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2021-05-14

Why is the double helix structure of DNA important?

Why is the double helix structure of DNA important?

The double-helix shape allows for DNA replication and protein synthesis to occur. In these processes, the twisted DNA unwinds and opens to allow a copy of the DNA to be made. In DNA replication, the double helix unwinds and each separated strand is used to synthesize a new strand.

What is the advantage of the double stranded aspect of the DNA?

What is the advantage of the double stranded aspect of the DNA molecule? Allow for exact replication. Each parent strand dictates what is to be on each new daughter strand.

What did the structure of DNA double helix suggest?

What did the structure of DNA’s double helix suggest about DNA’s properties? The structure of DNA suggested that the order of bases contains information. Because A is always paired with T and G with C, the order of bases on one strand determines the order on the other strand.

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What does the double helix tell us about DNA?

The double helix describes the appearance of double-stranded DNA, which is composed of two linear strands that run opposite to each other, or anti-parallel, and twist together. Each DNA strand within the double helix is a long, linear molecule made of smaller units called nucleotides that form a chain.

Is DNA really a double helix?

DNA is a double-stranded helix, with the two strands connected by hydrogen bonds. A bases are always paired with Ts, and Cs are always paired with Gs, which is consistent with and accounts for Chargaff’s rule.

Why does DNA not look like a double helix?

Under a microscope, the familiar double-helix molecule of DNA can be seen. Because it is so thin, DNA cannot be seen by the naked eye unless its strands are released from the nuclei of the cells and allowed to clump together.

Does RNA have a double helix?

RNA, like DNA, can form double helices held together by the pairing of complementary bases, and such helices are ubiquitous in functional RNAs.

Is RNA a single or double helix?

Unlike double-stranded DNA, RNA is a single-stranded molecule in many of its biological roles and consists of much shorter chains of nucleotides. However, a single RNA molecule can, by complementary base pairing, form intrastrand double helixes, as in tRNA.

Does RNA have helix structure?

Although usually single-stranded, some RNA sequences have the ability to form a double helix, much like DNA. Gehring said identifying the double-helical RNA will have interesting applications for research in biological nanomaterials and supramolecular chemistry.

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Why DNA is more stable than RNA?

Due to its deoxyribose sugar, which contains one less oxygen-containing hydroxyl group, DNA is a more stable molecule than RNA, which is useful for a molecule which has the task of keeping genetic information safe. RNA, containing a ribose sugar, is more reactive than DNA and is not stable in alkaline conditions.

What makes DNA more stable?

The main bonding in DNA which renders the double helix structure so stable is that of hydrogen bonds. As well as this there are hydrogen bonds between the bases and surrounding water molecules, and this combined with the even stronger phosphodiester bonds in the sugar phosphate backbone make DNA very stable.

Where is RNA polymerase II found?

nucleus

What is the function of polymerase II?

Eukaryotic RNA polymerase II (pol II) is a 12-subunit DNA-dependent RNA polymerase that is responsible for transcribing nuclear genes encoding messenger RNAs and several small nuclear RNAs (1).

What happens to RNA polymerase II after it?

What happens to RNA polymerase II after it has completed transcription of a gene? The enzyme is free to transcribe other genes in the cell. RNA polymerase releases the completed RNA and detaches from the DNA.

How does RNA polymerase II work?

RNA polymerase II (RNAP II and Pol II) is a multiprotein complex that transcribes DNA into precursors of messenger RNA (mRNA) and most small nuclear RNA (snRNA) and microRNA. A 550 kDa complex of 12 subunits, RNAP II is the most studied type of RNA polymerase.

What does each RNA polymerase do?

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.

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What is the significance of the carboxyl terminal domain of RNA polymerase II?

The carboxy-terminal domain is also the binding site for spliceosome factors that are part of RNA splicing. These allow for the splicing and removal of introns (in the form of a lariat structure) during RNA transcription.

Is RNA polymerase a DNA binding protein?

Only RNA polymerase that has the T4 gene 33 protein (gp33) bound to it is subject to enhancement by the three DNA replication proteins. coli promoter recognition protein, sigma 70, for binding to the E.

Can RNA polymerase unwind DNA?

In any case, upon binding, the RNA pol “core enzyme” binds to another subunit called the sigma subunit to form a holoezyme capable of unwinding the DNA double helix in order to facilitate access to the gene.

How does RNA polymerase attach to DNA?

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 effects can a DNA binding protein have on RNA polymerase activity?

Binding of regulatory proteins to an enhancer sequence causes a shift in chromatin structure that either promotes or inhibits RNA polymerase and transcription factor binding. A more open chromatin structure is associated with active gene transcription.