Which direction is the RNA polymerase moving in Model 1?

During elongation, RNA polymerase "walks" along one strand of DNA, known as the template strand, in the 3' to 5' direction. For each nucleotide in the template, RNA polymerase adds a matching (complementary) RNA nucleotide to the 3' end of the RNA strand.

Just so, what protein does the regulatory gene in Model 1 produce?

The regulatory gene lacI produces an mRNA that produces a Lac repressor protein, which can bind to the operator of the lac operon. In some texts, the lacI regulatory gene is called the lacI regulator gene. Regulatory genes are not necessarily close to the operons they affect.

Additionally, how does the change identified in Part A allow transcription of the genes in the operon to occur? The repressor protein binds to the operator site. The repressor protein changes shape. How does the change identified in part A allow transcription of the genes in operon to occur? The repressor protein no longer binds to the operator and is no longer blocking RNA polymerase, so transcription can occur.

Regarding this, which way does RNA move?

RNA polymerase synthesizes an RNA transcript complementary to the DNA template strand in the 5' to 3' direction. It moves forward along the template strand in the 3' to 5' direction, opening the DNA double helix as it goes.

How is gene expression controlled in prokaryotes quizlet?

Transcription, translation or post-translation. Negative control occurs when a regulatory protein prevents transcription. Positive control occurs when a regulatory protein increases the transcription rate.

37 Related Question Answers Found

Is mRNA a protein?

Messenger RNA (mRNA) is a large family of RNA molecules that convey genetic information from DNA to the ribosome, where they specify the amino acid sequence of the protein products of gene expression.

Can the protein produced by the regulatory gene?

The promoter. c. Can the protein produced by the regulatory gene bind to the operon itself? No, the activator protein must bind to a ligand before it can bind to the promoter.

Why are operons in prokaryotes?

Bacterial Operons Are Coregulated Gene Clusters

In addition to being physically close in the genome, these genes are regulated such that they are all turned on or off together. Grouping related genes under a common control mechanism allows bacteria to rapidly adapt to changes in the environment.

In what direction is the template strand read?

During transcription, the RNA polymerase read the template DNA strand in the 3′→5′ direction, but the mRNA is formed in the 5′ to 3′ direction. The mRNA is single-stranded and therefore only contains three possible reading frames, of which only one is translated.

What proteins help to direct the RNA polymerase to the right location?

Promoters are sequences of DNA that direct the RNA polymerase to the proper initiation site for transcription. Promoter sites can be identified and characterized by a combination of techniques. One powerful technique for characterizing these and other protein-binding sites on DNA is called footprinting (Figure 28.3).

Where do activator proteins bind?

Activator proteins bind to regulatory sites on DNA nearby to promoter regions that act as on/off switches. This binding facilitates RNA polymerase activity and transcription of nearby genes.

How does RNA polymerase work?

RNA polymerase is the main transcription enzyme. Transcription begins when RNA polymerase binds to a promoter sequence near the beginning of a gene (directly or through helper proteins). RNA polymerase uses one of the DNA strands (the template strand) as a template to make a new, complementary RNA molecule.

What is the repressor for trp operon?

Turning the operon "on" and "off"

This stretch of DNA is recognized by a regulatory protein known as the trp repressor. When the repressor binds to the DNA of the operator, it keeps the operon from being transcribed by physically getting in the way of RNA polymerase, the transcription enzyme.

What is the end product of transcription?

The end product of transcription is an RNA molecule. Hence, copying the information of genes in the genome into an RNA occurs during the transcription. The three main types of RNA produced by transcription are mRNA, tRNA, and rRNA.

Does it matter which side of the separated DNA is used for transcription?

Does it matter which of the separated DNA chains is used for transcription? Yes - along the way Uracil would replace Thymine in some scenarios which could possibly change the overall strand of amino acids.

What are the three stages of transcription?

Transcription occurs in the three steps—initiation, elongation, and termination—all shown here.

Step 1: Initiation. Initiation is the beginning of transcription.
Step 2: Elongation. Elongation is the addition of nucleotides to the mRNA strand.
Step 3: Termination.

How is mRNA synthesized and what message does it carry?

The message in your DNA of who you are and how your body works is carried out by cells through gene expression. In most cases this means synthesizing a specific protein to do a specific job. First, mRNA is transcribed from the DNA code. Then, the mRNA sequence is translated into a polypeptide sequence.

What is the role of RNA polymerase during transcription?

RNA polymerase (green) synthesizes RNA by following a strand of DNA. RNA polymerase is an enzyme that is responsible for copying a DNA sequence into an RNA sequence, duyring the process of transcription. RNA polymerases have been found in all species, but the number and composition of these proteins vary across taxa.

What is gene expression and what are the two stages?

The process of gene expression involves two main stages: Transcription. Translation. Transcription. The production of messenger RNA (mRNA) by the enzyme RNA polymerase, and the processing of the resulting mRNA molecule.

What is the mRNA complementary codon?

The codon is the three nucleotide sequence in the mRNA that indicates which amino acid should be incorporated in the growing polypeptide chain. The anticodon is the complementary three nucleotide sequence in the appropriate tRNA. The sequence signals which AUG acts as the translation start in mRNA.

What is the product of transcription?

The product of transcription is RNA, which can be encountered in the form mRNA, tRNA or rRNA while the product of translation is a polypeptide amino acid chain, which forms a protein. Transcription occurs in the nucleus in eukaryotic organisms, while translation occurs in the cytoplasm and endoplasmic reticulum.

What are the two types of operons?

Operons are of two types, inducible and repressible. ADVERTISEMENTS: Inducible Operon System – Lac Operon (Fig 6.34): An inducible operon system is a regulated unit of genetic material which is switched on in response to the presence of a chemical.