Summary Unit 6 - Nucleic acids and protein synthesis (9700) CIE

TOPIC 6: NUCLEIC ACIDS AND
PROTEIN SYNTHESIS
STRUCTURE OF NUCLEIC ACIDS AND REPLICATION OF DNA

Nucleotide Structure:
- Nucleic acids like DNA (deoxyribonucleic acid) and RNA (ribonucleic acid) are
macromolecules.
- They are polymers, meaning made up of many similar, smaller molecules
joined into a long chain.
- Nucleotides are the subunits that make up DNA and RNA.
- DNA and RNA are known as polynucleotides.

Nucleotides:
- Nucleotides are made up of three components:
- A nitrogen containing base (nitrogenous base)
- A pentose sugar (containing 5 carbon atoms)
- A phosphate group.

, ATP:
- Adenosine triphosphate (ATP) is the energy carrying molecule that provides
the energy to drive many processes inside living cells.
- is a phosphorylated nucleotide.
- Can combine with one, two and three phosphate groups:
- One phosphate = adenosine monophosphate (AMP)
- Two phosphate = adenosine diphosphate (ADP)
- Three phosphate groups = adenosine triphosphate (ATP)




Purines & Pyrimidines:
- The nitrogenous base molecules found in DNA (A,T,C,G) and RNA (A,U,C,G)
occur in purines and pyrimidines.
- Bases adenine and guanine are purines - they have double ring structure
- Base cytosine, thymine and uracil are pyrimidines - they have a single ring
structure.

DNA Structure:
- The nucleic acid DNA is a polynucleotide because it is made up of nucleotides
bonded together in a long chain.