Week 2 Lecture Prep: r/w/e dna

##Pre Reading and Question Answer Exercise-Part of Week 2 Lecture Prep

Q.1:Nature’s machinery for copying DNA is called polymerase. What is the error rate of polymerase? How does this compare to the length of the human genome. How does biology deal with that discrepancy?

Ans:The error rate of polymerase is 10-4 as stated in bio numbers polymerase.The human genome has 3 billion base pairs. biology resolves this high error rate through multilayeres proof reading systems suvh as exonuclyotoc proofreading , post replcation and proofreading in the trans. Reference: website.https://bionumbers.hms.harvard.edu/bionumber.aspx?s=n&v=2&id=105476

Q.2: How many different ways are there to code (DNA nucleotide code) for an average human protein? In practice what are some of the reasons that all of these different codes don’t work to code for the protein of interest?

Ans: there are 100 power 100 possibilities but few works because of the efficiency, stability and folding kinetics.

Q.3:What’s the most commonly used method for oligo synthesis currently?

Ans:Solid phase phosphoramidite it remains gold standard because of high coupling efficiency.

Q.4: Why is it difficult to make oligos longer than 200nt via direct synthesis?

Ans: This is because of the accumulation of impurites and difficulty to sepeatey of full length sequences of vast majority of truncated failed products.

Q.5:Why can’t you make a 2000bp gene via direct oligo synthesis? Ans:This is beacuse of impurties and lack of efficiency and chemical reactions have more error rates.

Q.6:[Using Google & Prof. Church’s slide #4] What are the 10 essential amino acids in all animals and how does this affect your view of the “Lysine Contingency”?

Ans:Histidine, Isoleucine,Leucine,Lysine,Methionine,Phenylalanine,Threonine,Tryptophan,Valine,Arginine (conditionally essential for many, but essential for growth/specialized needs). As far as theory its doesn’t make them any different because any vertabre cant synthesie the lysine.