PCR - DNA Stability

These flashcards cover key concepts regarding the structure and stability of DNA as discussed in the lecture.

What is the structural form of DNA?

DNA is double stranded with a helical structure.

What makes up the backbone of DNA?

The backbone of DNA consists of linked sugar phosphates.

What is the rise per base pair in DNA?

The rise per base pair is approximately 0.34 nm.

At what angle does DNA rotate per base?

DNA rotates 36 degrees per base.

What wavelengths are associated with the maximal light absorption of nucleic acids?

Nucleic acids absorb maximally at 260 nm.

What is the Hypochromic Effect in DNA?

In double-stranded DNA, tightly stacked bases result in decreased UV light absorption.

What happens to absorbance during DNA denaturation?

Absorbance increases as double-stranded DNA is converted to single-stranded DNA.

What is TM in the context of nucleic acids?

TM is the melting temperature, where DNA is 50% double-stranded and 50% single-stranded.

How does GC content affect the stability of DNA?

Higher GC content increases stability due to more hydrogen bonds and stronger stacking interactions.

What role does salt play in DNA stability?

Salt shields the negative charges on the sugar-phosphate backbone, reducing electrostatic repulsion and stabilizing DNA.

What is the cooperative nature of DNA denaturation?

Denaturation is cooperative; as more bases separate, the likelihood of further separation increases.

How are the forces stabilizing DNA described?

Base pairing and electrostatic repulsion of sugar-phosphate backbones affect DNA stability.

What can happen if denatured DNA is cooled rapidly below its TM?

It may aggregate and partially base-pair, rather than renature completely.

What is the effect of Mg2+ on DNA stability?

Mg2+ neutralizes negative charges on the DNA backbone, increasing stability.