An organism is discovered with a DNA polymerase that replicates DNA in the 3' to 5' direction, and examination of progeny cells showed DNA was nearly identical to the original with few errors, suggesting this polymerase may have a proofreading mechanism like eukaryotes. If not, a necessary characteristic of this polymerase or organism would be what?

1. Cell and Molecular Biology, Assignment 4
A newly discovered organism is found have an unusual DNA
polymerase that replicates its DNA by joining nucleotides together in
the 3’ to 5’ direction. Examination of the DNA resulting from numerous
rounds of cell division showed that the DNA of the daughter cells was
almost exactly identical to the DNA of the original cell with hardly any
errors. Could this DNA polymerase have a proofreading mechanism like
the DNA polymerase in eukaryotic cells? Why? If not, what would you
hypothesize might a necessary characteristic of this DNA polymerase
or of this organism?

2. To see if DNA polymerase can catalyze a reaction between a 2’ hydroxyl
and a 5’ phosphate, Zufio decides to synthesize a deoxycytosine
triphosphate with the hydroxyl in the 2’ position instead of the 3’
position, which he calls 2’-dCTP for short.
A. Draw the skeletal structure of 2’-dCTP.
Zufio then adds 2’-dCTP into a DNA replication reaction at a
concentration that is 10% that of dCTP (the nucleoside triphosphate
normally used in DNA replication).
B. If DNA polymerase cannot catalyze the reaction between a 2’
hydroxyl and a 5’ phosphate, what results would Zufio expect to see
from the DNA replication reaction?
C. If DNA polymerase can catalyze the reaction between a 2’ hydroxyl
and a 5’ phosphate, would the newly synthesized strands of DNA be like
ordinary DNA strands? Would they form double helices as DNA
normally does? (Hint: consider figures 5-6b and 6-10)

3. Dolira finds a bacterium that has a mutant tRNA synthetase that
roughly 50% of the time attaches acetic acid (shown on the left) to a
tRNA instead of glycine (right).
What effect, if any, will this have on protein synthesis in this bacterium?

4. Question 5-8 from Essential Cell Biology
A. A macromolecule isolated from an extraterrestrial source
superficially resembles DNA but upon closer analysis reveals quite
different base structures. Bases V, W, X, and Y (shown below to the left)
have replaced bases A, T, G, and C (shown below to the right). Look at
these structures closely. could these DNA-like molecules have been
derived from a living organism that uses principles of genetic
inheritance similar to those used by cells on earth? If so, what can you
say about its properties?
B. Simply judged by their potential for hydrogen-bonding, could any of
these extraterrestrial bases replace terrestrial A, T, G, or C in terrestrial
DNA? Explain your answers.

5. You are working for a nonprofit organization combatting malaria. One of
your biomedical contacts send you the paper with the following
title: Hemoglobins S and C Interfere with Actin Remodeling in Plasmodium
falciparum −Infected Erythrocytes
Faced with many work-related responsibilities, your time is limited, but
you need to understand the crux of this latest research on malaria and
communicate this to your peers who have some biology background
which is not as rigorous as yours. What do you tell them based on your
reading of the abstract and a scan-through of the paper? What
resources will you use and what basic MCB knowledge must you make
sure you present your peers so they can understand what you
understand from the paper?