Nucleotides and Lipids Flashcards
What are the two types of Nucleic Acid in Living Cells?
- Deoxyribonucleic Acid(DNA)
- Ribonucleic Acid(RNA)
What are Nucleic Acids made from?
Nucleic acids are polymeric molecules made up of monomeric units called nucleotides
When nucleotides are linked together, what is formed?
Nucleotides link together to form polynucleotide chains.
In RNA these can be thousands of units in length
In DNA these can be millions of units in length
What are the components of a DNA nucleotide?
Phosphate
Base
Sugar
What is the sugar component of a nucleotide?
The sugar component of the nucleotide is a pentose
Where are the nitrogenous bases attached to one the sugar?
The nitrogenous base is attached to the 1’-carbon of the sugar
What are the double ring purines?
Adenine and Guanine
What are the single ring pyrimidines?
Cytosine, Thymine and Uracil
What nitrogenous base is different between DNA and RNA?
Both DNA and RNA contain Adenine, Guanine and Uracil.
DNA also contains Thymine
RNA contains Uracil instead of Thymine
What bond joins the base to the sugar?
Beta-N-glycosidic bond
Attached to nitrogen number 1 of the pyrimidine base
Attached to nitrogen number 9 of the purine base
What is a molecule compromising the sugar joined to a base called?
A molecule compromising the sugar joined to a base is called a nucleoside
What converts a nucleoside into a nucleotide?
The attachment of a phosphate group to the 5’-carbon of the sugar
What bonds are Nucleotides joined by?
Nucleotides are joined by a phosphodiester bond
How are the nucleotide monomers linked together?
The nucleotide monomers are linked together by joining the alpha-phosphate group, attached to the 5’-carbon of one nucleotide, to the 3’ carbon of the next nucleotide in the chain.
What phosphates are ‘cleaved off’ during polymerization of nucleoside triphospate?
Beta-phosphates and y-phosphates
What does the phosphodiester bond mean?
‘phospho’ indicates a phosphorus atom
‘diester’ refers to the two ester (C-O-P) bonds in each linkage
Which end has not participated in a phosphodiester bond in a DNA trinucleotide?
5’-carbon has not participated in a phosphodiester bond and the beta and y-phosphates are still in place.
This is known as the 5’ end/terminus
Which end is the unreacted group in a phosphodiester bond in a DNA trinucleotide?
The unreacted group is the 3’-hydroxyl group.
This is known as the 3’ end or 3’-OH Terminus
How are the two polynucleotides arranged in a double helix structure?
The two polynucleotides are arranged anti-parallel to each other (they run in different directions), so that their sugar-phosphate ‘backbones’ are on the outside of the helix structure
What is the wide and deep groove in a double helix structure known as?
The Major Groove
What is the narrow and less deep groove in a double helix structure known as?
The Minor Groove
How many chemical interactions is the helix structure stabilized by?
The helix is stabilized by 2 types of chemical interactions;
1. Hydrogen bonds- which form between the bases that are adjacent to each other
2. Base Stacking- attractive forces between adjacent base pairs which and adds stability to the double helix once the strands have been brought together by hydrogen bonding
What bases can be paired together?
Adenine and Thymine
Guanine and Cytosine
What is base stacking due to?
Base stacking is due to the attraction between the aromatic rings of the nucleotide bases
