EGG LAB POST!

In Science class we started learning our new topic, cells. After clarifying all of our doubts and question on the types of cell and their organelles, we moved on to a little more complex subject: Active and Passive transport of solutes and water between a cell and its environment. A week later though, we moved in to a more specific subject, the types of each transport, there is diffusion, facilitated diffusion and osmosis. Osmosis is just like diffusion, but only for water. Unfortunately this subject was indeed complex and specific so our teacher got us, the class, to do an experiment in which we used an egg membrane to represent an actual cell membrane and see how diffusion and osmosis really work.  

Predictions:

First we were put into groups of three members, we were then given six solutions to choose from (the eggs would later be dipped into the two chosen solutions): corn syrup, alcohol, distilled water, salty water (20% of salt), salty water (10% of salt) and tap water. My group chose distilled water and salty water (20% of salt). After all of this first process, we had to sit down in our groups and make predictions of what would happen to our eggs after being dipped into the chosen solutions for three days. My group came up with the following:

For the Distilled water we used our science knowledge to predict what would happen to the egg. Distilled water is pure water, not the one that we drink, pure water, with no minerals of solutes, because of this it makes it easier for the water to get inside the cell, causing it to fill up with water and consequently burst. Since we had this piece of information in our hands we predicted that since the egg acted like a cell, the water would go through it with no problem and eventually it would grow and consequently burst.

On the other hand, for the salty water we thought the opposite would happen, since the water has to balance between the inside of the cell, in this case the egg, and its environment. Since the water in which the egg was dipped in had salt, my group thought the water from inside the egg would come to the outside to dissolve the salt on the outside. Unfortunately this time we were wrong, the egg increased in size and by the touch of a sharp point, popped. We then sat down with each other to think of why this had happened, we then came to the following conclusion: There was even more solute inside the egg than in the salty water, so to balance both sides the water from outside the egg started to move inwards so that it could dissolve the solute inside the egg.

What we had to do:

On the first day our teacher did us the favour of putting the eggs in vinegar, we had to leave them there for 24 hours so that the egg shell would be easier to take off, this way we could work directly with the egg membrane (Be careful not to squish the egg too much, because the membrane is extremely sensible and may pop or burst). After this we had three days in a row to check both our eggs. In our groups we decided to name our eggs, but that is just a curiosity. Every day we had to follow exact steps and get the same measurements. After taking the egg out of the plastic cup which contained the liquid solution, we measured the amount left of liquid inside the cup with a graduated cylinder. Following that we took our eggs to the scale to see how much they were weighting. The third, but not last step was to measure the circumference of the eggs, for this we used a sting and a ruler. Last but not least we observed the egg and wrote down it´s physical characteristics. On the last day we were told to exchange results with other groups that had used the same liquid solutions as us. Later when we had all the information in hands we created graphs and tables to see our results, they are the ones that are below:

Appearance: 

 Day 1: The egg presents soft lines, the egg feels very soft and it is light.  The egg also presents an orange colour in some places, mostly top and bottom.

Day 2: The egg got both bigger and heavier, lost its orange colour, the lines got even more visible and still feels soft.

Day 3: The orange colour reappeared, got even bigger and heavier and now shows whiter spots.

Appearance:

Day 1: The egg had some whiter spots on top and bottom, presents a green spot, in some spots has an orange colour, also has soft line and feels soft.

Day 2: The whiter spots are still on the egg, the egg got both heavier and bigger, the green spot is gone, the orange spots became even more orange, the lines got even softer and harder to see, it feels soft and it is floating a little on the substance.

Day 3: Did not lose the whiter spots, got even larger and heavier, the lines almost disappeared and are really hard to see. 

Graph for Distilled Water:

Graph for Salty Water (20%):

We also took some pictures of how both our eggs looked after being opened, here are some of them followed by our observations:

Distilled Water:

Observations: After getting in contact with the sharp point the egg imidiately popped. Egg white looks like it was ripped to pieces, it also looks as if it were dissolved. There is a lot of water inside the egg. Egg yolk was not affected and still had its normal texture.

Salty Water (20%):

Observation:  Egg popped after coming in contact with the sharp point or instrument.Egg Yolk grew in size, egg white also looks as if it were dissolved. The egg yolk feels as if it is more solid than  liquid or as it is before.
 Fun picture of our group working:

Working hard to finish all the required steps on time, write results down and share them with each other!

Evaluating Team Work:

In my group everyone worked very hard and did all of their jobs. We distributed the tasks and did the observations and the appearances all together. It was a lot of fun working in this group because no one did more work than anyone else. We also always kept focus and did not fall into temptation of talking about other things. Once we were done we talked about each other’s ideas for the table and checked results. It was a great success and we did not encounter any difficulties.

What I learned + Diffusion and Osmosis in living things:

This experiment really helped me understand what diffusion, facilitated diffusion and osmosis are, how they work and what they are. An example of diffusion in a living thing is of the oxygen and carbon dioxide in our lungs and capillaries. When we breath in we bring oxygen into our lungs, this oxygen soon starts diffusing into the capillaries and so does the carbon dioxide, but on the opposite direction. We then breathe out the carbon dioxide. This happens every time we breathe in and out. I found it very interesting because I never saw the whole process of breathing in a so complex and detailed way and this example also helped me learn and understand the process of diffusion better.

Summary:

Our group started off by writing predictions, we chose to work with Distilled water and salty water (20%). We thought the Distilled water would increase the egg, since it is pure water, which no minerals in it, so the process of osmosis will happen faster. It sure did! Our prediction was indeed supported by our data, first of all the volume of water on the cup decreased rapidly and in great number. This shows that the amount of water inside the egg increased, both the circumference and the mass also did. The circumference increased due to the fact that the egg got wider because of the amount of water inside. The same reason goes for the mass, the water inside the egg made it heavier.  Some things that could have changed the results were the facts that first, some water spilled and second the tip of the sting to measure the circumference was ripping apart and could affect the measure with the ruler. A way to make sure this does not happen is use a different and new sting everyday and for the water be careful or even add a millimeter to the amount of water inside the beaker, which would not be precise either, but could be a way to fix it.

For Salty water we had the prediction that because of the amount of salt in the water the egg would lose water, but this time we were wrong, the egg increased in size, the volume in the cup decreased and both the circumference and the mass of the egg increased, we were surprised but came to a conclusion of why our predictions were not right. The water concentration has to be balanced between both sides, inside and outside the cell (in this case the egg), we would think that since the salt level was big inside the water, the water inside the egg would go to the cup, but it was actually the opposite situation. This happened because there were more solutes inside of the egg so the water went inside the egg instead of leaving it. What we could change would be the same things as for the first one. 

Concluding:
This experiment really helped me understand all that we have been learning in science class since we started our subject of cells. I also enjoyed working in this experiment because it was fun and different from anything you would expect to do in a lab. I really loved it and would adore doing it all over again, but this time with different liquid solutions. So, if you are having trouble understanding Diffusion, Facilitated Diffusion and specially osmosis you should ask your teacher to do this experiment in class, hoped you have enjoyed this blog post, see you soon!

Why am I, the DNA important inside a cell?

In this week´s science class we were divided into three groups of several people, after this each of us were given a organelle to represent inside the cell, for example, I got to be the DNA of a cell for one short day. After we were each given a role to play, all the groups were put into the same complicated situation: All the organelles were inside a boat and due to “overweight” the boat captain based on ours one minute speeches had to decide who would be through out of the boat and who would stay.

Since I was given the DNA, I first decided to do some research about it and which other organelles it “worked with”. I found out many useful information, read it all and put the main and most important points into my speech, which follows:

I am important inside the cell since I contain all the genetic information, in other words when two cells reproduce the DNA molecule divides and the new cell will have a mixture of both DNA´s. I, the DNA define “who” the cell is, it´s genetic code, for instance: colour, size, format or shape and others. So basically the DNA is what makes the cell what it is. The genetic information made by me is transported all over the cell by the RNA. I also command the protein production and the RNA who transports information to the Ribosome, who is the producer of proteins and only produces the protein according to the information sent by me.