chapter 17 (corrected)

Gene expression

The process by which information from a gene is used to direct the synthesis of proteins and RNA.

Transcription

The process of copying the DNA sequence of a gene into messenger RNA (mRNA).

Translation

The process of using the sequence of codons in mRNA to assemble amino acids into a polypeptide chain.

Albinism

A genetic condition characterized by a lack of pigment resulting from a faulty gene responsible for synthesizing the pigment enzyme.

RNA polymerase

The enzyme responsible for synthesizing RNA from a DNA template during transcription.

Codons

Sequences of three nucleotide bases in mRNA that specify a particular amino acid.

One gene–one enzyme hypothesis

The theory that each gene corresponds to the production of a specific enzyme.

Haploid organism

An organism with only one copy of each gene, making it easier to study the effects of mutations.

Inborn errors of metabolism

Inherited metabolic disorders caused by defects in enzymes.

Spliceosome

A complex of proteins and RNAs that facilitates the removal of introns and joining of exons in the RNA splicing process.

Alternative splicing

A process allowing a single gene to produce multiple mRNA variants by including or excluding certain exons.

Ribozymes

RNA molecules that can catalyze biochemical reactions, typically involved in processes like RNA splicing.

5' cap

A modified guanine nucleotide added to the 5' end of mRNA that protects it from degradation and assists in ribosome binding.

Poly-A tail

A string of adenine nucleotides added to the 3' end of mRNA, aiding in stability and export from the nucleus.

Stop codons

Nucleotide sequences that signal the end of protein synthesis during translation.

Wobble hypothesis

The concept that the third base of a codon can undergo flexible base pairing, allowing a single tRNA to recognize multiple codons.

Point mutation

A mutation that involves a change in a single nucleotide pair in a gene, which can have various effects on protein function.

Frameshift mutation

A mutation caused by insertions or deletions that change the reading frame of the gene, often resulting in nonfunctional proteins.

CRISPR-Cas9

A technology that allows for precise gene editing, using a guide RNA to direct the Cas9 protein to a specific DNA sequence.

Transcription factors

Proteins that assist RNA polymerase in binding to the promoter to initiate transcription.

Mature mRNA

The final processed RNA transcript that is ready for translation, having undergone capping, polyadenylation, and splicing.