Biology Answers

DNA polymerase I (Pol I) of E. coli consists of three functional parts (domains): an N-terminal domain with 5 ´ to 3 ´ exonuclease activities required for removal of the RNA primer, a central domain responsible for 3 ´ to 5 ´ exonuclease proofreading, and a C-terminal domain with polymerase activity. Pol I is thought to simultaneously remove RNA primers and fill in the gaps that result. A group of proteins known as RNaseH also have 5 ´ to 3 ´ exonuclease activity and can thus remove RNA primers. However, they lack the other two functions observed for Pol I. Predict the ability of the following mutants to replicate DNA:
(1) a strain with a mutant gene encoding Pol I such that it no longer has polymerase activity (but retains both types of nuclease activities); [3]
(2) a strain without RNaseH proteins;

Describe and compare the metabolism of carbohydrates, lipids and proteins and in your
answer, explain the role of AT

Describe the principles behind five (5) laboratory techniques used in the isolation and
analysis of proteins

Give the full name, the 3-letter and 1-letter abbreviation of the following polypeptide.
Indicate the amino acid on the N- and the C-terminus of the structure.

Describe the structural characteristics that are common to all the amino acids that are
found in mammalian proteins and draw the structure of the tripeptide Tyr-Thr-Trp in the
ionic form that predominates at pH 7. Show all atoms (including hydrogens) as well as
any charges as necessary. Explain the general features of amino acid side chains and
the importance of associated non-covalent interactions.