Important Topic for SSC Exams : DNA/RNA

Important Topic for SSC Exams (Biology Topic : DNA, RNA)

What is DNA ?

Full form of DNA: Deoxyribonucleic acid

The structure of DNA was established by James Watson and Francis Crick.


DNA is the hereditary material in humans and almost all other organisms. Nearly every cell in a person’s body has the same DNA. Most DNA is located in the cell nucleus (where it is called nuclear DNA), but a small amount of DNA can also be found in the mitochondria (where it is called mitochondrial DNA or mtDNA).

The information in DNA is stored as a code made up of four chemical bases:
1. adenine (A)
2. guanine (G)
3. cytosine (C)
4. thymine (T).

Human DNA mainly consists of about 3 billion bases, and more than 99 % of those bases are the same in all the people.

DNA bases pair up with each other:

A (adenine) with T (thymine)
C (cytosine) with G (guanine)

to form units called base pairs. Each base is also attached to a sugar molecule and a phosphate molecule. Together, a base, sugar, and phosphate are called a nucleotide.

















Nucleotides are arranged in two long strands that form a spiral called a double helix.
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Tricks to remember base pair: AT CG (American Tourister is now in Chattis Garh).
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What is RNA ?

Full form: Ribonucleic acid

DNA remains in the nucleus, but in order for it to get its instructions translated into proteins, it must send its message to the ribosomes, where proteins are made. The chemical used to carry this message is Messenger RNA.

RNA is similar to DNA except:

1. has on strand instead of two strands.
2. has uracil instead of thymine
3. has ribose instead of deoxyribose


mRNA has the job of taking the message from the DNA to the nucleus to the ribosomes.

- RNA is made from DNA.
- Proteins are made from the message on the RNA.






Expected question:


  • DNA Full Form.
  • Question from Base pair like. Adenine pair up with ______.
  • If the DNA found in mitochondria it is called ___________.
  • DNA located in the nucleus is called ________.
  • If a base, sugar, and phosphate together, are called a __________.
  • RNA full form.
  • RNA is made from ________.

Important for SSC MTS, SSC CGL, SSC CPO, SSC 10+2 Level Exams.