Cells use their chromosomes like a set of blueprints to make new proteins, RNA, and one-of-a-kind molecules like histone proteins. This exciting process is called gene expression, and it involves the cell’s machinery performing these steps:
Genome is really big
The human genome is made up of 3 billion nucleotides, which are arranged in the specific order that makes you.If you wanted to read the entire human genome in a single run, it would take about 400 years at the rate of one letter per second.That’s why we don’t do it that way. Instead, scientists have developed many different ways to speed up this process and get the job done much more quickly.
One method is called shotgun sequencing. Here’s how it works: First we break up our DNA into tiny pieces with enzymes called restriction enzymes, which cut DNA at specific locations called restriction sites. By taking advantage of these sites and cutting them in several different ways, we can create thousands of smaller pieces of DNA each piece contains only a few hundred base pairs from our original sequence.
The genome is a set of instructions for making proteins
It’s made up of DNA, which is copied into RNA, translated into protein and then folded into proteins.DNA is a double helix that looks like two spiral staircases wrapped around each other.
The steps of each staircase are made up of four different chemicals called bases (abbreviated A, C, T and G). These are the letters in the language of life. Each base has one partner: A always pairs with T and C always pairs with G. These base pairs hold together the two sides of the DNA molecule and form what’s known as a nucleic acid duplex structure.
In order to make proteins from the genome, these nucleic acid duplexes must be copied into messenger RNA (mRNA) molecules but that’s not all! The mRNA must also be translated into amino acids that can be assembled into proteins.
This process involves many steps that take place in the cell nucleus as well as in cytoplasmic ribosomes subunits within cells where proteins are synthesized from amino acids according to instructions contained in mRNA molecules.
Double strand of molecules
The DNA in your cells is a double strand of molecules that form the genome. The genome is made up of genes, which are sequences of DNA that code for specific proteins.When cells need to read from their genetic code to build proteins, they use machinery called ribosomes to translate parts of the genome into amino acids, which are the building blocks for proteins.
There are two major types of ribosomes: large and small.Large ribosomes make up 80 percent of the ribosome pool in a cell but are responsible for translating RNA transcripts into protein. Small ribosomes make up 20 percent of the ribosome pool but are responsible for translating mRNA transcripts into protein.
Like a barcode, the sequence of letters in DNA encodes the instructions for life
The genome is made of long strands of DNA, which can be thought of as chains of letters (A, T, G and C). Each cell contains a copy of this genetic code, which tells that cell how to make proteins. But it’s not just a simple matter of reading the letters in order and translating them into proteins.
First, the DNA is modified by enzymes called methyltransferases.
These add a methyl group to one or more bases on each strand. The methyl groups stick out from the DNA like little hooks so that when other proteins bind to them, they can pull the molecule into tight coils. This helps control which parts of the genome are accessible at any given time and also makes it easier for enzymes called transcription factors to latch on and start reading out the code in chunks.
Transcription factors work by attaching themselves to certain areas on the DNA strand for example, near where a gene starts or stops coding for protein. They then recruit other proteins that unwind this area so that RNA polymerase can move into position over it and start reading out its instructions.
The genome is constantly being transcribed into proteins
This process is regulated so that only the right amount of each protein is made at any given time.The genome comprises the entire set of genes in a cell, which encode its blueprint for life. The complete set of human genes is called the genome. Genes are pieces of DNA that code for specific proteins.
Genes are divided into exons and introns, which are separated by noncoding regions called introns. The exons are joined together by splicing during transcription, resulting in messenger RNA (mRNA). mRNA contains the information needed to create a protein from amino acids.
Amino acids which bond together in unique ways
Proteins are made up of amino acids, which bond together in unique ways. The sequence of amino acids determines the shape of the protein, which in turn determines its function. For example, some proteins are enzymes that catalyze chemical reactions; others carry oxygen from your lungs to your tissues; and still others make up your hair, skin and nails.
The DNA in our cells contains information about all of these things. But how does that information get from DNA to a protein? This is where transcription factors come into play. They’re like molecular “translators” that read DNA instructions and then tell the cell where to start making a new protein.
Conclusion
Cells have a lot of functions so there are many different proteins that are involved in each one of them.Cells need to make many proteins so they have different genes that encode these types of proteins. A gene is a segment of DNA that some information can be converted into protein.