dna

• The DNA molecule consists of two strands twisted around one another, forming a double helix structure.
• DNA is the genetic material that contains instructions to make proteins.
• Adenine (A) always pairs with thymine (T), while cytosine (C) always pairs with guanine (G).
• The sugar-phosphate backbone holds the bases together and provides structural support.
• The sugar-phosphate backbone holds the bases together by hydrogen bonding.
• what are dna bases?

  Adenine, Thymine, Guanine, Cytosine
• what is the structure of dna?

  Double helix
• how are dna strands held together?

  Hydrogen bonds
• describe the shape of a dna molecule

  double helix
• describe a hydrogen bond

  weak attraction between one slightly negative and one slightly positive base.
• why do only c+g and a+t join together?

  because c+g is held together by 3 hydrogen bonds and a+t is held together by 2 hydrogen bonds.
• what makes genes slightly different from person to person?

  because the order of bases differs from person to person
• if you are arrested, why would they take a sample of your cells?

  DNA analysis. the order of bases in a gene contains coded instructions for a protein, but we all have slight differences in our genes, caused by slightly different orders of bases in our dna. this is what allows scientists to match dna from cells to specific people.
• describe how complementary base pairs help to form the structure of dna

  Within a molecule of DNA, pairs of bases are chemically bonded together by hydrogen bonds. These bonds hold the two strands of the molecule together. 
• what part of the dna molecule contain instructions for making chromosome packaging proteins?

  genes.
• what is a nucleotide

  .

  
• the nuclei of cells contain very long molecules of dna. each molecule is tightly coiled and packaged up with proteins to form chromosomes
• dna is packaged up tightly with proteins in a chromosome
• each base is attatched to a sugar and each sugar is attatched to a phosphate group
• the sugars and phosphate groups form the backbones of the dna strands. and are joined in a chain, this is what makes dna a polymer.
• dna is a polymer
• dna is a molecule