide is called
A cistron is an alternative term to a gene.The word cistron is used to emphasize that genes exhibit a specific behavior in a cis-trans test, distinct positions (or loci) within a genome are cistronic.
Which of the following steps in transcription is catalysed by RNA polymerase?
The correct option is Option D.
There is single DNA-dependent RNA polymerase that catalyses transcription of all types of RNA in bacteria. RNA polymerase binds to the promoter and initiates transcription (Initiation). It uses nucleoside triphosphates as substrate and polymerises in a template dependent fashion following the rule of complementarity. It somehow also facilitates opening of the helix and continues elongation. Only a short stretch of RNA remains bound to the enzyme. Once the polymerases reach the terminator region, the nascent RNA falls off, so also the RNA polymerase. This results in termination of transcription. The RNA polymerase is only capable of catalysing the process of elongation. It associates transiently with initiation-factor (σ) and termination-factor (ρ) to initiate and terminate the transcription respectively. Association with these factors alter the specificity of the RNA polymerase to either initiate or terminate.
So, the correct answer is 'All of the above'.
DNA elements, which can switch their positions, are called
A transposable element (TE or transposon) is a DNA sequence that can change its position within a genome, sometimes creating or reversing mutations and altering the cell's genetic identity and genome size.