chromosomes and dna

• what is a gene?

  a section of dna BASES which codes for a polypeptide and functional rna
• what is an allele?

  the different version of the same gene
• what is a chromosome?

  tightly coiled up DNA
• what is a locus?

  location of a particular gene
• what are homologous pairs?

  pairs of matching chromosomes which are exactly the same size, same gene but may have different alleles
• how is dna stored in a eukaryote

  • dna is stores inside chromosomes
  • chromosomes in a eukaryote are linear
  • dna is wound around proteins called histones to be tightly coiled
  • this complex of dna wrapped around a histone is called a nucleosome
• dna in prokaryotic cells

  • dna is shorter
  • dna is circular
  • they are not bound around histones ( not protein bound ) and are free floating in the cytoplasm
• how is dna in the mitochondria and cytoplasm similiar to prokaryotic dna?

  they are both short , they are both circular and both arent histone bound
• label this chromosome

  A) centromere