DNA & RNA

Genes

Fundamental units of heredity, located on chromosomes.

Chromosomes

Structures composed of DNA tightly coiled around proteins (histones), forming chromatin when uncondensed.

DNA (Deoxyribonucleic Acid)

The primary genetic material in most organisms, responsible for long-term storage of genetic information.

Nucleotide

A repeating monomer unit of DNA comprised of a five-carbon sugar, a phosphate group, and a nitrogenous base.

Deoxyribose

A five-carbon sugar that makes up the backbone of DNA, lacking a hydroxyl group at the 2' carbon.

Purines

Nitrogenous bases with a double-ring structure; includes adenine (A) and guanine (G).

Pyrimidines

Nitrogenous bases with a single-ring structure; includes cytosine (C) and thymine (T).

Antiparallel Strands

Describes the orientation of the two strands of DNA; one runs 5' to 3' and the other runs 3' to 5'.

Hydrogen Bonds

Weak bonds that hold the nitrogenous bases together in the DNA structure; A pairs with T, C pairs with G.

Central Dogma of Molecular Biology

The process by which DNA is transcribed to RNA, which is translated to protein.

mRNA (Messenger RNA)

RNA that carries genetic information from DNA in the nucleus to ribosomes for protein synthesis.

tRNA (Transfer RNA)

RNA that translates the mRNA sequence into amino acids during protein synthesis.

rRNA (Ribosomal RNA)

RNA that is a major component of ribosomes, responsible for protein synthesis.

James Watson and Francis Crick

Scientists who proposed the double-helix structure of DNA in 1953.

Chargaff's Rules

Principle that states A=T and C=G in DNA base pairing.

Rosalind Franklin

Scientist whose X-ray diffraction data contributed to the discovery of the DNA structure.