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2021-05-14

What causes DNA to unzip?

What causes DNA to unzip?

The breaking of the hydrogen bonds due to the force relieves the torsional stress stored in a double helix. As a result, the nucleotide strands rotate more freely about the axis of a helix and start unwinding. The DNA unwinding occurs simultaneously with the DNA unzipping.

Where does DNA unzipping happen?

However, DNA does not unzip entirely. It unzips in a small area called a replication fork, which then moves down the entire length of the molecule. Let’s look at the details: An enzyme called DNA gyrase makes a nick in the double helix and each side separates.

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How does DNA separate into two strands?

First, a so-called initiator protein unwinds a short stretch of the DNA double helix. Then, a protein known as helicase attaches to and breaks apart the hydrogen bonds between the bases on the DNA strands, thereby pulling apart the two strands.

What are the two DNA components?

DNA has three types of chemical component: phosphate, a sugar called deoxyribose, and four nitrogenous bases—adenine, guanine, cytosine, and thymine. Two of the bases, adenine and guanine, have a double-ring structure characteristic of a type of chemical called a purine.

What is found in the sequence makes it easier for the DNA to separate?

The origin is about 245 base pairs long and has mostly A/T base pairs (which are held together by fewer hydrogen bonds than G/C base pairs), making the DNA strands easier to separate.

Which strand of DNA would be more stable less likely to separate into two strands )?

From the base-pairing diagram, we can see that the G-C pair has 3 hydrogen bonds, while the A-T pair has only 2. Therefore, the G-C pairing is more stable than the A-T pairing. Thus, strands with more G-C content have more hydrogen bonding, are more stable, and have a greater resistance to denaturation.

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What holds DNA apart?

Chapter 16 review

Question Answer
What is the job of helicase? It untwists and separates the strands.
What holds the DNA strands apart? Single strand binding proteins
What synthesizes the RNA primer? DNA primase
What adds DNA nucleotides to new strands? DNA polymerases

What enzyme holds DNA apart?

DNA Helicase

What enzyme is responsible for DNA repair?

DNA ligase

What is types of DNA?

There are two types of DNA in the cell – autosomal DNA and mitochondrial DNA. Autosomal DNA (also called nuclear DNA) is packaged into 22 paired chromosomes. In each pair of autosomes, one was inherited from the mother and one was inherited from the father.

What DNA is present in humans?

The information in DNA is stored as a code made up of four chemical bases: adenine (A), guanine (G), cytosine (C), and thymine (T). Human DNA consists of about 3 billion bases, and more than 99 percent of those bases are the same in all people.

Why is B form DNA most stable?

It is known that the stability of the double helical structure of B-DNA is supplied by the hydrogen bonds as proposed by Watson and Crick3 and by the stacking interactions. However, the relative importance of both stabilizing interactions as well as how they interfere with each other is largely unknown.

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Why is it important for DNA to be stable?

The genome consists of DNA. No cell can function without the proteins that it requires, so it cannot function without its genes, its DNA. Every cell must begin with a very accurate copy of its parent’s or parents’ DNA. So it is important for the DNA to be stable, to resist change, otherwise inaccuracies will appear.

Why does DNA denature into two strands at very high pH?

At high pH, then, the solution is rich in hydroxide ions, and these negatively-charged ions can pull hydrogen ions off of molecules like the base pairs in DNA. This process disrupts the hydrogen bonding that holds the two DNA strands together, causing them to separate.

What is the pH of TRIzol?

Table 2.

Purity (A260/280)
Low (<1.7)
Concentration (ng/μL) High (>25) CTAB, pH 5 TRIzol, pH 5

Is DNA acidic or basic?

You’re right: DNA is built of both acidic and basic components. The acidic component of DNA is its phosphate group, and the basic component of DNA is its nitrogenous base.

Is RNA acidic or basic?

Ribonucleic acid (RNA) is a polymeric molecule essential in various biological roles in coding, decoding, regulation and expression of genes. RNA and DNA are nucleic acids.