DNA

• DNA is found in the nucleus of eukaryote cells
• There are four bases of nitrogen in DNA: thymine, adenine, guanine, cytosine
• A purine always pairs with a pyrimidine, and a pyrimidine always pairs with a purine
• The purines are adenine and guanine
• The pyrimidines are thymine and cytosine
• AT 2, CG 3
• DNA has a double helix structure
• DNA is made up of many tiny monomers called nucleotides
• DNA is a polymer
• Nucleotides are made of phosphate, deoxyribose (sugar), and a nitrogeneous base
• Adenine only binds with thymine, cytose only binds with guanine
• Chromosomes are long strands of DNA wrapped around proteins called histones
• Genes are segments of DNA which code for a specific protein
• Alleles are different versions of the same gene
• Each cell has 46 chromosomes
• Watson, Crick, Wilkins, and Franklin were the four scientists credited for the discovery of DNA
• DNA contains hereditary information that is passed onto you from your parents
• A nucleotide's phosphate is attached to sugar which then attaches to another nucleotide's phosphate

  
• Hydrogen bonds join complementary nitrogenic bases together
• Covalent bonds join a nucleotide's sugar with another nucleotide's phosphate
• Female chromosomes are XX and male chromosomes are XY
• Autosomes are chromosomes which are responsible for all traits consistent across both genders
• A karyogram is an image showing the chromosomes that a cell has
• Humans have 46 chromosomes, forming 23 pairs
• Different alleles result in different traits for the same gene across different people
• Genotype


  The pair of alleles that an individual has
• Phenotype


  The physical characteristics of an individual, determined by the alleles in a genotype
• A homozygous genotype has two copies of the same allele (both dominant or both recessive)
• A heterozygous genotype has one dominant allele and one recessive allele
• A dominant allele will always be expressed over a recessive allele
• We have two alleles of each gene, one from each parent
• A homozygous recessive genotype is when both alleles are recessive, so the recessive gene gets expressed
• Some traits can be influenced by the environment that the individual lives in
• Dark and light conditions affect identical seeds differently
• A genotype is a complete genetic combination made from alleles
• Three nucleotides make an amino acid, 20 amino acids then join together to form protein
• The order of nucleotides in a gene determines the order of amino acids in a protein
• The order of nucleotides in a gene determines the order of amino acids in a protein which determines the shape of the protein which determines the function of the organism
• A genetic mutation is a change to the normal base sequence of a gene
• If the base sequence of a gene changes, the protein that it codes for might include different amino acids