Which of the following best describes how the large and branched side chains are organized within a beta-sheet?   a. They are kept near each other.   b. They are kept far apart from each other.   c. They alternate every other residue.   d. They organize parallel to each other in consecutive polypeptide chains.

RNA was isolated from a tissue with a solution buffered at pH 12.  However, no RNA was obtained. Why? a.   The 5’ OH group of the ribose is protonated (positive charged) at pH 12 and reacts with the phosphorus atom to cleave the phosphodiester bond.   b.   The 5’ OH group of the ribose is deprotonated (negative charged) at pH 12 and reacts with the phosphorus atom to cleave the phosphodiester bond.   c.   The 2’ OH group of the ribose is deprotonated (negative charged) at pH 12 and reacts with the phosphorus atom to cleave the phosphodiester bond.   d.   The 2’ OH group of the ribose is protonated (positive charged) at pH 12 and reacts with the phosphorus atom to cleave the phosphodiester bond.

Which of the following is incorrect about the beta-sheet? a. The strands in anti-parallel beta-sheets are usually connected with turns b. Side chains are alternated above and below the sheet C. Parallel beta-sheets are less stable than the anti-parallel ones Od. It is stabilized by hydrophobic interactions between the side chains of nonpolar residues

You decide to play mad scientist and try to make an ‘RNA’ like molecule with a different Aldopentose. (remember ‘normal’ RNA uses ribose)  a. Which one would give you the best chance of making an RNA like molecule. Why would the others most definitely fail? (see image attached) b. Come up with a name for your new molecule

Which of the following disaccharide repeats is the most stable towards hydrolysis?   A. β-D-glcp-(1→4)-α-D-galp   B. α-D-glcp-(1→4)-α-D-galp   C. α-D-glcp-(1→2)-β-D-galp   D. β-D-glcp-(1→6)-α-D-galp

Draw both a parallel and an antiparallel beta-sheet using a ribbon diagram and use arrows to show the direction of the side chains.