AS91159 Gene Expression Glossary

Vocabulary flashcards covering key terms involved in gene expression for AS91159 Biology.

Anticodon

Three consecutive bases on tRNA that are complementary to an mRNA codon.

Codon

Three consecutive bases on mRNA that specify an amino acid or a stop signal.

Deletion mutation

A mutation where one or more bases are removed from DNA, producing a frameshift.

DNA

Deoxyribonucleic acid; double-stranded helix in chromosomes where A pairs with T and C pairs with G.

Deoxyribose sugar

Five-carbon sugar component of DNA nucleotides.

Enzyme

Folded protein that acts as a biological catalyst, speeding up chemical reactions.

Frameshift

Shift in the reading frame that alters how the ribosome reads subsequent codons.

Gene

Segment of DNA that codes for a specific protein or trait.

Gene expression

Conversion of DNA instructions into a functional protein via transcription, translation, and folding.

Genotype

The genetic makeup of an organism for a particular feature.

Insertion mutation

Mutation where extra base(s) are added to DNA, producing a frameshift.

Metabolic pathway

Series of enzyme-controlled reactions where the product of one reaction becomes the substrate for the next.

Missense mutation

Single base change that leads to a different amino acid; may alter protein shape or function.

mRNA

Messenger RNA made during transcription; carries codons from nucleus to ribosome.

Mutagen

Environmental factor that causes mutations, e.g., X-rays, chemicals.

Mutation

Permanent change in the DNA base sequence.

Non-sense mutation

Base change that creates a premature stop codon, severely affecting the protein.

Peptide bond

Covalent bond linking two amino acids during translation.

Phenotype

Observable physical expression of a trait.

Point mutation

Change in a single base or a few bases in DNA.

Protein

Polymer of many amino acids folded into a functional form; includes enzymes.

Redundancy

Characteristic of the genetic code where multiple codons specify the same amino acid.

RNA

Ribonucleic acid; single-stranded with ribose sugar; A pairs with U and C pairs with G; types include mRNA, tRNA, rRNA.

Same-sense mutation

Base change that still codes for the same amino acid due to redundancy in the genetic code.

Silent mutation

Mutation that is neither advantageous nor harmful and remains in the population.

Start codon

AUG sequence on mRNA that signals the beginning of translation.

Stop codon

UAA, UAG, or UGA sequences on mRNA that signal termination of translation.

Substitution mutation

Mutation where one base is replaced by another in DNA.

Transcription

Process in the nucleus where DNA is used as a template to make mRNA; catalyzed by RNA polymerase.

Translation

Process in the cytoplasm where ribosomes use mRNA codons to assemble a polypeptide chain.

Triplet

Three consecutive bases on DNA.

tRNA

Transfer RNA that carries a specific amino acid to the ribosome and contains an anticodon complementary to an mRNA codon.