chapter 17

Gene

A section of DNA that contains instructions for making a specific protein.

Amino Acid

The building blocks of proteins; they link together to form polypeptides.

Polypeptide

A chain of amino acids that can fold into a functional protein.

Protein

A molecule made up of one or more polypeptide chains that perform various functions in the body.

DNA Replication

The process of making an exact copy of DNA before a cell divides.

Transcription

The process of copying a gene's DNA sequence to make messenger RNA (mRNA).

Translation

The process where ribosomes read mRNA and assemble amino acids into a protein.

Eukaryote

A type of organism whose cells have a nucleus, such as animals and plants.

Messenger RNA (mRNA)

A type of RNA that carries genetic information from DNA to the ribosome for protein synthesis.

Ribosomal RNA (rRNA)

A component of ribosomes that helps in the process of translation.

Transfer RNA (tRNA)

A type of RNA that brings amino acids to the ribosome during protein synthesis.

Codon

A sequence of three nucleotides in mRNA that corresponds to a specific amino acid or stop signal during translation.

Ribosome

A cellular structure where protein synthesis occurs, made up of rRNA and proteins.

A Site

The ribosomal site where the tRNA carrying the next amino acid enters.

P Site

The ribosomal site where the tRNA carrying the growing polypeptide chain is located.

E Site

The ribosomal site where empty tRNA exits after its amino acid has been added to the chain.

Anticodon

A sequence of three nucleotides on tRNA that pairs with a codon on mRNA.

Nucleotide

The basic building block of DNA and RNA; consists of a sugar, a phosphate group, and a nitrogenous base.

Base Pairing Rules

Rules that dictate how nucleotides pair in DNA (A with T, C with G) and in RNA (A with U, C with G).

Mutation

A change in the DNA sequence that can lead to changes in protein function.

Point Mutation

A mutation that affects a single nucleotide in the DNA sequence.

Nucleotide Insertion

A mutation where one or more nucleotides are added to the DNA sequence.

Nucleotide Deletion

A mutation where one or more nucleotides are removed from the DNA sequence.

Silent Mutation

A mutation that does not change the amino acid sequence of a protein.

Nonsense Mutation

A mutation that creates a stop codon, leading to premature termination of protein synthesis.

Missense Mutation

A mutation that changes one amino acid in the protein sequence.

Codon Chart

A table used to identify which amino acid corresponds to each codon in mRNA.

Central Dogma

The flow of genetic information from DNA to RNA to protein.