TALK WITH YOUR GROUP ABOUT ALL THE DIFFERENCES YOU SEE BETWEEN DNA AND RNA STRUCTURES…

Section 11.2 Summary – pages RNA structure differs from DNA structure in three ways. # 1 RNA is single stranded—it looks like one-half of a zipper— whereas DNA is double stranded.

Section 11.2 Summary – pages The sugar in RNA is ribose; REMEMBER: DNA’s sugar is deoxyribose. Ribose # 2

Section 11.2 Summary – pages Finally, both DNA and RNA can contain four nitrogenous bases, BUT RNA does not have Thymine. Thymine is replaced by a similar base called uracil (U). # 3 What do you notice instead?

Section 11.2 Summary – pages DNA provides mRNA with the instructions for making the proteins. RNA takes the copy of instructions to the ribosome The instructions are a code for how the protein should be assembled (amino acid by amino acid) DNA - boss with instructions RNA - workers that take the instructions from the boss to the site to carry out the job.

Chargaff’s Rule One of the puzzling facts about DNA was a curious relationship between its nucleotides. Erwin Chargaff (an American biochemist) had discovered that the percentages of guanine and cytosine bases are almost always equal in any sample of DNA.