Pollard: Cell Biology, 3rd Edition
Chapter 2: Evolution of life on Earth
1. What is the best estimate of the number of genes in the first cell, the universal
About 600 genes is the minimum to carry out the biochemistry that we would today
count as being a viable self-renewing cell.
2. Other than carrying genetic information, what other property does RNA have that
makes it likely to have been the “spark” that kindled life?
a. It may have catalytic activity.
b. It is very stable in water.
c. It can form membranes in water.
d. It contains all the essential elements for life.
The catalytic activity of some RNAs allows it to self-replicate, self-cleave, and
catalyse formation of peptide bonds. Other catalytic activities may have contributed to
the essence of early life.
3. Which other material likely worked with RNA in the prebiotic world?
b. Biotite mica
c. Calcium carbonate
d. Montmorillonite clay
Interaction with clay allows RNA to fully unfold so that it can act as a template for
4. What is the name given to genes that occur in the same cell that have resulted from
duplication and mutation?