DNA

• DNA Stands for deoxyribonucleic acid. It is a special compound that exists in all of our cells.
• DNA determines many of the characteristics that we posses
• DNA is made up of three different parts

  1. Sugar
  2. Phosphate
  3. Nucleic bases
• The 4 types of nucleic bases are:

  1. Adenine
  2. Thymine
  3. Guanine
  4. Cytosine

  Base pairs only go together, they're AT and GC
• Characteristics can be categorised in two waysh

  1. Physical
  2. Physiological
• Physical characteristics refer to any characteristics regarding you body

  E.g. Eye colour, hair colour, height
• Physiological characteristics refer to any internal processes

  E.g. metabolism
• Genes are small segments of our DNA. While DNA is responsible for determining our characteristics, genes are the specific combination of nitrogenous base pairs the create certain characteristics.
• Phenotype = The appearance of the organism caused by its genes. E.g. Genotype “tt” results in phenotype “dwarf”. Phenotype “TALL” could have genes “TT” or “Tt”
• Genotype = The genes an individual has for a characteristic e.g. a dwarf has the genotype “tt”. Genotype “Tt” would grow tall.
• Homozygous = Have 2 genes the same. E.g. “TT” or “tt”
• Heterozygous = Having 2 different genes E.g. “Tt”
• Alleles = The alternative gene for a characteristic e.g. “T” and “t” are the alleles for stem height in Mendel’s peas. (Specifies the trait, allele specifies the form the gene takes)
• Gene = A unit with coded genetic information. Found on a chromosome
• A chromosome is a thread like string of genes
• Nucleus: the cell structure that contains the chromosomes
• DNA = chemical substance that makes up chromosomes
• Mutation = mistake in the genetic code
• What is DNA


  Chemical substance that makes up chromosomes
• Heritable characteristics are transmitted to successive generations, which involves the passing of genetic information from parents to offspring.
• Transmission occurs through:

  1. DNA replication
  2. Meiosis
  3. Sexual Reproduction
• • Why is it important for DNA to replicate exactly?

  Leads to mutations if DNA does not replicate correctly

  It is also beneficial, limiting or neutral
• Mitosis = A type of cell division in which one cell (the mother) divides to provide two new cells (the daughters) that are genetically identical to itself
• There are 3 types of mutations: beneficial, neutral, and harmful
• Where is DNA located?

  In the cell nucleus
• genes are passed down in the DNA of chromosomes
• heritable traits are passed down through generations via DNA and genes