Life Science Uge 13: Chapter 18: Recombinant DNA and Biotechnology Vocabulary

A complete set of vocabulary flashcards covering recombinant DNA technology, cloning vectors, gene editing, and applications in biotechnology.

Expression Vector (ekspressionsvektor)

A specialized vector (vektor) containing regulatory sequences—such as a promoter (promotor), ribosome-binding site (ribosombindingssted), and transcription terminator (transkriptionsterminator)—required for a transgene (transgen) to be transcribed and translated in a host cell (værtscelle).

Bioreactor (bioreaktor)

An industrial vessel or system used to cultivate living cells or transgenic organisms (transgene organismer) under controlled physical and chemical conditions to maximize recombinant protein (rekombinant protein) production.

Transgenic Organism (transgen organisme)

A host cell or organism (værtsorganisme) that contains inserted, non-native recombinant DNA (rekombinant DNA) stably integrated into its genome.

Genetically Modified Organisms (GMO) (genmodificerede organismer (GMO))

Organisms whose genetic material (genetisk materiale) has been artificially altered using recombinant DNA technology (rekombinant DNA-teknologi) and genetic engineering.

Pharming (pharming)

The production of useful medical proteins or pharmaceuticals in transgenic farm animals (transgene landbrugsdyr) or plants, such as secreting human therapeutic proteins into livestock milk.

Synthetic Biology (syntetisk biologi)

An interdisciplinary field combining engineering and biology to design, construct, or rebuild artificial genomes (kunstige genomer), pathways, and living cells with novel functions.

RNA Interference (RNAi) (RNA-interferens (RNAi))

A biological mechanism where small single- or double-stranded RNA molecules (such as miRNAs or siRNAs) target specific complementary MRNA (mRNA) sequences to block translation or trigger degradation.

Gene Knockout (gen-knockout)

A genetic technique in which an organism's gene is permanently inactivated or deleted to investigate its normal biological function and phenotypic effects.

Stem Cells (stamceller)

Undifferentiated biological cells that can undergo self-renewal through cell division and differentiate into specialized functional cell types.

Totipotent Stem Cells (totipotente stamceller)

Cultured or zygotic cells that possess the developmental potential to differentiate into any cell type of an organism, including extraembryonic tissues like the placenta.

Pluripotent Stem Cells (pluripotente stamceller)

Stem cells capable of differentiating into all body cell types of the embryo proper, derived from all three germ layers, but unable to form extraembryonic tissues.

Multipotent Stem Cells (multipotente stamceller)

Stem cells with a restricted developmental potential, capable of differentiating into a limited subset of cell types within a specific lineage or tissue.

Induced Pluripotent Stem Cells (iPS cells) (inducerede pluripotente stamceller (iPS-celler))

Differentiated adult somatic cells (somatiske celler) that have been genetically reprogrammed back into an embryonic-like pluripotent stem cell state.

DNA Microarray (DNA-mikroarray)

A grid of microscopic spots containing attached oligonucleotide probes (oligonukleotidprober), used to analyze global gene expression patterns (genudtryksmønstre) across an entire genome simultaneously.

Recombinant DNA (rekombinant DNA)

A synthetic DNA molecule formed in the laboratory by combining genetic material from at least two different biological sources.

Restriction Enzymes (restriktionsenzymer)

Enzymes that cleave double-stranded DNA at specific palindromic recognition sequences known as restriction sites (restriktionsskæringssteder).

Sticky Ends (klæbrige ender)

Short complementary single-stranded DNA overhangs created when restriction enzymes make staggered cuts at restriction sites.

Selectable Marker (selektionsmarkør)

A gene (such as one conferring antibiotic resistance) included in a vector to identify, select, and isolate host cells that have successfully taken up recombinant DNA.

Reporter Gene (reportergen)

A gene whose phenotype is easily observed and measured (such as GFP or lacZ), used to select transformed host cells or monitor promoter regulation.

Reverse Transcriptase (omvendt transkriptase)

An enzyme that catalyzes the synthesis of complementary DNA (cDNA) from an RNA template via complementary base pairing.

How does an expression vector (ekspressionsvektor) differ functionally from a standard cloning vector (kloningsvektor) in host cells?

Expression vectors (ekspressionsvektor) contain host-recognized regulatory elements—such as a promoter (promotor), ribosome-binding site (ribosombindingssted), and transcription terminator (transkriptionsterminator)—allowing the transgene to be actively expressed into protein, whereas standard cloning vectors (kloningsvektor) only replicate foreign DNA.

What is the primary mechanism of action of tissue plasminogen activator (TPA) (vævsplasminogenaktivator (TPA)) in treating ischemic stroke (iskæmisk slagtilfælde)?

TPA (vævsplasminogenaktivator (TPA)) catalyzes the dissolution of blood clots (blodpropper) blocking oxygen supply in brain arteries, restoring tissue respiration before irreversible cell death occurs.

Why are complementary overhangs known as sticky ends (klæbrige ender) preferred over blunt ends (stump ender) when joining DNA fragments?

Sticky ends (klæbrige ender) form specific hydrogen bonds (hydrogenbindinger) between complementary base pairs on vector and insert, greatly facilitating stable joining by DNA ligase (DNA-ligase) compared to non-specific blunt ends.

How did Stanley Cohen and Herbert Boyer confirm that their artificial recombinant plasmid (rekombinant plasmid) was functional in E. coli (E. coli)?

They transformed E. coli (E. coli) with plasmids containing resistance genes for both kanamycin and tetracycline, showing transformed cells survived on growth media containing both antibiotics (antibiotika).

What three essential features must be present in a bacterial cloning plasmid vector (bakteriel plasmidvektor)?

1. An origin of replication (ori) (replikationsstart) for autonomous replication. 2. A selectable marker (selektionsmarkør) for identifying host cells. 3. Unique restriction sites (restriktionsskæringssteder) for inserting foreign DNA.

How does the Ti plasmid (Ti-plasmid) of Agrobacterium tumefaciens (Agrobacterium tumefaciens) transfer genes into plant cells?

The bacterium infects plant tissue and transfers a specific segment of the plasmid called T DNA (T-DNA), which stably incorporates directly into host plant chromosomes (plantekromosomer).

In blue-white screening with lacZ (lacZ-screening), why do white bacterial colonies indicate successful recombinant plasmid insertion?

Foreign DNA insertion inside the lacZ gene (lacZ-gen) inactivates beta-galactosidase (beta-galaktosidase) production, preventing the cleavage of X-Gal (X-Gal) into a blue product, leaving transformed colonies white.

How does green fluorescent protein (GFP) (grønt fluorescerende protein (GFP)) serve as a protein tag in eukaryotic cells?

The coding sequence of GFP (grønt fluorescerende protein (GFP)) is attached to a target gene; upon expression, the tagged protein emits green light under ultraviolet light (UV-lys) to reveal its location without killing the host cell.

How does the structural composition of a cDNA library (cDNA-bibliotek) differ from a genomic DNA library (genomisk DNA-bibliotek)?

A cDNA library (cDNA-bibliotek) is synthesized from mRNA (mRNA) using reverse transcriptase (omvendt transkriptase), containing only expressed exons (eksoner), whereas a genomic library contains all genomic DNA including non-coding introns (introner) and promoters.

Why are cDNA libraries (cDNA-biblioteker) constructed from brain and liver tissue of the same human different, while their genomic libraries (genomiske biblioteker) are identical?

Genomic DNA is identical across all somatic cells, but different tissues express distinct sets of genes into mRNA (mRNA), producing tissue-specific cDNA libraries (cDNA-biblioteker).

What function does reverse transcriptase (omvendt transkriptase) perform during RT-PCR (RT-PCR)?

Reverse transcriptase (omvendt transkriptase) converts isolated mRNA (mRNA) into single-stranded complementary DNA (cDNA) prior to standard PCR amplification.

How does a DNA microarray (DNA-mikroarray) quantify differential gene expression between normal tissue and tumor tissue?

Fluorescently labeled cDNAs from normal tissue (e.g., green) and tumor tissue (e.g., red) competitively hybridize to spot-attached oligonucleotide probes; relative fluorescence intensity indicates gene upregulation or downregulation.

By what mechanism does synthetic antisense RNA (antisense-RNA) prevent translation of target mRNA?

Antisense RNA (antisense-RNA) is complementary to target sense mRNA; upon hybridization, it forms a double-stranded RNA molecule that sterically blocks ribosome translation (translation).

How does the RNA-induced silencing complex (RISC) (RNA-induced silencing complex (RISC)) reduce target gene expression using siRNAs?

Single-stranded siRNA guides RISC (RISC-kompleks) to complementary target mRNA (mRNA), triggering catalytic cleavage and degradation of the mRNA transcript.

What dictates the sequence specificity of CRISPR-Cas9 (CRISPR-Cas9) target gene editing in host genomes?

A synthetic guide RNA (gRNA) (guide-RNA) designed with a sequence complementary to the target locus directs the CAS9 nuclease (CAS9-nuklease) to create a double-strand break (dobbeltslagsbrud) at that specific genomic site.

What structural modification occurs when double-strand breaks caused by Cas9 (Cas9) are repaired via non-homologous end joining (NHEJ) (ikke-homolog endesammenføjning)?

NHEJ (ikke-homolog endesammenføjning) is error-prone, introducing insertion or deletion mutations (indels) that cause frameshifts or premature stop codons, knocking out gene function.

How can CRISPR-Cas9 (CRISPR-Cas9) be adapted to create a specific point mutation rather than a gene knockout?

A custom repair DNA template containing the desired mutation is introduced alongside Cas9 and guide RNA; host homology-directed repair pathways incorporate the template sequence during DNA break repair.

How can a catalytically dead Cas9 (dCas9) (katalytisk inaktiv Cas9) be used to knock down gene expression without introducing double-strand breaks?

dCas9 (dCas9) retains guide RNA binding but lacks cleavage activity; when targeted to a promoter region, its presence physically blocks RNA polymerase (RNA-polymerase) transcription.

What is the primary technical advantage of pharming (pharming) therapeutic human proteins in transgenic mammals over bacterial expression systems?

Transgenic mammals perform complex eukaryotic post-translational modifications (posttranslationelle modifikationer) (such as glycosylation) and secrete large quantities of functional protein into milk.

How does transgenic Bt corn (Bt-majs) protect crops against herbivorous insect pest larvae?

Bt corn contains a transgene from Bacillus thuringiensis (Bacillus thuringiensis) encoding a protein toxin that binds insect midgut cell receptors, creating fatal membrane pores.

What mechanism enables glyphosate-resistant crops (glyphosat-resistente afgrøder) to survive broad-spectrum herbicide applications?

Transgenic plants express an insensitive bacterial form of the target chloroplast enzyme, allowing essential amino acid synthesis (aminosyresyntese) to continue in the presence of glyphosate.

How does Golden Rice 2 (Gylden Ris 2) combat nutritional vitamin A deficiency (vitamin A-mangel)?

Golden Rice 2 expresses engineered genes from corn and bacteria in its grain endosperm, producing high amounts of beta-carotene (beta-caroten), a precursor converted into vitamin A upon ingestion.

What developmental distinction separates totipotent stem cells (totipotente stamceller) from pluripotent stem cells (pluripotente stamceller)?

Totipotent stem cells (totipotente stamceller) can form all cell types of an organism including extraembryonic tissues (like placenta), whereas pluripotent cells can form all embryonic tissues but not extraembryonic tissues.

How are induced pluripotent stem cells (iPS cells) (inducerede pluripotente stamceller (iPS-celler)) engineered in the laboratory?

Differentiated somatic adult cells are transfected with specific pluripotency transcription factors, reprogramming their gene expression back to an embryonic pluripotent state.

How are transgenic multicellular animals generated using transformed totipotent stem cells (totipotente stamceller) in culture?

Transformed stem cells are injected into an early embryo blastocyst (blastocyst), producing a chimeric animal whose transgenic germ cells pass the transgene to offspring in subsequent generations.