Teacher note

Nucleic Acids

Large polymers composed of nucleotide monomers that store genetic information and help produce proteins.

DNA

Deoxyribonucleic Acid, the blueprint of life consisting of two antiparallel strands.

RNA

Ribonucleic Acid, a single strand of nucleotides involved in protein synthesis.

Nucleotides

Building blocks of nucleic acids, consisting of a phosphate group, sugar, and nitrogenous base.

Deoxyribose

The 5-carbon sugar molecule present in DNA.

Nitrogenous Bases in DNA

Adenine (A), Thymine (T), Cytosine (C), Guanine (G).

Phosphate group

Negatively charged group (PO4) that links nucleotides together.

Adenine

A nitrogenous base that pairs with Thymine in DNA.

Thymine

A nitrogenous base that pairs with Adenine in DNA.

Cytosine

A nitrogenous base that pairs with Guanine in DNA.

Guanine

A nitrogenous base that pairs with Cytosine in DNA.

Antiparallel

The orientation of the two polynucleotide strands of DNA running in opposite directions.

DNA Polymerase

An enzyme that adds nucleotides to the growing DNA chain during replication.

Double Helix

The twisted ladder shape of the DNA molecule formed by two strands.

Histones

Proteins that package DNA into structures called nucleosomes in eukaryotic cells.

Nucleosome

A structural unit of DNA wrapped around a core of histone proteins.

Chromatin

A complex of DNA and proteins that forms chromosomes within the nucleus.

Introns

Non-coding regions of DNA that are eliminated during RNA processing.

Exons

Coding segments of DNA that are spliced together to form mature mRNA.

Promoter Region

Sequence where RNA polymerase binds to initiate transcription.

Operator

Binding site for repressor proteins that inhibit transcription.

Transcription

The process of copying DNA into pre-mRNA.

Translation

The process of decoding mRNA into a polypeptide chain (protein) at the ribosome.

Codon

A group of three nucleotides in mRNA that codes for a specific amino acid.

Triplet

A group of three adjacent nucleotides in DNA that codes for an amino acid.

RNA processing

Modifications made to pre-mRNA to convert it to mature mRNA.

Splicing

The removal of introns and joining of exons to form mature mRNA.

Capping

Addition of a methyl cap at the 5’ end of mRNA for protection.

Poly-A tail

Addition of a chain of adenine nucleotides at the 3’ end of mRNA for stability.

tRNA

Transfer RNA that brings amino acids to the ribosome during protein synthesis.

Anti-Codon

Triplet unit located on tRNA that is complementary to the mRNA codon.

Trp Operon

A regulatory system in E. coli that controls the production of tryptophan.

Operator (trp operon)

The site where the repressor protein binds to inhibit transcription of the trp genes.

Attenuation

A regulatory mechanism in the trp operon that affects transcription termination.

Leader Sequence

A stretch of mRNA that contains regions that can form base-paired structures to regulate transcription.

Inducible Operon

An operon that can be turned on or off based on substrate levels, like tryptophan.

Termination Sequence

Sequence that signals the end of transcription in gene expression.

RNA polymerase

Enzyme responsible for synthesizing RNA from a DNA template during transcription.

Amino Acid

Building blocks of proteins coded for by codons in mRNA.

Proteins

Molecules made up of amino acids that perform various functions in organisms.

Gene Structure

The arrangement of coding and non-coding sequences in a gene, including promoter, exons, and introns.

Mature mRNA

The final product after RNA processing, ready for translation.

Ribosome

The cellular structure where translation occurs and proteins are synthesized.