Cell Tour | By Sarah Behselich
For the following project, students were to act as a mentor to a young organelle new to a cell and give them a tour. The tour highlights the locations of the other organelles and their functions. Sarah Behselich chose to create a dialogue which is both entertaining to read and educational.
“Hello, and welcome to the animal cell tour! My name is nucleus and I will be your guide this evening! Please refrain from touching any of the cell structures as we walk by, they are very hard at work. As we tour the cell, I will be giving a short, yet detailed explanation of each structure. Please feel free to ask any questions as we make our way through. Let’s get started, shall we? To start of the tour we are going to head into the cell. As we are entering if you just look around you, you will see the cell membrane. Does anyone know what else it is called? How about you in the back there.”
“It’s also known as the plasma membrane.”
“That is correct! Now it functions as a selective barrier, which means it allows some things in but not others. It is made up of lipids, and has many different types of proteins. If you will follow me a bit further you will notices around us the cytoplasm and the cytoskeleton. Cytoplasm is the fluid that surrounds all organelles and fills up the cell. Does anyone know what it is made up of? You there in front!”
“It is made of water, dissolved salts, ions and organic molecules!”
“Righto! You sure know your stuff! The cytoskeleton is the network of fibers that run all through the cell. It holds the shape of the cell, hold most of the organelles in place, and directs their movements. Pretty handy, I would say! Let’s continue on, and view the ribosomes! What happens here?”
“Protein synthesis!, which means they take the cell’s DNA and construct large protein molecules. They then release the proteins to the needed areas!”
“Well said! These handy organelles, are considered the smallest of them all! There are two different kinds within a cell. Free and bound ribosomes. Free ribosomes are found all throughout the cytoplasm. Bound ribosomes stick with their friend, the rough endoplasmic reticulum. Moving on from those, let’s check out their friend endoplasmic reticulum. Could you believe that these membranes account for more than half of the total membrane found in the cell?! It is also divided into two different ER.
The first is the rough ER. It is called rough because the surface is covered by small ribosomes. The membrane of the rough ER is responsible for keeping the proteins made by the ribosomes separate from the rest of the cell. Bits of the membrane form sealed sacks called transport vesicles, which carry the proteins to the golgi apparatus. Now smooth ER has no ribosomes, and its function depends on what?”
“The specialization of the cell that it is located in!”
“Right again, you guys are great! Some metabolic processes it participates in are lipid construction, carbohydrate deconstruction, and substance detoxification. While we are here, let’s take a look at my personal favorite! The nucleus! This large organelle contains most of the cell’s genetic information. Inside you will find chromosomes that are quite tangled when the nucleus isn’t dividing. Those tangles are call the chromatin, and along with those is the nucleolus. The nucleolus is needed for the synthesis of ribosomes. Depending on stage and species some can have a more than one nucleolus! If you look closely you will see membrane enclosed sacs that are called vacuoles! These are responsible for a variety of storage functions. Some store food and nutrients, others water, minerals, and ions. They sure do come in handy for our cell!
Come on a bit further over this way and we will take a look at the wonders of the lysosomes! Can anyone tell me what a lysosome is?”
“Yes, it is a membrane sac filled with enzymes!”
“Very good, my friend! These enzymes digest large molecules into smaller ones to be used. Both the lysosomes and the enzymes are made in the rough endoplasmic reticulum, and then moved to the golgi apparatus for even more processing! A cell has many different lysosomes, all with different enzymes! They provide the perfect acidic home for the enzymes to digest in peace without disturbing the other molecules of the cell. Please follow me to our last organelle, and probably the most well know! Anyone want to take a guess?”
“The mitochondria, which is also known as the powerhouse of the cell?”
“Absolutely! Now the mitochondria is enclosed in not one, but two layers of membrane! The inner layer being called cristae. These folds are both very important, because they provide the needed surface area for the important reactions to occur.
“Excuse me! Why is it called the powerhouse of the cell?”
“Excellent question! You see the mitochondria is like the cell’s digestive system. It takes in nutrients and breaks it down, and these chemical reactions release the energy used to power the cell! One important reaction that it is responsible for is cellular respiration. Can anyone tell me what that entails?”
“That is a process that uses molecules to release different forms of energy to be used by the cell!”
“Right you are! Why am I even teaching? Just kidding! Almost all eukaryotic cells have mitochondria, and can have up to thousands of the little buggers! They are very important for the survival of a cell, because if the cell isn’t getting enough energy they can reproduce to create more. Now if you will follow me out of the exit; that will conclude our tour of the animal cell! Does anyone have any extra questions before we head out fully?
“How does an animal cell differ from a plant cell?”
“Great question! While both cells are very similar, a plant cell contain two extra organelles. The cell wall, and the chloroplasts. The cell wall provides extra protection for a plant cell, maintains the cell shape, and prevents excess intake or loss of water! Chloroplasts are responsible for converting energy from sunlight into chemical energy for the cell to use. Which is also known as photosynthesis! Any other questions? No?
Well, with that I bring our tour to a close. Thank you for joining me on this exciting journey, and being such a great audience! If you will just continue to the right exit, you can join the line for the plant cell tour or continue on to other activities.
Goodbye everyone!”
