Molecular Biology: DNA, Gene Expression, and Mutations

A set of vocabulary flashcards covering DNA structure, replication, protein synthesis, and genetic mutations.

Nucleotide

The basic building block of DNA, consisting of a phosphate group, a deoxyribose sugar, and a nitrogenous base.

Chargaff’s rule

The principle stating that in a DNA molecule, the amount of adenine equals thymine ($A = T$) and the amount of guanine equals cytosine ($G = C$).

Relationship of Genes, DNA, and Chromosomes

Genes are specific segments of DNA that contain instructions for proteins, and DNA is packaged into long, thread-like structures called chromosomes.

DNA replication

The process of copying a DNA molecule to ensure the transmission and conservation of the genetic code during cell division.

DNA (Deoxyribonucleic Acid)

A double-stranded molecule containing deoxyribose sugar and the nitrogenous base thymine, functioning in long-term genetic storage.

RNA (Ribonucleic Acid)

A typically single-stranded molecule containing ribose sugar and the nitrogenous base uracil, functioning in protein synthesis.

Codon

A three-nucleotide sequence on mRNA that specifies a particular amino acid or termination signal during translation.

Anticodon

A three-nucleotide sequence on a tRNA molecule that is complementary to a specific codon on mRNA.

Transcription

The process of synthesizing mRNA from a DNA template to carry genetic information out of the nucleus.

Translation

The process in which a ribosome decodes mRNA to assemble a specific sequence of amino acids into a polypeptide chain.

Gene Expression

The combined process of transcription and translation where information encoded in DNA is used to create functional proteins.

Silent Mutation

A change in the DNA sequence that does not result in a change to the amino acid sequence of the encoded protein.

Point (Missense) Mutation

A mutation where a single nucleotide change results in the substitution of one amino acid for another in the final protein.

Frameshift Mutation

A mutation involving the insertion or deletion of nucleotides that shifts the reading frame of the genetic message, typically changing multiple amino acids.