So, since I figured there would probably be a million posts about genes and DNA in our blog, I've decided to give any poor souls out there who might have trouble understanding, a DNA crash course! :D
What is DNA?
Well, its the molecule that ensures that elephants can't give birth to tigers and roses never give birth to cacti. DNA is the abbreviation of Deoxyribonucleic Acid and it contains the biological instructions
or simply, the recipe of the species of organism it's in. As it is passed on from adult to offspring, the recipe is passed on like a family secret and the offspring are born as the same species as the parent.
Where do I find DNA?It's found in the cell nucleus. Due to the nucleus being extremely small and having to hold more than just one molecule of DNA in it, the DNA has to be tightly packed. Each of these packages are called chromosomes.
DNA unwinds during DNA replication for it to be copied and at some other times in the cell cycle for instructions to issued out for making proteins and other biological processes. However, it's in its compact chromosome during cell division for enabling transfer to new cells.
In humans and other complex organisms, DNA is also found in small amounts in cell structures called mitochondria, which generate energy for cells to function properly. DNA found in the nucleus is called nuclear DNA and the complete set of DNA of an organism is called genome. In sexual reproduction, organisms inherit half of their nuclear DNA from the male parent and the other half from the female. However, organisms inherit all of their mitochondrial DNA from the female as only egg cells keep their mitochondria during fertilization while sperm don't.
What is DNA made up of?
It is made up of building blocks called nucleotides, linked into chains.
Nucleotides are made up of 3 parts:
1. A phosphate group
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| strand of DNA |
3. One of 4 types of nitrogen bases
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| Nucleotides. Note: The sugar-phosphate group reverses on the opposite side. |
Nitrogen Bases:
1. Adenine (A)
2. Thymine (T)
3. Guanine (G)
4. Cytosine (C)
The sequence of these bases determine the biological instructions contained in a strand of DNA. For instance, ATCGTA might instruct green eyes while CGTAAT might instruct for grey ones.
Each DNA sequence that together make up an instruction is known as a gene. The size of a gene might differ ranging from 1000 nitrogen bases to even 1 million, in humans. The complete genome approximately has 3 billion bases(!!!), divided into about 20 000 genes and 23 chromosome pairs.
What is the function of DNA?
It contains the instructions needed for an organism to develop, survive and reproduce. DNA sequences are converted into messages that are used to produce proteins- complex molecules that carry out most of our body's functions.
How are DNA sequences used to make proteins?
There are 2 steps for DNA's instruction to be used to make proteins.
Step1: Enzymes read the information in a DNA molecule and transcribe it into an intermediate molecule called messenger ribonucleic acid (mRNA).
Step2: The information in the mRNA molecule is translated into the "language" of amino acids(building blocks of proteins), which tells the cell's protein-making machinery (ribosomes) the order in which to link the amino acids. This daunting task is called translation and the full (tedious and advanced) process is explained right over here. The most astonishing part is that this huge process that we can't even fully comprehend is done by our cells, which seem to know exactly what to do!
I guess that's it for today. Hope you know at least a teensy bit more now than before about DNA and its ultimate awesomeness! Check out the library for those who want to know more!
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| The Genius molecule :D |
Goodnight guys!
Love,
us
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