Lecture Four - The main classes of macromolecules Flashcards
What are true four main types of macromolecules?
Nucleic acids Carbohydrates Proteins Lipids
Describe nucleic acids.
Reside mainly in the nucleus, but also sometimes in the cytosol.
DNA:
Deoxyribonucleic acid - giant protein that carries the genetic code for maing proteins.
RNA:
Ribosnucleic acid - several different types of molecule, involved in protein synthesis.
Describe carbohydrates.
General formula is (CH2O)n
Carbohydrates are saccharides which are sugars.
Simple sugars = monosaccharides.
Short chains = oligosaccharides.
Long chains = polysaccharides.
Draw the chemical structure of glucose when it turns into a ring structure.
What is the difference between a beta and an alpha linkage?
What is a glycosidic bond? Draw one.
A glycosidic bond is the bond holding two glucode molecules together.
Describe and draw the difference between branched and unbranched carbohydrates.
Branched:
Can not be packed as closely together.
Therefore have more sites for enzymes to attach.
Therefore are easier to breakdown.
Unbranched:
Pack more tightly.
Fewer enzyme binding sites.
Less easy to break down.
What is the difference between starch and cellulose?
How do polysaccharides differ from one another?
Chain length.
Nature of monosaccharides (branching).
Degree of branching.
Linkage between subunits (alpha or beta).
Describe proteins.
Linear hains of amino acids covalently bonded togehter by condensation or dehydration reactions to give a peptide bond.
Draw how dehydration/condensation reactions occur between amino acids.
Describe the structures of proteins.
Primary structure:
The sequence of amino acids.
Secondary structure:
Rotation about the peptide bond.
Alpha helices and beta pleated sheets.
Maintained by H bonds.
Tertiary structure:
Ways in which sections of the secondary structures are folded up relative to each other to give the 3D structure of the polypeptide chain.
Maintained by weak intermolecular bond interactions.
Quarternary structure:
Multiple tertiary structures jointed together.
Proteins larger than 40,000 daltons usually have more than one tertiary structured protein.
E.g. Haemoglobin has four tertiary structures joined together.
Describe lipids.
Water insoluble molecules with a range of different structures and functions.
1) Storage of large amounts of energy
2) Majory component of cell membranes.
Phospholipid forms a bylayer with hydrophillic heads and hydrophobic tails.
