DNA, Genes and Chromosomes

• Describe prokaryotic DNA.


  Short, circular, not associated with histone proteins.
• Describe eukaryotic DNA.


  Long, linear, associated with histone proteins.
• Name two organelles other than the nucleus that have DNA.

  Mitochondria and Chloroplasts.
• Describe the DNA found in Mitochondria.

  Short, circular, not associated with histone proteins.
• What is a gene?


  It is a base sequence of DNA that codes for a polypeptide or functional RNA.
• What is the position of a gene on a chromosome called?

  Locus.
• Most amino acids are coded for by more than one triplet code. What name is given to this?


  Degenerate code.
• The DNA is described as non-overlapping. What does this mean?


  The bases are read in triplets and then the next triplets are read.
• The DNA code is described as universal. What does this mean?


  The triplet codes for the same amino acid in all organisms.
• What is meant by the term exon?


  A sequence of DNA that codes for a polypeptide.
• What is meant by the term intron?


  A non-coding sequence that is found within a gene.
• What is a histone?


  Circular proteins that combine with DNA to make a chromosome.