Biotechnology Fundamentals

Biotechnology

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

DNA Structure

• 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).

Base Pairing

• 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

• 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.

Gene and Genome

• 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.

Genome Organization

• 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.