Products of Biotechnology

Why can't biotech drugs be made through chemical synthesis like small molecules?

Proteins are too large and structurally complex to build atom-by-atom; living cells' protein-making machinery must be used instead

What two enzymes are essential to recombinant DNA technology, and what does each do?

Restriction endonucleases cut DNA at specific sites (molecular scissors); DNA ligase joins DNA pieces together (molecular glue)

Why can a bacterium produce a human protein from a human gene?

The genetic code is universal, so bacteria read and translate the human gene using the same DNA-to-protein machinery as human cells

What gene encodes human insulin and where is it located?

The INS gene, 1,425 base pairs, located on chromosome 11

List the steps of basic recombinant insulin production

Insert insulin gene into plasmid, introduce plasmid into bacterium, grow in fermentation tank, bacteria produce insulin, harvest and purify

In the two-chain insulin production method, why are chains A and B fused to β-galactosidase first?

Small peptides like insulin subunits are unstable/degraded alone in bacteria; fusing them to a stable bacterial protein protects them until purification and cleavage

How are functional insulin A and B chains ultimately joined?

Chemically cleaved from their fusion proteins, then combined to form a disulfide bridge, producing active insulin

What is the purpose of antibiotic resistance genes in plasmid vectors?

They allow selection of bacteria that successfully took up the recombinant plasmid (transgenic cells)

What is a DNA probe and how does it work?

A synthetic DNA fragment tagged with dye/radioactive isotope that binds only to a complementary matching sequence, revealing viral genes or genetic defects

What is the difference between a sense and antisense sequence?

Sense sequence carries protein-building information; antisense sequence is complementary to it

How do antisense drugs work?

They bind to target mRNA, blocking translation and often destroying the mRNA, preventing unwanted protein synthesis

Why is antisense technology called "reverse genetics"?

Because it works backward from a known disease mechanism to design a molecule that interferes with it, rather than discovering a drug empirically first

What is Fomivirsen used for?

Local treatment of CMV retinitis in AIDS patients intolerant of other CMV treatments

What deficiency causes hemophilia A?

Deficiency of clotting Factor VIII

What do colony-stimulating factors (CSFs) do?

Bind marrow cell receptors to control proliferation/differentiation into specific blood cell types (neutrophils, monocytes, etc.)

What is Filgrastim used for and what does it stimulate?

G-CSF; stimulates neutrophil production; used for chemotherapy-related neutropenia

What is unique about how Sargramostim (GM-CSF) is produced?

Produced in yeast (Saccharomyces cerevisiae) via rDNA, rather than bacteria

Why might yeast be chosen over bacteria as a host organism for some biotech drugs?

Yeast can perform more complex post-translational modifications (e.g., glycosylation) than bacteria

What does erythropoietin do naturally?

A kidney-produced glycoprotein stimulating proerythroblast formation and reticulocyte release from bone marrow

What is the first lab sign that Epoetin alfa is working?

A rise in reticulocyte count, before hemoglobin itself increases

Why is Darbepoetin alfa produced in Chinese hamster ovary (CHO) cells?

Glycoprotein hormones require mammalian-style sugar attachments that bacteria cannot correctly produce

What does human growth hormone (hGH) stimulate besides bone growth?

Skeletal muscle cell size/number, organ size, and red cell mass via EPO stimulation

What do tissue plasminogen activators (tPA) do, mechanistically?

Convert plasminogen to plasmin, which breaks down fibrin, the main clot protein

Conceptually, how do clotting factors and tPA agents have opposite roles?

Clotting factors promote clotting (replace missing factor); tPA agents dissolve existing clots

What is Alteplase used for?

Acute myocardial infarction, acute ischemic stroke, and pulmonary embolism

How do genetically engineered vaccines avoid using live virus?

They use a synthetic copy of the virus's protein coat to trigger immune recognition without risk of causing disease

What is the standard dosing schedule for recombinant Hepatitis B vaccine?

3 doses at 0, 1, and 6 months

Name four different SARS-CoV-2 vaccine platform types

mRNA, adenovirus-vectored, inactivated virus, protein subunit

How do Goserelin and Leuprolide work paradoxically?

Continuous administration of these GnRH/LHRH analogs suppresses the reproductive hormone axis, causing medical castration, used for prostate cancer

What does Rasburicase do?

Enzymatically converts uric acid into soluble allantoin, preventing tumor lysis syndrome during chemotherapy

List four major challenges facing protein-based biotech drugs

Intrinsic instability, poor GI absorption, limited tissue penetration, immunogenicity/allergic reaction risk

Why are almost all biotech drugs administered by injection rather than orally?

Proteins would be digested/broken down like food if taken orally due to poor GI absorption