What is a nucleotide?
A nucleotide is the basic unit that makes up DNA. A singular nucleotide is made up of x3 components:
- A base (A, T, C or G)
- 5 Carbon sugar (deoxyribose = DNA or ribose = RNA)
- Phosphate group (forms a bond between the sugar molecules in a DNA chain = phosphodiester bond) Bases There are x4 different nitrogenous bases that comprise DNA.
- Adenosine
- Cytosine
- Thymine
- Guanine
There are two groups of nucleotides pyrimidines and purines
Pyrimidines Thymine and Cytosine are the smallest of the 4 bases. With only 1 ring in their structure. In RNA, Thymine is replaced by Uracil all other bases are the same
Purines Adenosine and Guanine are purines. Their structure contains a pyrimidine ring + a smaller 5 sided ring. Therefore making a 2 ringed structure.
HA
Related Human Biology A Level answers
All answers ▸Through which chambers and valves does the blood flow in the human heart?
Describe the role of the heart and lungs in the oxygenation of blood in humans. Why is oxygen is essential for the functioning of the human body.
Describe the structure of the human heart and how the blood is pumped by the heart.
Why is atrial repolarisation not present on an ECG yet ventricular repolarisation is?