Biotechnology Fundamentals

Study Notes

Biotechnology includes introduction to biotechnology, fundamental principles, genetic engineering techniques, omics sciences, and biotechnology applications.

Rosalind Franklin obtained images of DNA using X-ray crystallography in 1953, which led to James Watson and Francis Crick's double-helix model.
DNA is composed of two chains that coil around each other to form a double helix.
The DNA structure consists of a right-handed double helix, with a hydrophilic backbone of alternating deoxyribose and phosphate groups facing outwards.
Purine and pyrimidine bases are hydrophobic and stacked inside the double helix, stabilized by hydrophobic interactions and perpendicular to the long axis.
Base pairing occurs due to hydrogen bond interactions, with purine pairing with pyrimidine (A-T and C-G).

A and G are long (double-ring purines), while C and T are short (single-ring pyrimidines).
One long and one short nucleotide are needed per pair.
C-G has three hydrogen bonds, while A-T has two hydrogen bonds.

DNA strands interact in an antiparallel orientation, with sequences being complementary to one another.
The stacked bases are 3.4 Å apart.
The base pairing of the two strands creates a major groove and a minor groove on the surface of the duplex.

Genes are stretches of information in the sequence that encode for a particular function, usually a protein or RNA sequence.
There are approximately 20,000 genes in humans, typically 1000s of nucleotides long.
Genes can be expressed or repressed, and regions of DNA are divided into coding and non-coding segments.
Over 50% of human DNA is non-coding.

The complete set of genes or genetic material present in a cell or organism is known as the genome.
In bacteria, the genome is usually circular, while in eukaryotes, it is organized into chromosomes.
Each chromosome is a separate DNA molecule, with human cells containing 46 chromosomes.
Chromosomes are extended and replicated during interphase, and condensed during cell division.
DNA wraps around protein "spools" to form nucleosomes, made of histone proteins.