DNA Biology and Biotechnology Vocabulary

Vocabulary practice flashcards covering DNA structure, replication, transcription, translation, and mutations from Chapter 21 lecture notes.

DNA (Deoxyribonucleic Acid)

A double-stranded nucleic acid located in the nucleus and mitochondria that contains adenine, thymine, guanine, and cytosine, and carries genetic information used to build proteins and regulate physiological processes.

RNA (Ribonucleic Acid)

A single-stranded nucleic acid found in the nucleus and cytoplasm that contains adenine, uracil, guanine, and cytosine, and functions in protein production, gene regulation, and protein regulation.

Nucleotide

The monomer building block of nucleic acids, consisting of a five-carbon sugar, a negatively charged phosphate group, and a nitrogenous base.

Ribose

The five-carbon pentose sugar present in RNA nucleotides.

Deoxyribose

The five-carbon sugar present in DNA nucleotides, which lacks an oxygen atom on the $2'$ carbon compared to ribose.

Purines

A class of double-ring nitrogenous bases consisting of Guanine (G) and Adenine (A).

Pyrimidines

A class of single-ring nitrogenous bases consisting of Cytosine (C), Thymine (T), and Uracil (U).

Photo 51

The famous X-ray diffraction image of DNA taken by Rosalind Franklin in 1953 that demonstrated its double helix structure, providing critical data for Watson, Crick, and Wilkins.

Antiparallel

The structural arrangement of DNA where one strand runs in the $5' \rightarrow 3'$ direction while the opposite strand runs in the $3' \rightarrow 5'$ direction.

Gene

A short segment of DNA that functions as a unit of heredity and codes for a specific protein or functional RNA molecule.

Genome

The complete set of genetic information for a species or organism.

Chromatin

The loose and relaxed structure composed of DNA and associated proteins found in eukaryotic cells when they are not dividing.

Chromosome

A highly condensed structure of chromatin formed when cells prepare to divide; human cells contain 23 pairs (46 total).

Semiconservative Replication

The mechanism of DNA replication occurring during S phase in which each newly formed DNA molecule consists of one original parent strand and one newly built daughter strand.

Helicase

An enzyme that unwinds and separates the two strands of the parental DNA double helix during replication.

DNA Polymerase

An enzyme that creates new DNA strands by adding complementary nucleotides to an RNA primer in the $5' \rightarrow 3'$ direction and proofreads for incorrect bases.

Primase

An enzyme that synthesizes a short RNA primer on the DNA template strand to initiate nucleotide addition by DNA polymerase.

Ligase

An enzyme that joins Okazaki fragments and seals nicks in the sugar-phosphate backbone during DNA replication.

Okazaki Fragments

Short, discontinuously synthesized DNA fragments produced on the lagging template strand during replication.

Promoter

A noncoding regulatory sequence at the start of a gene where transcription factors and RNA polymerase bind to begin transcription.

Terminator

A DNA sequence that signals RNA polymerase to halt transcription and release the RNA transcript.

Pre-mRNA

The initial, newly transcribed single-stranded RNA molecule containing both introns and exons that must undergo processing in the nucleus.

Introns

Non-coding sequence segments within pre-mRNA that are excised during RNA splicing and recycled.

Exons

Coding sequence segments within pre-mRNA that remain in mature mRNA to code for proteins.

Spliceosome

A nuclear complex assembled from snRNPs that removes introns from pre-mRNA and splices exons together to produce mature mRNA.

Messenger RNA (mRNA)

A type of RNA that carries genetic code decoded from DNA in three-base units called codons to direct protein synthesis at the ribosome.

Transfer RNA (tRNA)

An adapter RNA molecule with an anticodon loop that delivers specific amino acids corresponding to mRNA codons to the ribosome.

Ribosomal RNA (rRNA)

The RNA component of small and large ribosomal subunits that assembles with proteins in the nucleolus to catalyze protein synthesis.

Codon

A set of three consecutive mRNA nucleotide bases that specifies a particular amino acid or stop signal.

Start Codon

The mRNA triplet codon $AUG$ that sets the translation reading frame and codes for Methionine (Met).

Stop Codon

One of three mRNA triplet codons ($UAA$, $UAG$, $UGA$) that signals the termination of translation.

Anticodon

A three-nucleotide sequence on a tRNA molecule that base pairs complementarily with a codon on an mRNA strand.

Amino Acid

The monomer building block of proteins, composed of an $\text{-NH}_2$ amino group, a $\text{-COOH}$ carboxyl group, a central \text{C}_\text{\alpha} carbon, a hydrogen atom, and a variable R-group side chain.

Polypeptide Chain

A polymer made of amino acids linked together by peptide bonds formed between carboxyl and amino groups.

Chaperone Proteins

Proteins that assist newly translated polypeptide chains in folding properly into their functional configurations.

Mutation

A permanent change in the nucleotide sequence of a gene.

Frameshift Mutation

A mutation caused by the insertion or deletion of one or two nucleotides that completely shifts the downstream sequence out of its reading frame.

Thymine Dimers

A form of DNA damage induced by UV light radiation where adjacent thymine bases on a strand covalently bond to each other.