Can you correctly label various parts of a DNA molecule?
The Correct Answer and Explanation is :
A DNA molecule is made up of several important components:
- Phosphate Group: This is one of the key building blocks of the DNA backbone. It consists of a phosphorus atom bonded to four oxygen atoms. Phosphate groups are connected to sugar molecules, linking the nucleotides together in a chain.
- Deoxyribose Sugar: DNA contains the sugar deoxyribose, a five-carbon sugar. The carbon atoms in the sugar are labeled from 1′ to 5′. The 3′ carbon links to the phosphate group of the adjacent nucleotide, and the 5′ carbon bonds with the phosphate group of the preceding nucleotide.
- Nitrogenous Bases: The four nitrogenous bases in DNA are:
- Adenine (A): Pairs with Thymine (T) through two hydrogen bonds.
- Thymine (T): Pairs with Adenine (A).
- Cytosine (C): Pairs with Guanine (G) through three hydrogen bonds.
- Guanine (G): Pairs with Cytosine (C). These bases form the rungs of the “ladder” structure of DNA, with hydrogen bonds holding the complementary pairs together.
- Hydrogen Bonds: These bonds hold the nitrogenous bases of the two complementary strands of DNA together. Adenine and Thymine are connected by two hydrogen bonds, while Cytosine and Guanine are connected by three hydrogen bonds.
- Double Helix: DNA has a double-stranded helical structure. The two strands run in opposite directions, one running 5′ to 3′ and the other 3′ to 5′. This antiparallel arrangement is crucial for replication and other processes.
- Complementary Strands: The strands of DNA are complementary, meaning the bases on one strand dictate the bases on the other. This allows for accurate copying of genetic information during cell division.
In your image, look for the sugar-phosphate backbone, the nitrogenous base pairs in the center, and the helical twist of the molecule. Let me know if you would like me to help with a more specific breakdown or if you can describe the image!