DNA (deoxyribonucleic acid)

Definition

DNA (deoxyribonucleic acid) is the molecule that carries genetic instructions used in the growth, development, functioning, and reproduction of all known living organisms. It consists of two strands that coil around each other to form a double helix.

5 Must Know Facts For Your Next Test

1. DNA is composed of four nucleotide bases: adenine (A), thymine (T), cytosine (C), and guanine (G).
2. The sequence of these bases encodes genetic information.
3. Astrobiologists study DNA to understand the potential for life elsewhere in the universe.
4. DNA can be damaged by radiation, which is more prevalent in space environments.
5. The discovery of extremophiles on Earth, organisms with unique DNA allowing them to survive extreme conditions, informs the search for extraterrestrial life.

Review Questions

• What are the four nucleotide bases that make up DNA?
• Why is DNA important for astrobiology?
• How do extremophiles contribute to our understanding of potential extraterrestrial life?

Related terms

RNA:

Ribonucleic acid involved in protein synthesis and sometimes in the transmission of genetic information.

Extremophiles:

Organisms that thrive in extreme environments such as high radiation or temperature.

Genetic Code: The set of rules by which information encoded within DNA or RNA sequences is translated into proteins by living cells.