(Unit 1.1) Structure of DNA

• What is the structure of DNA described in the study material?


  DNA has a double stranded helix structure.
• What are the four bases that make up DNA?

  The four bases are adenine, thymine, cytosine, and guanine.
• What are the components of a nucleotide in DNA?

  • A phosphate molecule
  • A deoxyribose sugar molecule
  • A nitrogenous base (adenine, thymine, cytosine, or guanine)
• How are nucleotides in DNA structured?

  Nucleotides are joined together by a sugar-phosphate backbone.
• What is the orientation of the two strands in the DNA double helix?

  The two strands run in opposite directions, known as an anti-parallel structure.
• What type of bonds hold the complementary base pairs together in DNA?

  Hydrogen bonds.
• What is the significance of the sugar-phosphate backbone in DNA?

  It provides structural support and stability to the DNA molecule.
• What are the two types of bonds mentioned in the structure of DNA?

  Sugar-phosphate bonds and hydrogen bonds.
• Where can nucleotides be added in a DNA strand?

  Nucleotides can only be added at the 3' end of the strand.
• What are the key differences between prokaryotic and eukaryotic cells?

  • Prokaryotes:
  • No membrane-bound organelles
  • Singular circular chromosome
  • Smaller circular plasmids
  • Eukaryotes:
  • Membrane-bound organelles including a nucleus
  • Linear chromosomes
  • Circular chromosomes in mitochondria and chloroplasts
• What is a unique feature of prokaryotic cells?

  They do not have a nucleus.
• What is the role of histones in DNA organization?

  Histones help package and condense DNA into a compact structure.
• How is DNA organized within the nucleus?

  • DNA is tightly coiled and packaged with histones.
  • This organization allows DNA to fit within the small space of the nucleus.
• What is the significance of yeast in the context of eukaryotic cells?

  Some forms of yeast contain plasmids, despite being eukaryotic.