DNA structure 2

• what determines biological sex?


  sex chromosomes= x , y
• Heredity ( inheritance) is the passing on of characteristics from one generation to another.
• DNA = deoxyribonucleic acid, a molecule that contains the genetic information of an organism
• what are the two types of nucleic acids?


  DNA and RNA
• Nucleic acids are large molecules that were discovered in cell nucleus
• what holds together the bases between DNA strands?

  Hydrogen bonds
• Which elements do nuclei acids contain?

  • The elements carbon hydrogen , oxygen , nitrogen and phosphorous.
• What are the monomers in a nuclei acid?

  nucleotides
• which chemical bonds that hold together the sugar- phosphate backbone?

  by phoshodiester
• What type of chemical reaction joins together the nucleotides?

  condensation reactions
• Why is DNA describe as a double helix?

  because it is made up of two strands that are twisted together
• What is meant by complementary base pairing?

  Matching of nitrogenous bases in DNA: A-T, C-G.
• why does DNA always have equal amounts of cytosine and guanine?

  Because of the complementary base pairing