B6

• DNA


  Deoxyribonucleic acid, the chemical that all of our genetic material is made of
• DNA


  • It's a polymer made up of lots of similar units stuck together
  • It has two strands which are stuck together to form a double helix
• Chromosome


  A really tight coil of DNA, each cell has 46 chromosomes
• There are 23 different types of chromosomes, with two of each type (one from each parent)
• Sex chromosomes


  The 23rd pair, consisting of an X chromosome and a Y chromosome
• Chromosomes only look like an X shape just before cell division
• Gene


  A small section of DNA that codes for a particular type of protein
• There are 20 different types of amino acids, which can be combined in many different sequences to form thousands of different proteins
• Genome


  The entire set of genetic material in an organism
• Genomes can be used to trace the migrations of human ancestors
• Allele


  Different versions of the same gene
• Homozygous


  Having two of the same alleles for a particular gene
• Heterozygous


  Having two different alleles for a particular gene
• Dominant allele


  The allele that gets expressed when present, regardless of whether the organism is homozygous or heterozygous for that allele
• Recessive allele


  The allele that only gets expressed when the organism is homozygous for that allele
• Genotype


  the two alleles present for a particular gene
• Phenotype


  The characteristics that an organism displays, which are determined by its genotype
• Characteristics are often determined by the interaction of multiple genes, not just a single gene
• Genes code for different forms of the same protein, which are called alleles
• If an organism is heterozygous for a trait, the dominant allele will be expressed and the recessive allele will not be expressed
• The only way to have a recessive trait expressed is if the organism is homozygous for the recessive allele
• Organisms with the same genotype may have different phenotypes, and organisms with different genotypes may have the same phenotype
• DNA


  Two strands wrapped around each other in a double helix
• Structure of DNA


  1. Nucleotides

  2. Complementary base pairing

  3. Gene coding for a protein
• Nucleotide


  Monomer unit of DNA, made up of a phosphate, sugar, and base
• DNA


  • Polymer made up of many nucleotides
  • Sugar phosphate backbone
  • Bases hold the two strands together through complementary base pairing
• Complementary bases


  A pairs with T, C pairs with G
• Genetic code


  Sequence of DNA bases
• Gene


  Particular sequence of bases that codes for a protein
• Proteins


  • Unique shape allows them to carry out specific functions
  • Main uses are in enzymes, hormones, and structural proteins
• Protein synthesis


  The process of making proteins
• Protein synthesis


  1. Transcription

  2. Translation
• Transcription


  The process of taking a single gene of DNA and copying it into a structure called mRNA
• Translation


  The process of taking the mRNA strand and using it to produce a protein
• Inside almost every cell is a nucleus that contains all the genetic material of that cell in the form of DNA
• The DNA is so big it can't leave the nucleus itself
• mRNA


  A copy of a single gene, shorter than DNA, single-stranded, and contains uracil instead of thymine
• Template strand


  The DNA strand that the RNA polymerase moves along to make the mRNA
• Codon


  A group of three bases that codes for a specific amino acid
• tRNA


  Molecules that bring the correct amino acid to the ribosome based on the mRNA codon