Small World Biology

How Cells Do What They Do

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The story behind this site.

I've always been amazed at life at the cellular level. Inside every one of your 50 trillion or so cells, molecular machines are performing complex tasks with incredible precision. Yet nobody is running the show. All the activities that take place arise from inanimate matter (mainly molecules... which are not alive) randomly crashing around. How can such precision arise from randomness?

In this blog, I attempt to paint a detailed picture of the cellular world for non-scientists that illustrates this seeming contradiction. I'll be presenting the cell's activities at a deeper level than is typically presented to the public. The content of this blog will often be at or above the level of a graduate school course.

In order to go deep, though, we can't go too wide. So, after covering some foundational molecular biology, our focus will be on just one of the cell's activities: the process by which it copies, or replicates, its genome with high accuracy prior to cell division. It's a massive task, and the steps the cell goes through to accomplish it are mind boggling.

Enjoy! And please share your thoughts. I'd like to get better at writing about this topic so I appreciate your feedback.

The Fix-It Crew II

A DNA lesion is any change to a DNA molecule that disrupts its normal chemical structure. This excludes DNA polymerase so-called " errors." In the case of errors, while there is a non-complementary pair of nucleotides in the double helix, the chemical structure of the nucleotide molecules remains intact. In this post, we'll discuss the the DNA repair pathways that correct the vast majority of DNA lesions. These include ribonucleotide excision repair (RER) , base excision rep

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The Fix-It Crew I

Life can't exist without the high fidelity transmission of genetic information from parent cell to daughter cell. DNA polymerases plays a big role in accomplishing this. DNA polymerases delta and epsilon only make an error (that is, attach a non-complementary nucleotide to a growing chain) once every 100,000 to 1 million nucleotide additions. But this is too many. They'll need to be fixed via a back-up system that we'll soon be discussing. In addition, the human genome--eve

lscole

Winding Problems

As the CMG helicase moves along the double helix separating it into a leading and a lagging strand, it creates what is often referred to...

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