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2021-05-14

Where does a repressor bind?

Where does a repressor bind?

promoter region

What does the repressor bind to on the operon?

The lac repressor protein binds to the operator and blocks RNA polymerase from binding to the promoter and transcribing the operon. The promoter is the binding site for RNA polymerase, the enzyme that performs transcription.

Does the repressor bind to the operator?

The repressor binds to the operator gene and prevents it from initiating the synthesis of the protein called for by the operon. The presence or absence of certain repressor molecules determines whether the operon is off or on.

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Where do repressors bind in eukaryotes?

Transcriptional repressors can bind to promoter or enhancer regions and block transcription. Like the transcriptional activators, repressors respond to external stimuli to prevent the binding of activating transcription factors.

What three parts make up an operon?

An operon is made up of 3 basic DNA components:

  • Promoter – a nucleotide sequence that enables a gene to be transcribed.
  • Operator – a segment of DNA to which a repressor binds.
  • Structural genes – the genes that are co-regulated by the operon.

What are two mechanisms of protein regulation in eukaryotic cells?

Two mechanism of protein regulation are identified in part (b): “feedback inhibition and allosteric regulation.” This earned 2 points: 1 point for each mechanism.

What is the function of a ribosome in protein synthesis?

Within the ribosome, the rRNA molecules direct the catalytic steps of protein synthesis — the stitching together of amino acids to make a protein molecule. In fact, rRNA is sometimes called a ribozyme or catalytic RNA to reflect this function.

What do Spliceosomes do in protein synthesis?

Explain the role of Spliceosomes in protein synthesis. Spliceosomes are used by eukaryotic cells in mRNA manipulation. Before the mRNA is actually read, spliceosomes cut out introns and ligate exons. This results in a more efficient translation.

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What is the role of ATP in protein synthesis?

ATP powers the synthesis of proteins, nucleic acids and all other building blocks that make up organisms. In addition, ATP fuels transport of molecules across the membrane, cell movement and cell division [1]

What are the two components of Spliceosomes?

Each spliceosome is composed of five small nuclear RNAs (snRNA) and a range of associated protein factors. When these small RNAs are combined with the protein factors, they make RNA-protein complexes called snRNPs (small nuclear ribonucleoproteins, pronounced “snurps”).

Are snRNPs Spliceosomes?

snRNPs (pronounced “snurps”), or small nuclear ribonucleoproteins, are RNA-protein complexes that combine with unmodified pre-mRNA and various other proteins to form a spliceosome, a large RNA-protein molecular complex upon which splicing of pre-mRNA occurs.

Is snRNA a prokaryote?

Small nuclear RNA (snRNA) is a class of small RNA molecules that are found within the splicing speckles and Cajal bodies of the cell nucleus in eukaryotic cells. The length of an average snRNA is approximately 150 nucleotides.

What is the purpose of snRNPs?

Splicing and Ribozymes. Different snRNPs are found in eukaryotic cells which function in removing introns from primary RNA transcripts. The association of small RNAs, nuclear proteins, and the introns that they attach to is referred to as a spliceosome.

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Why are introns removed during splicing?

During splicing, introns (non-coding regions) are removed and exons (coding regions) are joined together. For those eukaryotic genes that contain introns, splicing is usually required in order to create an mRNA molecule that can be translated into protein.

What are the steps of mRNA processing?

The three most important steps of pre-mRNA processing are the addition of stabilizing and signaling factors at the 5′ and 3′ ends of the molecule, and the removal of intervening sequences that do not specify the appropriate amino acids. In rare cases, the mRNA transcript can be “edited” after it is transcribed.

What are 3 steps of translation?

Translation of an mRNA molecule by the ribosome occurs in three stages: initiation, elongation, and termination.

What is the order for protein synthesis?

Protein synthesis is the process in which cells make proteins. It occurs in two stages: transcription and translation. Transcription is the transfer of genetic instructions in DNA to mRNA in the nucleus. It includes three steps: initiation, elongation, and termination