Molecular Biology: DNA Structure and Function

These flashcards cover key vocabulary and concepts related to the molecular biology of DNA, including its structure, function, and historical discoveries.

Nucleotide

The basic structural unit of nucleic acids, consisting of a nitrogenous base, a sugar, and one or more phosphate groups.

Polynucleotide

A polymer consisting of many nucleotide monomers in a chain; examples include DNA and RNA.

Phosphodiester bond

A type of bond that links nucleotides together in a polynucleotide, formed between the phosphate group of one nucleotide and the 3' hydroxyl group of another.

Supercoiling

A structural feature of circular DNA, where the DNA twists and coils to manage topological strain.

Watson and Crick model

The double helix structure of DNA proposed by James Watson and Francis Crick, characterized by two antiparallel strands wound around each other.

Chargaff's rules

In DNA, the amount of adenine is equal to thymine, and the amount of guanine is equal to cytosine.

A-DNA

A right-handed double helical form of DNA that is shorter and thicker than B-DNA.

Z-DNA

A left-handed double helical form of DNA that has a zigzag appearance.

Base stacking

The interactions between adjacent bases in a polynucleotide that contribute to the stability of the DNA structure.

Tautomer

A molecule that has migrated protons leading to isomeric forms, which can affect the accuracy of DNA replication.

Transformation principle

The substance responsible for genetic transformation in bacteria, identified as DNA through Griffith's and Avery's experiments.

Topoisomerase

An enzyme that alters the supercoiling of DNA by cutting the DNA strands to introduce or remove supercoils.

DNA replication

The process by which a cell duplicates its DNA, ensuring that each new cell receives an accurate copy.

Antiparallel

Referring to the opposite orientation of the two strands of DNA in a double helix; one strand runs 5' to 3' and the other runs 3' to 5'.

Deoxyribonucleic acid (DNA)

The molecule that carries genetic information in all living organisms and many viruses.