Jun 29, · Ribosomal RNA was the only form of RNA that had been clearly identified, and it was quite possible that this was the RNA intermediary between DNA and proteins that so many scientists assumed existed. Above all, there was no good evidence that any form of RNA existed without being bound up with a protein [21] Protein synthesis within chloroplasts relies on two RNA polymerases. One is coded by the chloroplast DNA, the other is of nuclear origin. The two RNA polymerases may recognize and bind to different kinds of promoters within the chloroplast genome. The ribosomes in chloroplasts are similar to bacterial ribosomes Jul 31, · Decoding an mRNA to make a protein is a lot more complex than just matching a new nucleotide to an existing one, as DNA and RNA polymerases do. As a result the ribosome is a much larger and more
Transcription and Translation | Basic Biology
In this science project you will build your own gel electrophoresis chamber and use it to compare molecules in different colors of food coloring dye. This science project was adapted from DiSpezio, M. The Gene Hunters: Build an Electrophoresis Chamber. Part of the Scientific American Frontier's Teachers' Guide.
A forensic scientist sits in her lab with three DNA samples in front of her. One sample is the DNA left behind at the crime scene by the criminal; the other two samples are DNA from possible suspects.
How will she determine if either of the suspects' DNA matches the crime scene DNA? The scientist knows she can use an enzyme to cut each DNA sample at a particular sequence of nucleotides; this will leave behind several different pieces of DNA. The exact number of pieces and their sizes will be unique to dna makes rna makes protein essay individual.
This means that there will be an exact match in the pattern of different-sized pieces of DNA between one of the suspects dna makes rna makes protein essay the DNA left at the crime scene, but not to any other suspects' DNA.
The only problem left is, how will she "see" and "measure" the different pieces of DNA in each sample? You might have seen such a scene on the television show CSI.
The answer is gel electrophoresis! Gel electrophoresis is a technique used to separate and view macromolecules. Macromolecules are "large" molecules, such as DNA, RNA, and proteins. During gel electrophoresis, the macromolecules DNA in the forensics example above are loaded into a gel, dna makes rna makes protein essay.
Then a current is applied across the gel. The result is a separation of the macromolecules, based on mass. In order to "see" the macromolecules in the gel, scientists add either dyes, which stain the area of the gel that contains the macromolecules, or chemicals that bind the macromolecules and fluoresce when the gel is exposed to ultraviolet light. So how does gel electrophoresis work?
It is based on the principle that nucleic acids, like DNA and RNA, are negatively charged, dna makes rna makes protein essay. This means that if you put nucleic acids in an electric field, they will migrate away from the negative end of the field and toward the positive end. The nucleic acids are placed inside the gel for two main reasons.
One, the gel is a way of holding them to know where they are. Two, the migration needs to occur in a manner that allows for the separation of different-sized pieces of DNA or RNA.
The gel has many microscopic holes through which the nucleic acids wiggle as they migrate within the electric field. The smaller the nucleic acid sequence, the easier it is for it to wiggle through the holes. So, smaller pieces of DNA and RNA "run" through the gel faster than larger pieces. Returning to our forensic science example, this means that the individual pieces of DNA in each sample are sorted within the gel—the larger pieces appear at the top of the chamber and the smaller pieces appear at the bottom of the chamber.
The scientist compares the pattern of the pieces of the crime scene DNA to the pattern of the suspects' DNA and looks to see if there is an exact match. Protein gel electrophoresis works similarly, except that proteins are not always negatively charged.
In order to force the proteins to migrate toward the positive end of the electric field, the proteins are denatured, forced to unfold, in the presence of a chemical that coats the protein in negative charges.
The amount of coating is relative to the size of the protein, which means that the total negative charge is greater in larger proteins. Using this technique, proteins, like nucleic acids, can be separated based on mass.
Gel electrophoresis is a common technique in laboratories and has many uses, including the forensics example above. The most common uses are:. For example, a scientist may want to dna makes rna makes protein essay more about dna makes rna makes protein essay proteins that a bacteria releases into the environment.
To do this, the scientist collects the liquid media the bacteria grows in and runs a sample of the media in a gel to look at how many proteins are in there. Perhaps the scientist wants to know the identity of one of the proteins. Based on size, the scientist may be able to guess what some of those proteins are; to check if he's right, the scientist can take advantage of the fact that the protein is now "trapped" in the gel.
By cutting out the region of the gel containing the protein that's the size he's interested in, and using other techniques to separate the gel from the protein, he can purify the protein and use that pure sample for further experimentation. The equipment for gel electrophoresis is fairly simple. There is a chamber to hold the actual gel. The chamber has both positive and negative electrodes to which you connect a power source in order to create the electric field, dna makes rna makes protein essay.
The gel is immersed in a buffer solution, dna makes rna makes protein essay, which provides ions to carry the current and keeps the pH fairly constant.
The sample is loaded into wells in the gel. In this science project you'll build your own gel electrophoresis chamber. Once it is built, you'll be able to examine different food coloring dyes and explore some of the following questions. For a preview of what the experiment will look like, watch the video below. How many different macromolecules make up each food coloring dye? Is there only one per color? Which color runs through the gel fastest?
Do different brands of food dyes contain the same macromolecules? You might be surprised by the results! Before starting this science project you will need to familiarize yourself with the following terms:.
Once your gel electrophoresis chamber is built, you will need the following items to run your experiment:. To start this science project, you will first need to build your gel electrophoresis chamber. The plastic box will be the actual dna makes rna makes protein essay chamber, the stainless steel wire will be the electrodes, the batteries will be the power source, and you'll use the Styrofoam to make a comb for creating wells in your gel.
Once you've assembled your gel electrophoresis chamber, you are ready to start your food coloring dye separation experiment. The first step in the experiment is to make the buffer solution that you will use for both making the agar gel and running the samples. To make this, combine 2 grams g of baking soda with mL of bottled water in one of your bowls and stir well. If you don't have a kitchen scale, 2 g of baking soda is approximately ½ teaspoon.
If you don't have a kitchen scale, 1 g of agar is approximately ¼ teaspoon. Heat the agar solution in a microwave to dissolve the powder. Stop the microwave every seconds to stir the solution, dna makes rna makes protein essay. When you see that the solution is starting to bubble, remove it from the microwave.
The solution should be translucent. Make sure to watch the agar solution carefully and remove it promptly from the microwave; when it gets hot it will easily bubble over. Remove the stainless steel wire electrodes from the gel chamber. Insert the Styrofoam comb into either end of the gel chamber, leaving approximately 0. Gently pour the agar solution into the gel chamber.
Add just enough solution to the box so that the comb teeth are submerged approximately 0. If the gel is too thick, it will be difficult to observe good separation of the food coloring dyes.
Figure 5. To form the wells, there must be a few millimeters of space between the bottom of the comb's teeth and the plastic box. Wait until the gel solidifies, which may take at least 30 minutes at room temperature. Tip: When the gel is set, it should be firm to the touch and wiggle like solid jello. Pour the remaining mL of your buffer solution over the solidified gel. Add enough buffer to submerge the gel. Gently pull the comb out of the gel. Be sure not to remove the comb until you are sure that the agar gel is completely set.
The resulting wells will be used as reservoirs for your samples. Using the butter knife, carefully cut a thin slice of the gel from the top and the bottom to make room for the electrodes. Re-attach the stainless steel wire electrodes.
Using a plastic syringe or medicine dropper, fill each well in the gel with a different color of food dye. A small drop of food coloring dye is sufficient. You might find it easier to first put a drop of food coloring dye on a piece of wax paper and then use a syringe or medicine dropper to transfer the food coloring dye from the wax paper to the gel, dna makes rna makes protein essay.
Using the alligator clip leads, attach the battery pack to the wires resting on the gel chamber. The positive terminal of the battery pack should be connected to the positive electrode; this is the electrode toward which you want the food coloring dye to migrate as it separates. You should see bubbles forming around the electrodes in the buffer as the current passes through them.
If you don't see bubbles, recheck all your electrical connections, dna makes rna makes protein essay. Make sure the batteries are properly placed in series, and that the batteries are fresh and fully charged. Figure 6. Gel electrophoresis chamber running samples of food coloring dye. Notice the bubbles forming around the electrodes. Check the progress of your gel every minutes. Run the gel until you see good migration and separation of the food coloring dyes.
If you've used the electrophoresis chamber in a previous trial and feel that it is no longer working as efficiently, you might need to troubleshoot the following: Replace the batteries with fresh, fully charged ones.
Running the electrophoresis chamber can drain the batteries.
Translation (mRNA to protein) - Biomolecules - MCAT - Khan Academy
, time: 14:11Forensic Science: Building Your Own Tool for Identifying DNA | Science Project
Jul 31, · Decoding an mRNA to make a protein is a lot more complex than just matching a new nucleotide to an existing one, as DNA and RNA polymerases do. As a result the ribosome is a much larger and more Sep 15, · Though most DNA is transcribed to RNA and then translated into protein, reverse transcriptase involves the opposite, i.e., RNA converting back to DNA, which, though used by viruses, is also Aug 31, · DNA → RNA → Protein. DNA and RNA are similar molecules and are both built from smaller molecules called nucleotides. Proteins are made from a sequence of amino acids rather than nucleotides. Transcription and translation are the two processes that convert a sequence of nucleotides from DNA into a sequence of amino acids to build the desired
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