DNA is a natural polymer that stores genetic instructions
Definition
Genetic instructions
Coded information that directs the development and functioning of a living organism or virus.
- DNA stands for deoxyribonucleic acid and is a large molecule essential for life.
- DNA encodes genetic instructions, meaning it stores coded information.
- These instructions direct the development and functioning of living organisms and viruses.
- DNA is a naturally occurring polymer made from many joined monomers.
Key Idea
- DNA is a polymer whose biological role is to encode genetic instructions.
- Those instructions carry the information needed for development and functioning.
Two nucleotide chains coil into a double helix
Definition
Polymer
A substance made from very large molecules in which many atoms are linked by strong covalent bonds.
- Most DNA molecules are made of two polymer chains.
- Each chain is many monomers called nucleotides joined in a sequence.
- DNA uses four different types of nucleotide monomer.
- The two chains coil around each other to form a double helix.
- Double refers to the two chains and helix to their coiled shape.
Exam technique
- Call a nucleotide the monomer and DNA the polymer; do not call a nucleotide a polymer.
- Say DNA has many nucleotides of four different types, not just four nucleotides.
Proteins, starch and cellulose are named by their monomers
Definition
Monomer
A small molecule that can join with many other monomer molecules to form a polymer.
- Proteins are natural polymers made from amino acid monomers.
- Starch is a natural polymer made from sugar (glucose) monomers.
- Cellulose is a natural polymer made from sugar (glucose) monomers.
- To identify one of these natural polymers, name the monomer it is built from.
Self review
- What does DNA encode?
- What type of monomer forms DNA?
- What shape do the two chains in most DNA molecules form?
- What type of monomer forms proteins?
- Which natural polymers are made from sugar monomers?
