Mol Bio: DNA

Double Helical Structure of DNA

The structure of DNA, first described by James Watson and Francis Crick

Rosalind Franklin

Who? difraction analysis provided crucial physical evidence that helped Watson and Crick determine the helical structure of DNA.

Johann Friedrich Miescher

Who discovered DNA while isolating WBC from discarded surgical bandages?

700 kD

size of nucleotides

Nucleosides

unphosphorylated sugar

Nucleotides

phosphorylated sugar

hydrolysis

Nucleotides can be converted to nucleosides by?

Hydroxyl group on the third carbon

Important for forming the phosphodiester bond

Phosphodiester Bond

The bond formed between the third carbon of one nucleotide's sugar and the fifth carbon of the next nucleotide’s sugar, forming the backbone of the DNA strand.

Nitrogen Bases

Planar carbon-nitrogen ring structures.

B-form

The standard, hydrated form of DNA, characterized by a right-handed double helix with 10.5 base pairs per turn.

A-form

Occurs when DNA is dehydrated, right-handed helices, with 11 base pairs per turn and a different helical structure (center of symmetry on the outside).

Z-form

A left-handed helix with 12 base pairs per turn, typically formed under torsional stress (e.g., during transcription).

Z-form

has altered sugar-base bond geometry

James Watson

Coined the term “molecular biology,”

James Watson

He was referring to the biology of DNA.

Molecular Techniques

Designed for the handling and analysis of the nucleic acids, DNA and RNA.

Protein analysis, carbohydrates and other molecular species

These analyses are typically part of clinical chemistry, not molecular biology, but molecular techniques are being incorporated into protein analysis.

Molecular Biology Laboratory

May be a separate entity or part of an existing molecular diagnostics or molecular pathology unit.

DNA (Deoxyribonucleic Acid)

A macromolecule made up of carbon, nitrogen, oxygen, phosphorus, and hydrogen atoms.

DNA (Deoxyribonucleic Acid)

A molecule found in the nucleus of cells that stores genetic information, crucial for biological functions and inheritance.