Introduction to DNA & RNA
Biology: Cambridge International A Level, topic 6.1.1
DNA and RNA
The two main types of nucleic acids are DNA and RNA.
What is DNA?
- Deoxyribonucleic acid (DNA) is an important information-carrying molecule.
- DNA is the genetic material in all living organisms, ranging all the way from single-celled bacteria to multicellular mammals.
- The DNA code tells the cell what to do and what proteins to make.
- The cell's entire genetic content is called its genome and the study of genomes is genomics.
Eukaryotic vs prokaryotic DNA
- In eukaryotes, DNA is found mainly in the nucleus but there is also some in chloroplasts and mitochondria.
- In prokaryotes, the DNA is not enclosed in a membranous envelope.
What is RNA?
- Ribonucleic acid (RNA) is similar to DNA.
- RNA is mostly involved in synthesizing (making) proteins.
- Ribosomes are formed from RNA and proteins and are the protein builders of the cell.
The role of mRNA
- DNA never leaves the nucleus so uses messenger RNA (mRNA) to transfer genetic information to the rest of the cell.
- mRNA moves out of the nucleus to transfer information to the ribosomes in order to make proteins.
Test yourself on Introduction to DNA & RNA
What is the cell's entire genetic content called?
Where is DNA found in prokaryotes?
Which of the following is true of DNA?