What can carbon atoms do that makes them different from atoms of the five other common elements of life?
A. Form compounds with nitrogen and phosphorus
B. Form compounds with hydrogen and oxygen
C. Form polyatomic ions
D. Form four covalent bonds

Because of its structure the cell membrane is known as a phospholipid ? a.bilayer b.molecule c.fluid d.barrier

Which of the following is not one of the mechanisms of enzyme catalysis by which the substrate is converted to the product? a. changing substrate orientation b. changing substrate reactivity c. inducing strain in the substrate d. preventing an induced fit d. preventing an induced fit

According to the rna world hypothesis, rna acted as the genetic material and catalyzed reactions in ancient cells. what conclusion can you draw from this?               a.  this implies that dna and proteins aren't essential in cells today.    b.  this implies that rna can catalyze any chemical reaction that enzymes catalyze.    c.  this implies that if a cell has a problem with its dna, its rna can compensate for the damaged dna.    d.  this implies that dna and proteins evolved after rna.