Agar Cube Lab

In terms of maximizing diffusion the 1cm x 1cm x 1cm cube worked the best. This size was the most effective because it had the most surface area in comparison to volume at 6:1. This factor is important because it allowed the cube to be the most exposed for its size and diffuse the quickest.

Cells don’t grow to be very large because the larger they grow the greater their volume becomes which creates a worse ratio of surface area to volume. Whereas with 3 cubes with surface 3:1, 5:2, and 4:1 the cube with the surface area of 4:1 would diffuse the best. I know this because in our lab the cube with the 6:1 ratio worked best where as the 3:1 ratio was second best and the 2:1 ratio was the worst, so higher surface area : lower volume is the best for diffusion.

Our bodies adapt this by making our cells have greater surface area while trying to keep volume low, this is done by cell division, so that every time a cell grows in volume that is inefficient it divides. Bacteria works in the same way and therefore could never grow to be the size of a small fish. Because cells like these rely on cell division to survive and reproduce.

The advantages of being multi cellular is that there isn’t a limitation placed on growth, lifespans are longer as cells can reproduce while single cellular organisms can die.



Protein Synthesis

mRNA differs from DNA because it is single stranded, has a ribose sugar oppose to a deoxyribose and instead of thymine it has the nucleotide Uracil. It is easy to see some of the differences in the picture below.

The process of transcription begins the DNA unwinding into single strands with the helicase.

Once the DNA is single stranded the polymerase comes in and makes a complimentary base paired RNA strand. A-U, C-G. Therefore copying the correct nucleotides onto the RNA strand. While also creating hydrogenbonds between the RNA and DNA.

Once this is finished the RNA disconnects from the DNA and the DNA comes back together. So that there is a RNA strand with the correct printed nucleotides and the DNA double helix.

Overall this wasnt as effective as the last few pipe cleaner labs because I felt that this one was a little more confusing and didn’t show the processes as well.

Protein synthesis begins with Initiation. Initiation is when the mRNA is read by the ribosome P group and the tRNA translates it into an amino acid.

Afterwards is elongation. Elongation is when the mRNA continues to move through the ribosome and the A group reads the next codon and the tRNA brings in another amino acid.

After this step the tRNA leaves the P site and the amino acid moves onto the tRNA in the A site.

Once this occurs the tRNA moves over to the p-site to continue growing the chain.

Once the chain has reached the stop codon then termination occurs and the chain ends.

Afterwards the ribosome lets go of the mRNA and tRNA lets go of the polypeptide.

Overall, I think activity was good at explaining the process of protein synthesis but it was difficult the instructions were hard to grasp, but once I understood it, it helped me understand protein synthesis.

DNA and Protein Synthesis

  1. DNA Structure is a sugar phosphate backbone that has nucleotides on it. These nucleotides have complimentary base pairings Adenine – Thymine, Thymine – Adenine, Guanine – Cytosine, Cytosine – Guanine. How ever these base pairs are on an anti-parallel strand that connects with hydrogen bonds. As you can see in the first photo it has the first backbone with the first set of Nucleotides on it. Then in the second photo when connected to the other backbone the nucleotides are complimentary base pairs. If read then this 2nd backbone would be read upside down because it is anti parallel.
  2. This activity helps model the structure of DNA because the different colors of everything allow you to understand the different parts of DNA. Having the pink beads be phosphate with the blue being sugar helped me understand the Sugar-Phosphate backbone a lot more. I think to make this more useful bigger supplies could be used so that they could potentially be labeled to really make everything stick.
  3. DNA replication occurs prior to cell division. The first step is the unzipping and unwinding of the DNA with the DNA Helicase. The second step is the base pairing where the DNA Polymerase will read the single strand and build a second one with complimentary base pairings, in this step the 5′ – 3′ strand is the leading as the polymerase works in the same direction is the helicase. Whereas the 3′-5′ strand is lagging as the polymerase works in the opposite direction of the helicase so it has to go back and get the next strand. The 3rd step is the Ligase gluing all of the lagging strands together to create a full DNA strand. These pictures show case this. With the first one being the helicase unwinding, the 2nd being the polymerase rebuilding the new DNA back bone and the 3rd being the ligase glueing the lagging strands

    This activity was well suited to show the understanding of DNA replication. It helped me understand how the different enzymes work to unwind and rebuild. It wasn’t great to show the lagging and leading strands because of the way the pipecleaners were long and we were unable to cut them so we had to fold them. Overall thisĀ  was a good way to learn about DNA replication