DNA Flashcards
What are the 3 components of a DNA structure?
A phosphate, a deoxyribose sugar and a base.
What is the difference between a Nucleoside and a Nucleotide?
A nucleoside contains a deoxyribose sugar and a base, whereas a nucleotide contains both of these plus a phosphate.
Name the bases and the pairs they form.
Adenine and Thymine & Cytosine and Guanine.
Which bases are purines?
Adenine and Guanine.
Which bases are pyrimidines?
Thymine and Cytosine.
When base pairs join, what type of bonds are formed?
Hydrogen bonds. 3 Hydrogen bonds between G & C and 2 Hydrogen bonds between A & T.
How are nucleosides formed?
Nucleosides are formed following a condensation reaction between a sugar and a purine or pyrimidine base, with the removal of water, forming an N-glycosidic bond (strong covalent bond).
How are nucleotides formed?
Nucleotides are formed following a further condensation reaction between the nucleoside and phosphoric acid. The bond formed is a phosphodiester bond, which is a strong covalent bond and stems from the elimination of another water molecule.
What is the full name for Deoxyribose?
Deoxyribonucleotides.
How is a phosphodiester bond formed?
A phosphodiester bond is formed when nucleotides are joined by covalent phosphoester bonds that are formed between the sugar of one nucleotide and the phosphate group of the next nucleotide.
In which way do opposite DNA strands run?
Anti parallel to each other, e.g. one strand is 5’ to 3’ direction and the other is 3’ to 5’ direction.
Where is DNA found within Prokaryotic cells?
Free within the cytoplasm.
Where is DNA found within Eukaryotic cells?
DNA exists in the form of chromosomes within a membrane-bound nucleus.
