It's kind of ironic. Mendel during his lifetime never used the term, "gene". From his writings and data, Mendel was more familiar with discrete "factors" that were passed from parents to children. The term, "gene", is something that was recently used. Even more surprising, Mendel's work was lost for 30 years!!! His work was rejected by scientists of his day, only to rediscovered in the year 1900.
It seems that bad things tend to happen to important good people, and the men and women of science are no exception. In this section of Genetics R Us, we are going to look at genetics from the current modern viewpoint. Like Mendel, we have discovered much too. So let's started!!!!
Modern genetics is a hot topic that is taught today, however it differs from what Mendel originally thought.
One of the beautiful things about science is that it changes. Many people think this is a bad thing. "Oh NO, now science is saying something else. Scientists can't make up their minds. They say one thing and then another." I am sure you've probably heard this line before. What many people don't understand is that because science changes, we can build on the work of others. This means we can add to our existing knowledge with every new discovery. This has happened in the world of genetics. Let's take a look!!!!
Gregor Mendel was an important man. He provided a platform in genetics that still holds true today. But there were many things he didn't know, namely cells and DNA. If you remember, living things are composed of cells. Inside your cells, within the nucleus, is an acid called DNA
Modern genetics begins with looking inside of your cells.
If you remember, DNA contains "instructions" that are used by your cells to construct a living thing. It turns out that those "instructions" are packed into different pieces of DNA. That particular piece of DNA is what is refered to as a gene Genes are all in the news, so let's meet one!.
Simply put, a gene is a piece of DNA that contains instructions on how to make a protein. Basically, a cell "reads" a particular gene so it can know how to make a protein. In addition, a cell gets instructions on what to do with a protein once a protein is made. Every gene is composed of 3 parts.
3. RNA-coding sequence
Your genes are made of three simple parts.
A promoter is a repeating sequence of bases that is used by a cell to begin reading. To a cell, a gene looks like a non-ending chain of bases. A cell would get lost without knowing where to begin. The promoter solves that problem. The promoter generally is a repeating sequence of adenine and thymine bases, which is sometimes called a "TATA box"
The terminator is the portion of the gene that tells the cell where and when to stop reading the gene. Without a terminator, a cell would continue reading.
The RNA-coding sequence is the DNA between the promoter and terminator.
It is the most important part of a gene. The RNA-coding sequence is the DNA that has the actual instruction for making a protein. When a cell is "reading" a gene, it can do three things with the gene. It could simply make a copy of the gene by copying the DNA. This is called replication. A cell could just make a piece of RNA from the RNA-coding sequence. This is called transcription. Or a cell could after making the RNA, finish "reading" the RNA to create a protein. This is called translation.
When a cell is "reading" a gene, it will go thru this equation shown toward your left.
Central Dogma Of Life
The Central Dogma of Life is nothing new to you. Remember that we learned about it earlier. The only difference is that now you know about this equation in light of the gene. In later sections of Genetics R Us, we are going to look at the three processes, (Replication, Transcription, and Translation), that make up the Central Dogma of Life in greater detail. However at this point, the gene is what is more important. Indeed, the modern concept of the gene is different than what Mendel believed. However Mendel lived in a period that was very different than ours. DNA had not been discovered so it's very understandable what Mendel thought.
In the next section, we are going to unlock more secrets of the gene. What we know about genetics today is amazing. We know about the genetics of people, plants, and even frogs!!!! Let's check it out.
The genetics of frogs is even known.
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Also, check out Howstuffworks! This guy named Marshall Brain has created a business that explains how things works. The material is presented in a cool, and easy manner that makes it one of the most popular sites around.