There is some debate regarding the true significance of the introduction of wolves into Yellowstone National Park, but there is definitely a significance. I hope that as you watch this, you can appreciate how the effect of one species on all the species around it, which is what Ecology is all about.
In all fairness, here are some of the counter arguments:
Conservationists Crying Wolf? New Study Shows Yellowstone's Ecosystem Dynamics More Complex than Previously Understood
Meyer: About those park wolves in Yellowstone ...
Unit 7: Ecology
This video is a "sequel" of a previous video that featured transcription of DNA into RNA, specifically mRNA. In this video a ribosome translates the mRNA base sequence into a sequence of amino acids to make a protein. Again, there is more detail in this video than you are expected to understand, but this video is pretty true to what happens. It starts with the mRNA leaving the nucleus. From there, the ribosome (which is actually made of two subunits), combine and attach to the mRNA (yellow strand) at what would be the start codon. From there is reads the mRNA in groups of 3 (codons). At each codon a tRNA (green) brings into the ribosome an amino acid (red). The tRNA connects its amino acid to the growing chain of amino acids and departs the ribosome. The chain of amino acids grow and can be seen extending from the ribosome as a red string. Inside the ribsome you can briefly see that tRNA attaching to the mRNA's codon with its anticodon. This is where the amino acid is connected to the amino acid chain. Eventually the ribosome will reach a stop codon. There the amino acid chain is released. The amino acid chain clumps together to create the protein. Remember, proteins are important because proteins are used in every feature and function in life. Some proteins are used in an organism's structure (for us in our skin, our muscle, hair, etc.), some enzymes are used as channels through the cell membrane performing either facilitated diffusion or active transport, some enzymes are used as enzymes, controlling the reactions that occur in our cells, while other proteins have other purposes. All in all, everything in life involves proteins. These proteins are made in translation of mRNA to an amino acid chain.
This video shows RNA transcription in much more detail. Some of the things you should notice is that the entire sequence of DNA is not transcribed, only one small part. That small part is one gene. The blue-ish molecule that races along the DNA is RNA polymerase. As it races along the DNA you can see it briefly separating the 2 DNA stands and then leaves behind a single stranded RNA molecule; you can even see the RNA nucleotides being drawn into the process. At the end of the gene (at the end of transcription) the RNA is released to eventually make its way out of the nucleus.