Gene Expression and Regulation – Bio 111 Chapter 7

Vocabulary flashcards covering key terms from the Gene Expression study guide.

DNA (Deoxyribonucleic Acid)

Double-stranded nucleic acid polymer of deoxyribose nucleotides that stores hereditary information.

Double Helix

Twisted-ladder shape formed by two complementary strands of DNA.

RNA (Ribonucleic Acid)

Single-stranded nucleic acid of ribose nucleotides involved in gene expression.

Nucleotide

Monomer of nucleic acids composed of a sugar, phosphate, and nitrogenous base.

Amino Acid

Monomer building block of proteins.

Gene

Sequence of DNA on a chromosome that encodes an RNA or protein product.

Chromosome

Structure of 50 % DNA and 50 % protein that carries many genes.

Genome

Complete genetic complement of an organism; all chromosomes and genes together.

Gene Expression

Use of gene information to synthesize a functional product; includes transcription and translation.

5′ End

End of a nucleic acid strand with a free phosphate on the fifth carbon of the sugar.

3′ End

End of a nucleic acid strand with a free hydroxyl on the third carbon of the sugar.

Transcription

Synthesis of RNA from a DNA template by RNA polymerase.

Translation

Process by which ribosomes read mRNA codons to assemble an amino-acid chain.

Template Strand

DNA strand read by RNA polymerase to build complementary RNA.

Non-template (Coding) Strand

DNA strand with the same sequence as mRNA except for thymine instead of uracil.

Promoter

DNA sequence where RNA polymerase and transcription factors bind to start transcription.

Termination Sequence

DNA region signaling RNA polymerase to stop transcription.

Transcription Factor

Protein that binds DNA to regulate the initiation of transcription.

RNA Polymerase

Enzyme that builds RNA using a DNA template.

5′ Cap

Modified guanine added to the 5′ end of eukaryotic mRNA that protects the transcript and aids ribosome binding and export.

Poly-A Tail

Long chain of adenines added to the 3′ end of eukaryotic mRNA to stabilize and regulate export.

Intron

Non-coding region removed from pre-mRNA during splicing.

Exon

Coding region retained in mature mRNA after splicing.

mRNA (Messenger RNA)

RNA that carries genetic information from DNA to the ribosome.

tRNA (Transfer RNA)

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

rRNA (Ribosomal RNA)

RNA component of the ribosome that, with proteins, forms the site of translation.

Ribosome

Ribonucleoprotein complex composed of rRNA and proteins that catalyzes protein synthesis.

Codon

Three-nucleotide sequence in mRNA specifying an amino acid or stop signal.

Anticodon

Three-nucleotide sequence in tRNA complementary to an mRNA codon.

Reading Frame

Grouping of mRNA bases into consecutive, non-overlapping codons.

Genetic Code

Set of 64 mRNA codons that designate the 20 amino acids plus start and stop signals.

Wobble

Flexible base pairing at the third position of a codon allowing one tRNA to recognize multiple codons.

Start Codon

AUG; signals the beginning of translation and encodes methionine.

Stop Codon

UAA, UAG, or UGA; signals termination of translation.

Leader Sequence

5′ untranslated region of mRNA that influences translation efficiency and stability.

Release Factor

Protein that binds a stop codon in the ribosome and frees the completed polypeptide.

Rough Endoplasmic Reticulum

Organelle studded with ribosomes where many secretory and membrane proteins are translated.

Operon

Cluster of bacterial genes plus promoter and operator transcribed together as one mRNA.

Epigenetics

Heritable changes in gene expression not involving DNA-sequence alteration, e.g., chromatin packing and methylation.

Chromatin Packing

Degree of DNA compaction; euchromatin is open and active, heterochromatin is closed and repressed.

DNA Methylation

Addition of methyl groups to DNA bases that generally silences gene expression.

Alternative Splicing

Post-transcriptional joining of exons in different combinations to make multiple proteins from one gene.

RNA Export

Transport of processed mRNA from nucleus to cytoplasm through nuclear pores.

microRNA (miRNA)

Small non-coding RNA that binds complementary mRNA and blocks translation or triggers degradation.

Protein Folding

Process by which a polypeptide acquires its functional three-dimensional shape, often aided by chaperones.

Post-translational Modification

Chemical alteration of a protein after translation affecting activity, stability, or location.

Mutation

Permanent change in DNA sequence.

Wild Type

Most common, standard form of a gene or trait in a population.

Mutant

Variant form of a gene that differs from the wild type.

Point Mutation

DNA alteration affecting a single nucleotide pair.

Substitution

Point mutation in which one base is replaced by another.

Insertion

Point mutation in which one or more bases are added to DNA.

Deletion

Point mutation in which one or more bases are removed from DNA.

Silent Mutation

DNA change that does not alter the amino acid sequence of the protein.

Missense Mutation

DNA change that substitutes one amino acid for another in a protein.

Nonsense Mutation

DNA change that converts an amino-acid codon into a stop codon, truncating the protein.

Frameshift Mutation

Insertion or deletion not in multiples of three that shifts the reading frame of a gene.

FOXP2 Gene Duplication

Evolutionary duplication linked to the development of human speech and language abilities.

5′→3′ Directionality

Orientation in which nucleic acid synthesis and decoding proceed.

Template DNA (tDNA)

DNA strand that serves as the pattern for RNA synthesis.

Non-template DNA (ntDNA)

DNA strand complementary to the template and identical to the RNA sequence (except T/U).

Amino Acid Sequence

Linear order of amino acids in a protein dictated by mRNA codons.