Molecular Genetics and DNA Technology Vocabulary

A complete set of vocabulary flashcards covering cell nucleus functions, DNA and RNA structure, protein synthesis, mutations, mitochondrial DNA, and modern DNA technology.

Nucleus

The cellular organelle that controls all activities of the cell, stores hereditary information, and contains the chromatin network that condenses into chromosomes.

Chromosomes

Long strands made up of DNA and histones (proteins) in the nucleus of the cell, which contain genetic information.

Histones

Proteins that provide structural support for DNA and help to condense and package DNA into chromosomes.

Gene

A segment of DNA that codes for proteins and acts as the basic unit of heredity.

Nucleotide

The monomer unit of DNA and RNA, consisting of a sugar, a phosphate group, and a nitrogenous base.

Genome

The complete set of genes or genetic material present in a cell or organism.

Purines

A group of nitrogenous bases that includes Adenine (A) and Guanine (G).

Pyrimidines

A group of nitrogenous bases that includes Cytosine (C) and Thymine (T) in DNA, and Uracil (U) in RNA.

Complementary Base Pairing

The pairing rule in nucleic acids where a purine always pairs with a pyrimidine base; Adenine pairs with Thymine (or Uracil in RNA) via 2 hydrogen bonds, and Guanine pairs with Cytosine via 3 hydrogen bonds.

Mitochondrial DNA (mtDNA)

Small amounts of nonrecombinant DNA present in the mitochondria of cells, inherited exclusively through the direct maternal line and coding for enzymes needed for cellular respiration.

Triplet Code

A sequence of 3 bases on a DNA strand that codes for 1 amino acid.

DNA Replication

The process of making new DNA from existing DNA, taking place during interphase before mitosis and meiosis.

Central Dogma

Francis Crick's theory stating that DNA makes RNA, and RNA makes protein.

Messenger RNA (mRNA)

A single-stranded RNA molecule that carries the encoded genetic message from DNA in the nucleus to the ribosome for protein synthesis.

Transfer RNA (tRNA)

A type of RNA involved in translation that carries a specific amino acid on one end and an anticodon on the other end to pair with mRNA codons.

Transcription

The first step of protein synthesis occurring in the nucleus, in which helicase unwinds DNA and RNA polymerase forms mRNA along the exposed DNA coding strand.

Translation

The second step of protein synthesis taking place in the cytoplasm, where ribosomes read mRNA codons and tRNA molecules deliver corresponding amino acids to form a polypeptide chain.

Codon

A group of 3 nucleotide bases on an mRNA strand that codes for 1 amino acid.

Anticodon

A group of 3 nitrogenous bases on a tRNA molecule that complementary base pairs with a specific codon on mRNA.

Start Codon

The mRNA codon AUG (methionine) which is always the first codon translated into a protein.

Stop Codons

The mRNA codons UGA, UAA, and UAG, which do not code for any amino acids and signal the termination of protein synthesis.

Substitution Mutation

A point mutation where one base pair in DNA is exchanged for another, which can alter an amino acid, remain silent, or create a premature stop codon.

Frameshift Mutation

A mutation caused by insertion or deletion of nucleotides in numbers not divisible by three, disrupting every downstream codon and altering the reading frame of DNA.

Mutagens

Physical agents (UV rays, X-rays, extreme heat) or chemical agents (cigarette smoke chemicals) that increase the rate of DNA mutation and can cause cancer.

Non-coding DNA

DNA regions that do not code for proteins but contain short tandem repeats (STRs) used in DNA profiling and regulate gene expression.

Restriction Enzymes

Enzymes used in DNA profiling to cut repeated DNA sequences (STRs) at the beginning and end, creating fragments of varying lengths.

Electrophoresis

A laboratory procedure used to separate cut DNA fragments according to size and length to produce a unique banding pattern.

Polymerase Chain Reaction (PCR)

A technique using DNA polymerase, primers, and free nucleotides to rapidly produce millions of copies of a specific DNA sequence within approximately two hours.

Codon Wheel

A visual reference wheel used to translate mRNA triplet codons into their corresponding amino acids.