Module 1: DNA Replication Paperclip Activity

This activity is a great little demonstration of how DNA replicates! This is a very simplified version of DNA replication, but it's a great way to visualize the basics! This demonstration is supposed to be done with colored paperclips, but I didn't have any on hand. So I got a little creative, and used some colored sticky note tabs instead! I really like the way this turned out, because I think these "tabs" look a little more like DNA than the paperclips would've!

Each of these color tabs represent a base! This is one strand of the DNA, and it reads "AAGCTTATGG".

Here's both strands! Notice how Adenine (blue) always pairs with Thymine (orange), and Guanine (pink) always pairs with Cytosine (purple).

To replicate itself, the DNA unzips, and creates a replication fork, where new compleentary bases can be added in to make a new strand.

Using our base-pairing rules, we can add more bases in to create matching DNA strands!

We just keep going along, adding matchin base pairs, until we have two new strands of DNA! Ta-da!

(1) Our replication is complete, and we have an identical copy of our original strand! They match up perfectly!

(2) If we wanted to copy these strands, to make four strands total, we would go about it in the exact same way! Each of these strands would unzip to form a replication fork, and base pairs would be added to the inside in order to create the new complementary strands.

(3) The DNA replication process is really good at making sure that we get an exact copy each time. Part of what makes these copies always identical is the base pairing rules. A always has to go with T, and C always has to go with G. There are also some other steps that help us make sure we have the same copy each time, that we didn't demonstrate in this model. One of these is that the DNA gets proof-read for any mistakes that do happen! If a mistake is made where the wrong base pairs are matched, the wrong base pair gets cut out, and the correct one gets added in.

(4) Even though there are steps in place to make sure all errors are caught, the proof reading isn't perfet. Some mistakes get through! These changes in the code are called mutations. So lets say we had a mutation so that our two different strands had an incorrect base pair, like this:

ACGCTTATGG

TTCGAATACC

The 2nd set is incorrectly matched - C and T aren't supposed to go together! What would happen if we replicated this strand? It actually turns out that this mistake is carried over to one of the new DNA strands when it's replicated! The mistake gets copies into the new DNA.

(5) Look at these two strands that were formed from copying our incorrect base pair - these strands don't match anymore!

(6) There are many reasons that mutations occur. Some can be caused by carcinogens - or cancer causing agents. These also include things like radiation. This is why doctos are careful to limit how many xrays you get, and use special material to cover up your reproductive system - we wouldn't want any mutations in the egg or sperm cells and being based on to your future children. Mutations can have a huge effect when they're in our sex cells!

Some mutations have no effect at all on the offspring. Others can be deadly, and can cause a miscarriage of a fertilized egg, embryo, or fetus. In the middle, we'll see some mutations that create harmless changes, like changing your eye color, hair color, or skin color. Other mutations lead to certain genetic disorder, like Cystic Fibrosis, for example. It all depends on where these mutations occur!