DNA structure & Replication

    Cards (23)

    • What does DNA stand for?
      De-oxy ribo nucleic acid
    • Where is DNA found in eukaryotic cells?
      Within the nucleus
    • Where is DNA located in prokaryotic cells?
      In the cytoplasm
    • Why is DNA considered an important molecule?
      It carries genetic information
    • What type of information does DNA store?
      Genetic information for proteins
    • How is DNA organized in eukaryotic cells?
      Into chromosomes
    • What is a chromosome made of?
      Protein and a single DNA molecule
    • When do chromosomes become visible in cells?
      When cells are dividing
    • What is chromatin?
      Partially coiled DNA not visible under microscope
    • What are the differences between eukaryotic and prokaryotic DNA?
      • Eukaryotic DNA:
      • Has a nucleus
      • Linear DNA
      • Larger DNA
      • Prokaryotic DNA:
      • Doesn't have a nucleus
      • Circular DNA
      • Shorter DNA
    • What type of DNA do mitochondria and chloroplasts contain?
      Shorter, circular DNA
    • What are the components of a nucleotide?
      Phosphate group, deoxyribose sugar, nitrogen base
    • What type of structure does a DNA molecule have?
      Double helix structure
    • What type of bond forms the sugar-phosphate backbone of DNA?
      Phosphodiester bond
    • What is the significance of complementary base pairing in DNA?
      Ensures accurate DNA replication
    • What elements are found in DNA?
      C, H, O, N, P
    • How does DNA structure relate to its function?
      • Double stranded: Stable molecule, unchanged sequence
      • Helix/coiled: Compact for fitting in nucleus
      • Long molecules: Stores lots of genetic information
      • Complementary base pairing: Accurate replication
      • Many hydrogen bonds: Stability
      • Weak individual bonds: Allows replication and transcription
    • What is semi-conservative replication of DNA?
      Each new DNA keeps one original strand
    • What are the stages of semi-conservative replication of DNA?
      1. Parent DNA strands separate
      2. New strands made using templates
      3. New DNA molecules identical to parent
      4. Ensures genetic continuity in daughter cells
    • What enzyme unwinds DNA during replication?
      DNA helicase
    • What does DNA polymerase do during replication?
      Joins sugar-phosphate backbones of new strands
    • In which direction can DNA polymerase move along a strand?
      Only in one direction
    • What evidence supports semi-conservative replication of DNA?
      1. Bacteria cultured in ¹⁵N medium
      2. DNA extracted and centrifuged
      3. Transferred to ¹⁴N medium for division
      4. DNA extracted and centrifuged again
      5. Allowed another division in ¹⁴N medium
      6. DNA extracted and centrifuged
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