![]() They are like the front and back cover of a book they serve to denote the beginning and the end of the information contained within. Perhaps one of the coolest is by turning particular genes off through a process called DNA methylation.Įach gene is outlined by two separate DNA sequences in the genome-a promoter sequence (the start of the gene), and a terminator sequence (the end of the gene). There are several ways that the cell manages to up-regulate or down-regulate its mRNA levels. If you need more proteins, just place an order for more! DNA Methylation Similarly, if you need to boost production of a certain protein, it’s also fairly easy to regulate at this point as well. Your time and money will have been wasted. Otherwise, you’d have to wait for it to get to you and then decide you don’t need it anymore. It’s a bit like cancelling an unwanted order before it’s shipped to you. That way, your cell isn’t wasting time with stuff it’s already built further down the road. Transcription is the start of everything, so it’s easiest to regulate which genes are used or not at this point. Transcription: The First Regulation Point At the end, the ribosome falls off and the chain is finished-except now the amino acid chain is called a protein. The ribosome then slides down the mRNA template, reads the code, and assembles a chain of amino acids based on whatever the code says. Our little mRNA template then floats peacefully out of the nucleus and into the cytoplasm (the rest of the liquidy goop that makes up the inside of the cell), where a ribosome attaches to it. The RNA polymerase slides down the DNA and spits out and exact mRNA copy of the gene. This mRNA template is then translated into an actual protein.įirst, DNA is transcribed into an mRNA template when RNA polymerase (the gene copying machine) attaches to a gene on the DNA strand. In transcription, the goal is to produce an mRNA (messenger RNA) copy of an entire gene from its DNA template. There are two major cellular processes that produce proteins: transcription and translation. Genes can be regulated at each one of these steps, so it’ll be helpful to go over them what they are. There are a lot of steps that happen in the process that starts with a cell’s DNA and ends with a protein. The Big Picture: What’s happening in the cell, and where can we control it? In fact, we haven’t even discovered them all yet! In this article, we’ll go over some of the most common ways that cells can regulate and express genes. This process is called gene regulation and expression, and there are many ways that cells can do it. Cells can also adjust the “volume” of each gene and control how many proteins are produced. Instead, the toenail-making cell creates keratin (a protein found in your nails), while the heart muscle-making cell disables this gene.Įach cell in your body has ways to turn genes on and off, just like you going through your house and flipping the on/off switches. It’s all in how each cell expresses them! The toenail-making cell, for example, does have the gene to make myoglobin (a protein found in muscle cell), but it has disabled the gene for that particular protein (could you imagine if it did? Your toenails would turn red and could absorb oxygen!). ![]() So what distinguishes the toenail-making cell from the bone-making cell and the heart muscle-making cell if they all have the same genes? The cells that make your toenail, for example, still have the genes that a heart muscle cell or a bone cell uses to make heart and bone-specific proteins. Each one of your 37.2 trillion cells has a complete copy of all of the genes within your DNA, but they’re not all turned on at the same time. Your home is a precisely-tuned system when you think about it! To get things back to normal, you’d need to go through and turn off the things you didn’t need on or adjust the volume and settings so you’re getting the proper amount of sound, heating, cooling, etc. The radio and the TV would be blaring, the fridge would turn into a freezer, and your home heating system would melt you into a puddle of sweat. To get an idea of how gene regulation and expression work in your cells, imagine someone went through your house and turned on all your electrical components at full-blast. ![]()
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