The chemical components of cells Flashcards
Which are the most abundant organic molecules in living cells?
Proteins
How much dry weight do proteins account for?
40 - 70 % of dry weight
Which groups do amino acids contain?
Carboxyl (-COOH) and amino (-NH2) groups
What are the two isomeric forms of amino acids?
L and D amino acids
Which amino acids are only found in proteins?
L-amino acids.
D-amino acids are rare in nature
How can the charge on an amino acid be varied?
By changing the pH. The pH at which the amino acid is uncharged is called the isoelectric point.
How many amino acids are commonly found in proteins?
20
What are proteins made up of?
Proteins are polymers built from amino acid monomers
What determines a protein’s primary structure?
The amino acid sequence
What determines a protein’s secondary and tertiary structures?
The interaction between the various side groups of amino acids
What determines a protein’s quartenary structure?
Combining more than one polypeptide chain
Five major categories of proteins
- Structural e.g. keratin
- Catalytic e.g. enzymes
- Transport e.g. haemoglobin
- Regulatory e.g. hormone
- Protective e.g. antibodies
What are special about enzymes?
They contain an active site, to which a specific substrate can bind during catalysis
What are the common form of enzymes?
Globular
What functional groups are between the amino acid monomers in a polymer?
Condensation reaction between amino acid monomers to form peptide bonds
The structure of hemoglobin
Hemoglobin is a conjugated protein. Contains additional groups amino acids. Made up of four iron-containing organometallic complexes (heme groups_