2.3 Nucleotides and nucleic acids Flashcards
What is a DNA nucleotide made of?
A DNA nucleotide is made from a nitrogenous base, a deoxyribose sugar and a phosphate group
What is a RNA nucleotide made of?
An RNA nucleotide is made from a nitrogenous base, a ribose sugar and a phosphate group.
What are the nitrogenous bases?
Adenine (A)
Cytosine (C)
Guanine (G)
Thymine (T)
Uracil (U)
Which nitrogenous bases are purines?
Adenine and Guanine
They have 2 rings
Which nitrogenous bases are pyrimidines?
Thymine, Cytosine and Uracil
They have 1 ring
How is a phosphodiester bond formed?
Condensation reaction, the hydrogen from the hydroxyl group on C3 of the sugar on one nucleotide, and the hydroxyl group from the phosphate group of the other nucleotide are removed. A dinucleotide and a molecule of water are formed.
How is a phosphodiester bond broken?
Hydrolysis reaction, to break the phosphodiester bond, a molecule of water is added to the bond, which adds a hydrogen atom to the carbon 3 of the sugar ad a hydroxyl group of the phosphate group.
What is the structure of DNA?
The two DNA strands are antiparallel, which means that the 3rd and 5th carbon on the deoxyribose sugar are facing in opposite directions. As the two DNA strands twist, a double helix shape is formed.
How do you extract and purify DNA?
DNA is found in the nucleus of a cell. To extract and purify the DNA, the membranes need to be broken mechanically and chemically, using detergent and salt. The mixture is then filtered to remove cell debris.
Who discovery DNA?
James Watson and Francis Crick discovered the double helix structure of DNA in 1953, with significant contributions from Rosalind Franklin and Maurice Wilkins.
