Review: Unit 4 Gene Expression

A codon is a sequence of three nucleotides in mRNA that specifies a particular amino acid.

AUG is known as the start codon.

A polypeptide is a chain of amino acids linked together by peptide bonds.

Peptide bonds hold amino acids together in a polypeptide.

The 3D shape of a protein is crucial for its function; it determines how the protein interacts with other molecules.

mRNA (messenger RNA) carries the genetic code from the DNA in the nucleus to the ribosomes in the cytoplasm for protein synthesis.

Transcription occurs in the nucleus where DNA is located.

DNA cannot leave the nucleus because it is too large and must remain protected.

tRNA (transfer RNA) brings amino acids to the ribosome during protein synthesis.

Ribosomes are the sites where mRNA is translated into a polypeptide chain.