GCSE Chemistry revision

DNA (deoxyribonucleic acid) and other naturally occurring polymers

Synthetic and naturally occurring polymers (chemistry only)

AQA 4.7.3.4 Foundation & Higher

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Naturally occurring polymers are long chains of smaller molecules called monomers that exist in nature rather than being man-made.
The three key naturally occurring polymers studied in GCSE Chemistry are polypeptides, DNA, and carbohydrates.

The monomers of DNA are called nucleotides, each of which contains one of four different bases represented by the letters A, T, G, and C.
The non-base part of each nucleotide remains the same, so the four nucleotides differ only in which base they carry.
By combining nucleotides in different sequences, cells can create different codes known as genes.
DNA consists of two polymer strands linked together, which naturally coil to form a double helix, protecting the genetic code from damage.

2. DNA: Structure & Nucleotide Monomers AQA

The monomers of DNA are called nucleotides, each of which contains one of four different bases represented by the letters A, T, G, and C.
The non-base part of each nucleotide remains the same, so the four nucleotides differ only in which base they carry.
By combining nucleotides in different sequences, cells can create different codes known as genes.
DNA consists of two polymer strands linked together, which naturally coil to form a double helix, protecting the genetic code from damage.

Carbohydrates are a group of naturally occurring polymers and monomers that provide energy and are composed of only carbon, hydrogen, and oxygen.
The monomers of carbohydrates are called monosaccharides (simple sugars), and include molecules such as glucose and fructose.
The polymers of carbohydrates are called polysaccharides, and include starch, cellulose, and glycogen.
Polysaccharides are formed by joining many monosaccharide monomers together — for example, many glucose molecules combine to form starch.

3. Carbohydrates: Monomers & Polymers AQA

Carbohydrates are a group of naturally occurring polymers and monomers that provide energy and are composed of only carbon, hydrogen, and oxygen.
The monomers of carbohydrates are called monosaccharides (simple sugars), and include molecules such as glucose and fructose.
The polymers of carbohydrates are called polysaccharides, and include starch, cellulose, and glycogen.
Polysaccharides are formed by joining many monosaccharide monomers together — for example, many glucose molecules combine to form starch.

Polypeptides, DNA, and carbohydrates are all examples of condensation polymers, where monomers join together and small molecules (such as water) are released.
Each polymer has a different monomer: amino acids for polypeptides, nucleotides for DNA, and monosaccharides for carbohydrates.
The specific sequence or combination of monomers in each polymer determines its unique structure and biological function.

4. Comparing the Three Naturally Occurring Polymers AQA

Polypeptides, DNA, and carbohydrates are all examples of condensation polymers, where monomers join together and small molecules (such as water) are released.
Each polymer has a different monomer: amino acids for polypeptides, nucleotides for DNA, and monosaccharides for carbohydrates.
The specific sequence or combination of monomers in each polymer determines its unique structure and biological function.