DNA

• The genetic material in the nucleus of a cell is composed of a chemical called DNA. DNA is a polymer, a large and complex molecule. It is made up of two strands forming a twisted ladder structure called a double helix. It carries the genetic code, which determines the characteristics of a living organism.
• Except for identical twins, each person's DNA is unique. This is why people can be identified using DNA fingerprinting. DNA can be cut up and separated, which can form a 'bar code' that is different from one person to the next.
• Chromosomes - The cell's nucleus contains chromosomes. These are long threads of DNA, which are made up of many genes.
• A gene is a small section of DNA in a chromosome. Each gene codes for a particular sequence of amino acids in order to make a specific protein. It is the unit of heredity, and may be copied and passed on to the next generation.
• The genotype of an organism is its complete set of genetic material
• DNA

  Genetic material that determines inherited features
• DNA structure

  • Two strands
  • Strands are polymers
  • Strands wrap around each other to form a double helix
• Chromosome

  Contains DNA
• Gene

  Small section of DNA on a chromosome that encodes a specific sequence of amino acids to make a specific protein
• Humans have thousands of genes
• Chromosome 9 has over 700 different genes
• Both copies of chromosome 9 have the gene for blood type
• Genome

  The entire genetic material of an organism