Genetics

• Genome - Entire genetic material of an organism.
• Chromosomes - Genetic structures found in nucleus made of DNA and proteins. Normally occur in functional pairs except in gametes and bacteria.
• Humans have 46 chromosomes (23 pairs) in every cell, except gametes which only have 23 chromosomes.
• Bacterial cells contain DNA in a circular chromosome in the cytoplasm (no nucleus) and as small rings of DNA called plasmids.
• Genes - Sections of chromosomes made up of short lengths of DNA that operate as functional units to control characteristics.
• Alleles - Different forms of the same gene.
• Double stranded DNA molecule = double helix

  DNA is made of repeating units called nucleotides.

  Each nucleotide is made of sugar called deoxyribose, a phosphate and a base.
• DNA has a sugar phosphate backbone with interlinking bases to form a double helix.

  C always pairs with G

  A always pairs with T
• Coding Strand - one strand of DNA molecules carries genetic code.
• Base triplet - Every 3 bases forms code for one amino acid.
• Mitosis - Duplication of chromosomes producing daughter cells, clones, genetically identical.
• Haploid - Cell/nucleus with half the normal number of chromosomes (23).
• Diploid - Cell/nucleus with the normal number of chromosomes (46).
• Meiosis - Reduction division, production of cells with half the normal number of chromosomes.

  Only occurs in sex organs to produce gametes.
• Gametes - contain one allele for each characteristic.
• Dominant Allele - when present, characteristic shows.
• Recessive Allele - requires both alleles to be recessive for characteristic to show.
• Genotype - 2 letters which represent alleles.
• Phenotype - Actual characteristic / appearance.
• Homozygous Genotype - two alleles are the same e.g., BB
• Heterozygous Genotype - two alleles are different e.g., Bb
• Producing Insulin by Genetic Engineering

  1. Gene that codes for insulin cut from DNA using a restriction enzyme.
  2. Same enzyme used to cut ring of DNA, plasmid, from bacterium.
  3. Join human insulin gene to open plasmid.
  4. Plasmid taken up by bacterial cell again.
  5. Bacterium is allowed to reproduce.
  6. Given best conditions in fermenter / bioreactor to produce millions of cells, all of which will produce insulin.
  7. Downstreaming to produce pure form of insulin.
• Downstreaming - Insulin extracted from bacteria, purified and packaged.
• Advantages of Insulin Production through Genetic Engineering

  • Faster extraction process.
  • Human insulin is most effective.
  • Animal insulin = ethical issues.
  • Larger quantities produced.
  • Pure form.
  • Cheaper.