BIOMOLECULES [TOPIC GUIDE]
Introduction to biomolecules
Biomolecules is a core JC1 topic in H2 BIO A levels. This topic explores the 3 most important biomolecules that makes up a cell: carbohydrates, proteins and lipids. You will learn about the monomers such as amino acids, glucose, glycerol and fatty acids as well as their polymeric structure and functions. This includes, cellulose, amylose, amylopectin, glycogen, phosphopipids, triglyceride, haemoglobin, collagen as well as GPCR.
A selection of materials for biomolecules
Most common phrasing errors made by students during exams
Cellulose is soluble and linear
Haemoglobin has 2β and 2α chains
Collagen comprises of a triple helix
Phospholipids are hydrophobic molecules
Cellulose is a protein and collagen is a polysaccharide
Cellulose has β1-4 whereas starch have α1-6 glycosidic bonds
Chains of cellulose are cross-linked by covalent hydrogen bonds
Secondary structures of proteins results from hydrogen bonds between O atom of the -CO and H atom of the -NH groups
Very often questions asks to compare 2 molecules:
Give point to point comparison i.e. 1 point in 1 sentence
What does the question want? Structure? Function? Reference to diagram? Relate structure to function?
If its structures, monomers and bonds formed between monomers are easy points to use
Don’t write vague differences e.g. collagen is a protein
Don’t include non-structural differences e.g. collagen forms connective tissues in animals
Careful not to compare different levels of organization e.g. comparing a single cellulose chain to a single collagen polypeptide chain
Do not confuse collagen and cellulose!
Haemoglobin best describes all levels of protein structures so use it whence you can
Did the question ask for a biomolecule’s structure? Function? Or structure relating to function?
Expect to know various food tests, procedures and results, questions can appear even in papers 1, 2 as well as 3
When describing dehydration reactions, include details of H from one monomer and OH of another monomer in forming water
Protein structures at tertiary and quaternary level are formed by the same 4 types of bonds BUT how the bonds form must be clarified
BYang’s tough questions bank
Fizzy (carbonated) drinks are increasingly used to tenderize tough cuts of meat. Suggest a mechanism to explain the phenomenon. [4m. Created 210312]
Questions and other matters
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