Biological Molecules - Monomers and Polymers Flashcards
What is a monomer?
One of many small molecules that combine together using covalent bonds to form a polymer.
What is a polymer?
A large molecule made up of many repeating smaller molecules (monomers).
What is polymerisation?
The process of making a polymer.
What is covalent bonding?
Atoms share a pair of electrons in their outer shells. As a result, the outer shell of both atoms is filled and a more stable compound, called a molecule, is formed.
What is ionic bonding?
Ions with opposite charges attract one another. This electrostatic attraction is known as an ionic bond. They are weaker than covalent bonds.
What is hydrogen bonding?
The electrons within a molecule are not evenly distributed but tend to spend more time at one position. This region is more negatively charged than the rest of the molecule. A molecule with an uneven distribution of charge is said to be polarised, or a polar molecule. The negative region of one polarised molecule and the positively charged region of another attract each other. Although each bond is individually weak, they can collectively form important forces that alter the physical properties of molecules. This is especially true for water.
What are condensation reactions?
In the formation of polymers by polymerisation in organisms, each time a new sub-unit is attached, a molecule of water is formed. Reactions that produce water in this way are termed condensation reactions.
Therefore the formation of a polypeptide from amino acids and that of the polysaccharide starch from the monosaccharide glucose are both condensation reactions.
What are hydrolysis reactions?
Polymers can be broken down through the addition of water. Water molecules are used when breaking the bonds that link the sub-units of a polymer, thereby splitting the molecule into its constituent parts. This type of reaction is called hydrolysis.
Thus polypeptides can be hydrolysed into amino acids, and starch can be hydrolysed into glucose.
What is metabolism?
All the chemical processes that take place in living organisms are collectively called metabolism.
What is the mole?
The mole is the SI unit for measuring the amount of a substance and is abbreviated to mol.
How many particles does one mole contain?
One mole contains the same number of particles as there are in 12g of carbon-12 atoms. 12g of carbon-12 contains 6.022 x 10^23 carbon atoms.
What is the Avogadro constant?
6.022 x 10^23
What is a molar solution?
A molar solution is a solution that contains one mole of solute in each litre of solution. A mole is the molecular mass expressed as grams.
What are isotopes?
While the number of protons in an element always remains the same, the number of neutrons can vary. These are called isotopes. Isotopes of any one element have the same chemical properties but differ in mass. Each type is therefore recognised by its different mass number. Isotopes, especially radioactive ones, are very useful in biology for tracing the route of certain elements in biological processes and for dating fossils.
What is an ion?
If an atom loses or receives an electron, it becomes an ion. The loss of an electron leads to the formation of a positive ion (cation) and the gain of an electron leads to the formation of a negative ion (anion).
