Biomolecules Flashcards
Example of amino acid
Glycine (Gly)
Note : R=H
An amino acid consists of
A carbon atom which is attached to 4 groups:
- an amino group (NH2)
- a carboxyl group (COOH)
- a hydrogen atom (H)
- a side chain (R)
Primary structure of a protein
Sequence of amino acids
Secondary structure of a protein
Segments of the polypeptide chain at coiled it folded
What causes secondary structure?
Hydrogen bonding at regular intervals between a weakly positive H of NH and a weakly negative O of CO
Alpha helix
A spiral held together by hydrogen bonding at every 4th amino acid e.g fibrous proteins - alpha-keratin
Beta pleated sheet
Two regions of a polypeptide chain lie parallel to each other. Hydrogen bonding occurs between different parts of the polypeptide. E.g globular proteins - lysozyme
Tertiary structure of proteins
Irregular folding of protein structure due to bonding between side chains (R groups) of the amino acids. Bonding includes H-bonding, ionic bonding, hydrophobic interactions, van der Waals forces, and covalent bonding between disulfide bridges (-SH)
Quaternary structure of protein
When a protein consists of two or more polypeptide chains e.g haemoglobin. Bonding includes H-bonding, ionic bonding, hydrophobic interactions, van der Waals forces, and disulfide bridges
Chaperonin
Proteins that assist in the proper folding of other proteins. Keep the new polypeptide separated from ‘bad influences’ in the cytoplasm while it folds
Techniques for studying protein structure
X-Ray crystallography , NMR spectrophotometry, bioinformatics
Name the 8 types of protein
1) structural e.g collagen in connective tissue
2) storage e.g casein in milk provides amino acids for baby mammals
3) transport e.g haemoglobin
4) hormonal e.g insulin regulates blood sugar
5) receptor e.g membrane of nerve cells detect chemical signals
6) contractile e.g myosin moves muscles
7) defensive e.g antibodies attract bacteria and viruses
8) enzymatic e.g digestive enzymes catalyse the hydrolysis of the polymers in food
Function of nucleic acids
Enable living organisms to reproduce their complex components from one generation to the next
Nucleoside
Portion of nucleotide without phosphate
Functions of carbohydrates
- Energy stores e.g glycogen
- Structural elements e.g cellulose
- Cell-cell recognition e.g glycoproteins
