More Biological Molecules - Inorganic Ions Flashcards
What is a cation?
An ion with a positive charge.
What is an anion?
An ion with a negative charge.
What is an inorganic ion?
An ion that doesn’t contain carbon
(although there are a few exceptions).
There are inorganic ions, in solution, in the ____________ __ _____ and in the _____ ______ __ __________.
There are inorganic ions, in solution, in the cytoplasm of cells and in the bodily fluids of organisms.
NOTE:
An ion’s role determines whether it is found in high or low concentrations.
What is the role of IRON IONS?
IRON IONS are an important part of HAEMOGLOBIN.
Haemoglobin is a large protein that carries oxygen around the body, in the red blood cells.
Haemoglobin is made up of four different polypeptide chains, each with an IRON ION (Fe2+) in the centre.
It’s the Fe2+ that actually binds to the oxygen in haemoglobin – so it’s a pretty key component.
When oxygen IS bound, the Fe2+ ion temporarily becomes an Fe3+ ion, until oxygen is released.
What is the role of HYDROGEN IONS (H+)?
HYDROGEN IONS (H+) determine pH.
pH is calculated based on the CONCENTRATION of HYDROGEN IONS (H+) in the environment.
The MORE H+ present
the LOWER the pH
the more ACIDIC the environment.
Enzyme-controlled reactions are all affected by pH.
What is the role of SODIUM IONS (Na+)?
SODIUM IONS (Na+) help TRANSPORT GLUCOSE and AMINO ACIDS across MEMBRANES.
Glucose and amino acids need a bit of help crossing cell membranes.
A molecule of glucose or an amino acid can be transported into a cell (across the cell-surface membrane) alongside sodium ions (Na+).
This is known as co-transport.
What is the role of PHOSPHATE IONS?
PHOSPHATE IONS are an ESSENTIAL COMPONENT of ATP and DNA.
When a phosphate ion (PO4^3-) is attached to another molecule, it’s known as a phosphate group.
DNA, RNA and ATP all contain phosphate groups.
It’s the bonds between phosphate groups that store energy in ATP.
The phosphate groups in DNA and RNA allow NUCLEOTIDES to join up to form the POLYNUCLEOTIDES.
