Metals in Biology Flashcards
1) Define the term ‘bacteria leaching’
- Making elements accessible from the geosphere to the biosphere
2) State 4 elements present in mg/g level and 4 elements present in microgram/g level.
Mg/g: K > Ca >Na > Mg
Microgram/g: Zn > Fe > Cu > Sr > Se
3) State 5/6 important uses of metals in biology
- Electrochemical potentials (Na and K for nerve conductions)
- Motility (Ca for muscle contraction)
- ETC and redox reactions (Mn, Cu, Fe)
- Protein structure
- Enzymatic catalysts
- Regulatory functions (signalling: Ca is a secondary messenger, Zn)
4) State 3 examples of reactions of gases involving enzymes containing metal ions
- N2 -> NH3 : nitrogenase enzyme involving Fe and Mo
- H2 -> H+ : hydrogenase enzyme involving Fe and Ni
- O2 -> H2O : cytochrome C oxidase involves Fe and Cu
5) State 3 functions of metals in proteins
- Catalytic enzymes
- Regulatory
- Structural (tertiary/quarternary etc)
[Also allows interactions between metals and other biomolecules]
6) Describe 2 ways in which metal ions can be incorporated into proteins
- Folding of protein, then insertion of metal
- Metal present at start, assists in the protein folding (risk of misfolding leading to aggregation -> diseases)
7) Give 3 common ligands of metals in proteins
- Nitrogen (histidine)
- Oxygen (glutamate, aspartate)
- Sulphur (cysteine)
[Ligands of metals can bind in many different ways which affect the properties of the protein]
8) What is the ‘signature’ of metal-binding sites in proteins?
Characteristic binding patterns in a protein
9) State 4 uses of mining sequence databases
- Structural genomics (structure, function, evolution, and mapping of genomes) : search for 3D structures of metalloproteins
- Determine ligand structures
- Search for homology (shared ancestry) in sequence databases
- Find putative (generally thought to exist) metalloproteins
10) Name the 4 essential minerals (electrolytes)
Na, Mg, K, Ca
[Na has a high conc outside the cell and K has a high conc inside the cell]
11) What are the requirements for Na and K per day?
Na: 2.3g/d
K: 4.7g/d
12) State 2 types of complex Mg is involved in
- Cofactor complex (contained in every ATP complex)
- Enzyme complex
13) Describe the function of Ca in signalling and give 2 receptors it is involved with
- Intracellular regulator
- Involved with tyrosine kinase and G protein-linked receptor
[Initiates pathway for inositol biphosphate formation -> binds to endoplasmic reticulum and causes release of Ca]
- Calcium ATPase used to pump Ca out of cell
14) State the 6 essential trace metals
Mn, Co, Fe, Cu, Zn, Mo (forms cofactors with metals, e.g. pterin)
15) State cofactors formed with metals, for Co, Ni and Fe
Co: forms Vitamin B12, cobalamin (corrin)
- only 2 reactions in human metabolism - fatty acid metabolism and folate metabolism
Ni: 9 nickel enzymes known, none in humans
Fe: present in cytochromes, myoglobin and haemoglobin