Three DNA bases exist primarily as the keto tautomer because more hydrogen bonding interactions are possible in this form. However, it was originally thought that the bases existed as the enol tautomers because they appear to be more traditionally aromatic in this form. a. Draw the aromatic enol tautomer of cytosine. b. Draw the aromatic enol tautomer of guanine. c. Draw the aromatic enol tautomer of thymine.

Ascientist is examinin the cell is disrupted when she damages one specific type of macromolecule g the function of macromolecules in a cell she notices that movenent of large molecules into and out of

Two students are working together on an experiment that measures the effect of different liquid fertilizers on the thickness of plants’ stems. which is most likely to result in the greatest amount of error in their scientific experiment? a.one student measures the plant stem widths by using calipers. the other student measures the widths of the same plant stems again by using a different pair of calipers. b.one student measures the plant stem widths by using calipers. the other student types the measurements as they are taken into a computer spreadsheet. c.one student weighs liquids for the experiment by using a calibrated scale. the other student weighs liquids for the experiment by using a different calibrated scale.

According to theories of how life began, how did early organic molecules begin to separate from the outside world? a: specialized enzymes were required b: chains of amino acids created a barrier c: formation of microspheres or vesicles d: rna catalyzed the formation of membranes