Facts from ECB CH2, Chemical Components of Cells| 240 words
Here are facts I found interesting from the second chapter of Essential Cell Biology.
- C, H, N, and O constitute 96% of any organism’s weight.
- Typical covalent bonds are stronger than thermal energies by a factor of 100.
- In living organisms, covalent bonds are only broken when in the presence of enzymes.
- In an aqueous solution, ionic bonds are 10-1000 times weaker than the covalent bonds.
- Cell interiors are kept close to neutral pH by the presence of buffers.
Small Molecules in Cells
- Molecules with a backbone of carbon are called organic molecules.
- Cells contain four major families of small organic molecules: sugars, fatty acids, amino acids, and nucleotides.
- Here is a table summarizing the chemical composition of a bacterial cell
- Fatty acids can produce six times the number of energy per gram as glucose.
- 20 types of amino acids are commonly found in proteins.
- Proteins are 1/2 of a cell’s dry mass.
Macromolecules in Cells
- Macromolecules are 80% of a cell’s dry mass.
- Early chemists didn’t think that large molecules could exist. With its purported 700 carbon atoms, the existence of hemoglobin was deemed “very improbable” by leading chemists. Centrifuging hemoglobin revealed a single sharp band with molecular weight of 68k daltons, confirming its size.
- Enzymes recognize their substrates via noncovalent interactions.
- Proteins bind together into multiprotein complexes with noncovalent bonds.