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• DNA


  Deoxyribonucleic Acid
• Nucleotides


  • Phosphate group
  • Deoxyribose sugar
  • Nitrogenous base
• Complementary base pair


  • Adenine (A) and Thymine (T)
  • Cytosine (C) and Guanine (G)
• DNA replication


  The process by which DNA makes a copy of itself before cell division
• DNA replication


  1. DNA untwists and separates to expose nitrogenous bases

  2. Free nucleotides bond with the exposed nitrogenous bases following complementary base pairing rules

  3. Two identical strands of DNA are formed

  4. The two DNA strands are "proofread" and corrected by an enzyme if necessary
• DNA becomes visible in the cell when a cell prepares to reproduce
• Chromatin


  The form of DNA that is loosely packaged within the nucleus of a cell for most of the cell's lifecycle
• Chromosome


  The form of DNA that is condensed into a tight package when a cell prepares to reproduce
• Single stranded chromosome


  One copy of the genetic material
• Double stranded chromosome


  Two copies of the genetic material
• Chromatid


  Each individual copy of the genetic material within a chromosome
• Centromere


  The point where the two chromatids join in a double stranded chromosome
• Gene


  Small sections of DNA that determine the characteristics of an organism
• Genes

  The different order in which the nitrogenous bases are arranged within a gene are what gives an individual their unique characteristics
• Homologous pairs


  The 46 chromosomes in a human cell are organised into 23 pairs
• Karyotype


  A pictorial representation of all of the chromosomes in a cell
• Autosomes


  The first 22 pairs of chromosomes that determine the general characteristics and function of an organism
• Sex chromosomes


  The last two chromosomes that determine the gender of the individual