BTEC APPLIED SCIENCE
UNIT 11 Genetics and Genetic Engineering –
Learning Aim D
Describe and explain what a nucleotide is:
A phosphate group, a sugar, and a base are the three components of a nucleotide. (“What are
the three components of a nucleotide - Brainly.com”) They are sugars and bases that make up
DNA and RNA. An organic molecule is referred to as a base. Purines and pyrimidines are the
two types of bases. Purines are adenine and guanine, while pyrimidines are thymine, uracil,
and cytosine. (“Expand ATP class 12 biology CBSE”)
, Helmenstine, A., 2022. What Are the Three Parts of a Nucleotide?. [online] Science Notes and Projects. Available
at: <https://sciencenotes.org/what-are-the-three-parts-of-a-nucleotide/> [Accessed 3 March 2022].
Nitrogen bases:
5 nitrogen containing bases (nucleotides):
- Cytosine (DNA & RNA)
- Thymine (DNA)
- Adenine (DNA & RNA)
- Guanine (DNA & RNA)
- Uracil (RNA)
Ib.bioninja.com.au. 2022. [online] Available at: <https://ib.bioninja.com.au/_Media/nitrogenous-bases_med.jpeg>
[Accessed 3 March 2022].
Purines are one of two chemical compounds used by cells to make the DNA and RNA building
blocks. Adenine and guanine are examples of purines. Purines can also be found in foods, such
as meat. Their structures have two rings in them. Guanine and adenine are two examples of
these. The second class of nitrogen bases is pyrimidine. Cells use these to create the DNA and
RNA building blocks. Pyrimidines are single-ringed structures with a smaller size. Cytosine,
uracil, and thymine are examples of these.
Describe and explain the structure of a DNA molecule
Nucleotides, which make up DNA, are repeating units. A polynucleotide is a structure that has
more than two nucleotides joining them together. DNA is made up of strands of
polynucleotides. They are antiparallel – they are structured in such a way that they run in
opposite directions. Allowing nucleotides to be connected, covalent bonds form between the
phosphate group of one nucleotide and the third carbon atom of the pentose sugar in the next
UNIT 11 Genetics and Genetic Engineering –
Learning Aim D
Describe and explain what a nucleotide is:
A phosphate group, a sugar, and a base are the three components of a nucleotide. (“What are
the three components of a nucleotide - Brainly.com”) They are sugars and bases that make up
DNA and RNA. An organic molecule is referred to as a base. Purines and pyrimidines are the
two types of bases. Purines are adenine and guanine, while pyrimidines are thymine, uracil,
and cytosine. (“Expand ATP class 12 biology CBSE”)
, Helmenstine, A., 2022. What Are the Three Parts of a Nucleotide?. [online] Science Notes and Projects. Available
at: <https://sciencenotes.org/what-are-the-three-parts-of-a-nucleotide/> [Accessed 3 March 2022].
Nitrogen bases:
5 nitrogen containing bases (nucleotides):
- Cytosine (DNA & RNA)
- Thymine (DNA)
- Adenine (DNA & RNA)
- Guanine (DNA & RNA)
- Uracil (RNA)
Ib.bioninja.com.au. 2022. [online] Available at: <https://ib.bioninja.com.au/_Media/nitrogenous-bases_med.jpeg>
[Accessed 3 March 2022].
Purines are one of two chemical compounds used by cells to make the DNA and RNA building
blocks. Adenine and guanine are examples of purines. Purines can also be found in foods, such
as meat. Their structures have two rings in them. Guanine and adenine are two examples of
these. The second class of nitrogen bases is pyrimidine. Cells use these to create the DNA and
RNA building blocks. Pyrimidines are single-ringed structures with a smaller size. Cytosine,
uracil, and thymine are examples of these.
Describe and explain the structure of a DNA molecule
Nucleotides, which make up DNA, are repeating units. A polynucleotide is a structure that has
more than two nucleotides joining them together. DNA is made up of strands of
polynucleotides. They are antiparallel – they are structured in such a way that they run in
opposite directions. Allowing nucleotides to be connected, covalent bonds form between the
phosphate group of one nucleotide and the third carbon atom of the pentose sugar in the next
