DNA Function and Gene Expression Flashcards

This set of vocabulary flashcards covers the essential terms and concepts of DNA structure, replication, transcription, and translation as detailed in Modules 18 and 19.

Sugar-Phosphate Backbone

The structural framework formed on the outside of the DNA molecule.

Nucleotides

The building blocks of nucleic acids composed of Adenine ($A$), Thymine ($T$), Guanine ($G$), and Cytosine ($C$).

Hydrogen Bonds

The chemical connections that link complementary bases together in the DNA double helix.

Antiparallel DNA Strands

A characteristic of the DNA double helix where the two strands run in opposite directions.

Central Dogma of Molecular Biology

The fundamental framework describing the flow of genetic information: $DNA \rightarrow RNA \rightarrow Protein$.

DNA Replication

The process by which a cell creates a duplication of its DNA.

Transcription

The process where DNA is used as a template to synthesize RNA.

Translation

The process where RNA is used as a template to synthesize proteins.

Uracil ($U$)

The nucleobase that replaces Thymine ($T$) in RNA molecules.

Complementary Base Pairing

The specific rule where Adenine ($A$) pairs with Thymine ($T$) and Guanine ($G$) pairs with Cytosine ($C$) to maintain DNA stability.

Semiconservative Replication

A method of DNA replication where each new DNA molecule contains one original strand and one newly synthesized strand.

Helicase

The enzyme responsible for unzipping the DNA helix during the replication process.

DNA Polymerase

The enzyme that adds nucleotides to form new DNA strands during replication.

Nucleotide Composition Rule

The mathematical relationship in DNA where $A + C = G + T$.

RNA Polymerase

The enzyme that binds to a promoter to initiate the synthesis of an mRNA strand.

Initiation

The first stage of transcription where RNA polymerase binds to a promoter sequence.

Elongation

The stage of transcription during which the RNA strand grows longer.

Termination

The final stage of transcription where the process ends at a specific stop sequence.

Codon

A three-nucleotide sequence in mRNA that codes for a specific amino acid.

AUG

The start codon that codes for the amino acid Methionine.

Stop Codons

The specific mRNA sequences ($UAA$, $UAG$, and $UGA$) that signal the end of protein synthesis.

tRNA

The molecule that carries genetic code and brings specific amino acids to ribosomes for protein assembly.

Ribosomes

The cellular sites of protein synthesis composed of large and small subunits.

Wild Type

The standard, non-mutated version of an mRNA or protein sequence.

Frameshift Mutation

A mutation that shifts the reading frame of the mRNA, potentially altering the entire amino acid sequence or creating early stop codons.