Chapter 5 - DNA AND CHROMOSOMES

Chapter 5 - DNA AND CHROMOSOMESUsing terms from the list below, fill in the blanks in the following brief description of the experiment with Streptococcus pneumoniae that identified which biological molecule carries heritable genetic information. Some terms may be used more than once. Cell-free extracts from S strain cells of S. pneumoniae were fractionated to __________________ DNA, RNA, protein, and other cell components. Each fraction was then mixed with __________________ cells of S. pneumoniae. Its ability to change these into cells with __________________ properties resembling the __________________ cells was tested by injecting the mixture into mice. Only the fraction containing __________________ was able to __________________ the __________________ cells to __________________ (or __________________ ) cells that could kill mice. carbohydrate lipid R strain DNA nonpathogenic RNA identify pathogenic S strain label purify transform The Structure and Function of DNA 5-2 In a DNA double helix (a) the two DNA strands are identical. (b) purines pair with purines. (c) thymine pairs with cytosine. (d) the two DNA strands run antiparallel. (e) the nucleotides are ribonucleotides. 70 5-3 On the diagram of a small portion of a DNA molecule in Figure Q5-3, match the labels below to the numbered label lines. Figure Q5-3 (a) Base (b) Sugar (c) Phosphate (d) Hydrogen bond (e) 5 end (f) 3 end 5-4 The structures of the four bases in DNA are given in Figure Q5-4. Figure Q5-4 A. Which are purines and which are pyrimidines? B. Which bases pair with each other in double-stranded DNA?