Study Notes on Biotechnology and Stem Cells

Stem Cells: Unspecialized cells capable of differentiating into specialized cells.
- Types include:
- Pluripotent Stem Cells (HESC): Human Embryonic Stem Cells that can become every type of cell within the organism (Mpls).
  - Origin: Derived from the mass of cells in an embryo, specifically from frozen embryos or cloned embryos.
  - Characteristics:
  - More versatile compared to adult stem cells.
  - Less prone to mutations.
  - Epigenetic changes may occur but can trigger immune responses, resulting in unpredictability.
- Adult Stem Cells (Somatic Cells): Found in adult tissues, e.g., bone marrow.
  - Limited to turning into certain types of cells, e.g., blood cells.
  - Challenges:
  - Difficult to harvest.
  - Prone to mutations.
- Perinatal Stem Cells: Cells from the umbilical cord and placenta, available after birth.
  - Characteristics:
  - Potential for certain types of therapies.
  - Expensive storage and limited use.
- Induced Pluripotent Stem Cells (iPSCs): Adult somatic cells reprogrammed to revert to an embryonic state using specific chemicals.
  - Origin: Comes from the patient’s own cells.
  - Characteristics:
  - Carry risks of mutations.

Lab-Grown Cells/Cultures: Stem cells can create cell lines for research that descend from one original line.
- Historical Example: Henrietta Lacks’ cervical cancer cells, which are used extensively in research.
Repairing Damaged Tissues: Instead of relying on donor organs, lab-grown cells can repair damaged tissues such as bones, nerves, and skin.
Types of Stem Cells:
- Pluripotent Stem Cells: Found in embryos, with unlimited potential to become any cell type.
- Adult Stem Cells: Limited to certain cell types, recovered from bone marrow, blood cells, etc.
- Induced Pluripotent Stem Cells: Regressed somatic cells that revert to pluripotency through chemical means.
- Perinatal Stem Cells: Available post-birth, limited uses, and high cost.

Cloning: The making of identical copies of genes, cells, or whole organisms.

Therapeutic Cloning:
- Involves cloning an embryo to extract embryonic stem cells to grow specific tissues.
- Process involves:
- Isolating patient’s cells and removing the nucleus from an egg cell.
- Inserting the patient’s nucleus into the egg cell.
- The egg cell reprograms the DNA and begins dividing into a blastocyst, and the inner cell mass can be harvested for stem cells.
Reproductive Cloning: Making an identical organism.
- Example: Twinning from embryos, fertilizing eggs to create a blastocyst, and separating it into smaller groups for implantation into surrogates.
- Adult cell cloning uses Somatic Cell Nuclear Transfer (SCNT) to create clones.
- The nucleus of a body cell is inserted into an enucleated egg, growing it into an embryo which is then implanted into a surrogate.
- Applications: Cloning of animals, plants, and traits preservation.

Creation of Recombinant DNA: Combining DNA from two organisms (e.g., insulin gene inserted into bacterial plasmids).
- Plasmid: Circular unit of bacterial DNA that carries genes for antibiotic resistance.
- Restriction Enzymes: Used to cleave DNA for the insertion of new genes.
Transformation Procedure:
- Insert the plasmid back into bacteria using heat shock techniques, ensuring some bacteria uptake the plasmid.
- Only transformed bacteria survive and grow, producing a transgenic organism.
Culturing Transformed Bacteria:
- Grow bacteria on agarose gel plates with nutrients.
Gene Expression:
- The desired protein is expressed and harvested for pharmaceutical purposes (e.g., insulin).

Use in production of insulin, human growth hormones, and proteins for healing.
Risks associated with manipulation include creation of superbugs and the ethical use of technology in genetic modifications.