Genetics, Biodiversity and Classification

• Describe how a phosphodiester bond is formed between two nucleotides within a DNA molecule.

  Condensation reaction therefore loss of water;

  between phosphate and deoxyribose;

  catalysed by DNA polymerase.
• Name the protein associated with DNA in a chromosome.

  Histones.
• Give three ways in which the DNA in a chloroplast is different from DNA in the nucleus.

  In chloroplasts DNA is shorter, fewer genes and the DNA is circular not linear.
• Compare and contrast the DNA in eukaryotic cells with the DNA in prokaryotic cells.

  Eukaryotic DNA is linear, prokaryotic DNA is circular;

  Eukaryotic DNA contain introns, prokaryotic DNA does not;

  Eukaryotic DNA is longer;

  Eukaryotic DNA is associated with histones, prokaryotic DNA is not;

  Nucleotides joined by phosphodiester bond.
• In taxonomy, an organism is identified by referring to the species name and the genus name.

  What term is used to describe this method of naming organisms?

  Binomial.
• Explain the process of transcription.


  DNA helix unwinds;

  One chain of the DNA acts as a template;

  catalysed by DNA replication;

  Hydrogen bonds broken;

  Free mRNA nucleotides in nucleus aligns opposite exposed complementary DNA bases;

  RNA polymerase joins together the RNA nucleotides to create a new RNA polymer chain. One entire gene is copied.