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Flashcards · Biology · What Happens in Cells

The Structure of DNA

17 cards

  1. What is DNA?

    A polymer that stores the genetic information of a cell.

  2. What is a polymer?

    A large molecule made of many smaller units joined together.

  3. How many strands does DNA have?

    Two.

  4. What shape is a DNA molecule?

    A double helix, a twisted ladder.

  5. What joins the two strands of DNA?

    Pairs of bases.

  6. What is a gene?

    A section of DNA that codes for a protein.

  7. What is a chromosome?

    A long, coiled DNA molecule that carries many genes.

  8. What is the genome?

    All of the genetic material of an organism.

  9. Where is DNA found in a plant or animal cell?

    In the nucleus, in the chromosomes.

  10. Where is DNA found in a bacterial cell?

    As a loop in the cytoplasm, and also in plasmids.

  11. What is a plasmid?

    A small ring of DNA found in bacterial cells.

  12. What do genes code for?

    Proteins.

  13. Why is detergent added when extracting DNA?

    It breaks down the cell membranes.

  14. Why is cold ethanol added when extracting DNA?

    DNA is not soluble in it, so it comes out of the solution as a white solid.

  15. Who published the double helix model, and when?

    Watson and Crick in 1953.

  16. A DNA double helix with a pointer marked X to one strand. Name the part marked X.

    A strand. Each strand is a polymer, and two strands form the double helix.

  17. A DNA double helix with a bracket along part of it and no labels. Label the parts of this DNA molecule. The same DNA molecule with every part labelled.

    Two strands, joined by pairs of bases, form a double helix. The bracket marks a gene, a section of DNA that codes for one protein.