Transcription of Genes

I'm going to try something a bit new:  I'll make the videos that usually accompany my genetics class with copyright-free images and provide the theory and context of genetics in a way that I can post online outside of our course management system.

So here's the first-ever fully public presentation of "Transcription", which I'll do in two parts!
Part 1 - Overview

Part 2 - A little more detail

How cool is that structure?

Today in class we were to go over the structure of DNA.  The structure is intimately linked to its function, so the base-pairing aspect is HUGE.  The fact that a string of bases on one DNA molecule can dictate the order of nucleotides on the partner molecule is the only thing that allows information to be transferred from cell-to-cell during division, and by extension from parents to offspring generationally.

To show the awesome beauty of the molecule I showed a great site in class: http://www.umass.edu/molvis/tutorials/dna/ This was put together by Dr. Eric Martz and he lets people use it for free.  I think being able to rotate and move the molecule, to zoom in, isolate nucleotide pairs, and all the features here are a great way to really appreciate how DNA works!

I encourage you to go to the site yourself and see what you can see.  The link I gave above is the hands-on part.  I thought I'd share with you my thoughts about this activity in a little movie (below).

Have fun!

Draw and number a pentose

Here's an important skill:  you should be able to draw and number a pentose sugar.  The bases are a bit harder to draw - they have all kinds of functional groups and there are two fairly different structures (purines and pyrimidines).

You should for sure recognize a purine and know there are two types in nucleic acids (it's the double-ring structure and consists of A or G).  You should also recognize pyrimidines and know which nucleotides fall into this category (single-ring with C and either T or U, depending on whether it's DNA or RNA).

Each nucleotide has the nitrogenous base attached to the 1' carbon of the pentose sugar.  And you number the carbons sequentially from that starting point.

So here:  I'll leave you with a challenge.  Draw a pentose sugar attached to a purine (don't sweat the purine details too much... just make it distinguishable from a pyrimidine).  Be able to alter your figure to depict a ribose, a deoxyribose, and that really strange entity used for Sanger sequencing: a dideoxyribose.  If you can, depict where the phosphates fit on the structure, and then number the pentose carbons according to standard conventions.

Here's how I'd do it  (quick'n'dirty 3 minute video):