Genes and the genetic code

• what protein is DNA wound around

  DNA molecules are wound around proteins known as histones to form a DNA-histone complex
• what is a chromatin

  when DNA-histone complexes coil further, helping pack the DNA into chromosomes
• what does each chromosome contain

  a single molecule of DNA
• what is DNA like in prokaryotic cells

  • store DNA in the cytoplasm
  • contain shorter, circular DNA molecules
  • do not associate the DNA with histones
  • DNA does not contain introns
• what is DNA like in eukaryotic cells

  • store DNA in the nucleus
  • contain long, linear DNA molecules
  • associate the DNA with histones
  • DNA contains introns
• where else do eukaryotic cells contain DNA

  in their mitochondria and chloroplasts
• what is the characteristics of the DNA in chloroplasts and mitochondria

  • short
  • circular
  • not associated with histones
• what is a gene

  a short section of DNA that codes for a polypeptide
• what is an exon

  sections of DNA that codes for amino acids
• what is an intron

  section of DNA that do not code for amino acids
• what is the definition of locus

  the specific position along a chromosome where each gene is located
• what is the definition of genome

  the complete set of genes within a cell
• what is the definition of proteome

  the full range of proteins that a cell is capable of producing
• what is the genetic code

  the sequence of bases that code for amino acids
• what is a triplet

  a sequence of three DNA bases that code for an amino acid
• what are the three feature of genetic code

  1. universal - each DNA triplet codes for the same amino acid in all organisms
  2. non-overlapping - each base in the DNA sequence is only read once
  3. degenerate - most amino acids are coded for by more than one triplet
• what is a codon

  a sequence of three mRNA bases that code for an amino acid