Biotechnology Fundamentals and Applications
What this domain tests
Biotechnology Fundamentals and Applications tests the molecular and process science behind bioindustry. Expect questions on recombinant DNA, expression systems, fermentation, purification, analytics, and applications from diagnostics to biologics.
Core rules
- Central dogma: DNA → RNA → protein. Recombinant production requires a vector, a host, selection, and control of expression.
- Host choice matters: E. coli is fast and cheap but does not glycosylate proteins; yeast can secrete and glycosylate, though with different glycan patterns; CHO cells are common for complex therapeutic proteins; insect and plant systems have niche uses.
- Upstream: batch, fed-batch, and perfusion cultures are controlled by pH, dissolved oxygen, temperature, and nutrient feed. Plasmid instability and overflow metabolism can limit yield.
- Downstream: harvest, clarification, chromatography (affinity, ion exchange, size exclusion), viral inactivation, filtration, and formulation. Each step must preserve product quality.
- Analytics: PCR, qPCR, sequencing, ELISA, HPLC, mass spectrometry, and bioassays support identity, purity, potency, and safety.
- Applications: vaccines, monoclonal antibodies, gene therapy, synthetic biology, industrial enzymes, and diagnostics.
Worked example
A team expresses a human glycoprotein in E. coli and finds insoluble inclusion bodies. The host cannot add human glycans, and the protein may need refolding. For a glycosylated therapeutic, a better choice may be CHO or another mammalian system. If E. coli is retained, the process must include solubilization, refolding, and glycan-independent quality checks. The reasoning is that host biology and product critical quality attributes must match.
Traps that cost marks
- Assuming E. coli performs human glycosylation.
- Ignoring codon bias or rare tRNAs.
- Forgetting plasmid stability in long fermentations.
- Treating purification as a single chromatography step.
- Using PCR without contamination controls.