Chapter 4, Lesson 2: Genes and Their Action

Flashcards from Chapter 4, Lesson 2 of McGraw Hill Anatomy and Physiology, Ninth Edition, by Kenneth S. Saladin.

Gene

An information-containing segment of DNA that codes for the production of RNA which in turn helps synthesize proteins

Genome

All the DNA in one 23 chromosome set

Genomics

The study of the whole genome

Genomic medicine

The application of knowledge of the genome to the prediction, diagnosis, and treatment of disease

Base triplet

Sequence of three DNA nucleotides that stand for one amino acid

Codon

A three base sequence in RNA

Start codon

Begins the amino acid sequence of the protein (AUG for methionine)

Stop codon

Ends the amino acid sequence like a period (UAG, UGA, and UAA)

Transcription

Copying the genetic instructions from DNA to mRNA

RNA polymerase

Binds to DNA and opens up the helix; reads bases from one strand of DNA to build a complementary strand of mRNA; then rebinds it

Pre-mRNA

Immature RNA produced by transcription

Exons

Segments of pre-mRNA exported from the nucleus and translated into protein which are spliced by enzymes

Introns

Segments of pre-mRNA that will be removed before translation

Messenger RNA (mRNA)

Carries code from the nucleus to cytoplasm and ribosome

Transfer RNA (tRNA)

Delivers a single amino acid to the ribosome; includes three nucleotides called an anti-codon to bind to mRNA and bring free amino acid using one ATP

Ribosome

Organelles that read mRNA and build peptide chains from amino acids; pulls mRNA through like a ribbon

Initation

Leader sequence in mRNA binds to a ribosomal subunit, joining the complex ribosome and allows for reading

Elongation

tRNA binds to the ribosome to pair with mRNA, brings amino acids to form a peptide bond

Termination

Releasing a protein and mRNA after reaching a stop codon; proteins may need to be packaged or exported

Chaperone proteins

Guides the folding of new proteins into secondary and tertiary structures; defends against heat or stress into correct shapes

Posttranslational modification

Proteins made on the ER are threaded into pores and enzymes to modify the protein through amino acid trimming, folding, and stabilization