DNA Ligase
An enzyme that joins DNA fragments by forming phosphodiester bonds, essential for creating recombinant DNA.
What is DNA Ligase?
A type of covalent bond that links two nucleotides together in a DNA or RNA strand, connecting the 5' carbon of one sugar to the 3' carbon of another sugar via a phosphate group.
Key points
- To understand the function of DNA ligase in joining DNA fragments.
- To identify the chemical bond formed by DNA ligase.
- To recognize the role of DNA ligase in recombinant DNA technology.
- To recall the energy source required for DNA ligase activity.
Common exam trap
Confusing DNA ligase with restriction enzymes (which cut DNA).
Definitions
- Term
Phosphodiester bond
- Meaning
A type of covalent bond that links two nucleotides together in a DNA or RNA strand, connecting the 5' carbon of one sugar to the 3' carbon of another sugar via a phosphate group.
- Term
Recombinant DNA
- Meaning
DNA molecules formed by laboratory methods of genetic recombination to bring together genetic material from multiple sources, creating sequences that would not otherwise be found in the natural genome.
Learning objectives
To understand the function of DNA ligase in joining DNA fragments.
To identify the chemical bond formed by DNA ligase.
To recognize the role of DNA ligase in recombinant DNA technology.
To recall the energy source required for DNA ligase activity.
Prerequisites
Basic understanding of DNA structure (nucleotides, phosphodiester bonds).
Knowledge of DNA replication and repair mechanisms.
Familiarity with restriction enzymes and their action.
Common mistakes
Confusing DNA ligase with restriction enzymes (which cut DNA).
Forgetting the energy requirement for its function.
Not understanding its role in sealing the 'nicks' in the DNA backbone.
Keywords
DNA ligase
Enzyme
Phosphodiester bond
Recombinant DNA technology
Molecular glue
ATP
NAD+
Gene cloning
DNA repair
Practice preview
Which enzyme is primarily responsible for joining DNA fragments during the synthesis of recombinant DNA?…
easy
In recombinant DNA technology, what is the role of DNA ligase?…
easy
The formation of phosphodiester bonds between DNA fragments is catalyzed by:…
easy