DNA structure Flashcards
What is DNA?
Deoxyribonucleic acid ( DNA ) codes for the sequence of amino acids in the primary structure of a protein, which in turn determines the final 3D shape and function a protein. The polymer is a double helix.
Why is DNA essential?
essential therefore the cells that may contain a copy of this genetic code can pass it onto new cells without being damaged.
What is DNA nucleotide?
The monomer that makes up DNA is called a nucleotide. It comprises deoxyribose (pentose sugar ), a nitrogenous base, and one phosphate group. The nitrogenous bases can include adenine, guanine, cytosine, and thymine.
What is a polynucleotide?
The polymer of these nucleotides is called a polynucleotide.
How are polynucleotides created?
They are created via condensation reactions between the deoxyribose sugar and a phosphate group, creating a phosphodiester bond.
What are phosphodiester bonds?
They are strong covalent bonds, therefore help ensure that the genetic code isn’t broken down.
What else do polynucleotides consist of?
It has a sugar-phosphate backbone. Describes the strong covalent bonds between the sugar and the phosphate group that hold the polymer together.
How do hydrogen bonds relate to DNA polymer?
The DNA polymer occurs in pairs, and these pairs are joined together by hydrogen bonds between the bases. This is how the double helix is created, as two chains twist. Hydrogen bonds can form between complementary base pairs.
Adenine and thymine can form 2 hydrogen bonds, and cytosine and guanine can form 3 hydrogen bonds. This complementary base pairing is important to help maintain the order of the genetic code when DNA replicates.
How does the structure relate to the function?
- Stable structure due to the sugar-phosphate backbone ( covalent bonds ) and the double helix.
- Double-stranded so replication can occur using one strand as a template.
- Weak hydrogen bonds for easy unzipping of the two strands in a double helix during replication.
- Large molecule to carry lots of information.
- Complementary base pairing allows identical copies to be made.
