Biochemistry: Important Macromolecules in the Human Body
The following table summarizes the following types of large, also called 'macro-', biomolecules according to their general chemical structure:
- Carbohydrates
- Lipids
- Proteins
- Nucleic Acids
- Nucleotides and related molecules
- Combinations of the above
Type / Category of Macromolecule: Functions: (... for the general case unless a specific example is stated) Type / Category of Macromolecule: |
Carbohydrates |
Ribose is important for the expression of hereditary information.
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Lipids |
Type / category of Lipid: Triglycerides
Many fats in the diet, e.g. Butter, Olive oil
Triglycerides store energy.
Type / category of Lipid: Phospholipids
Phospholipids form cell membranes.
Type / category of Lipid: Steroids
Steroids form cell membranes and synthesise hormones.
Type / category of Lipid: Prostaglandins
There are 9 classes of prostaglandins (PGA, PGB, PGC ... PGI) and individual prostaglandins denoted by subscripts e.g. PGE1.)
Prostaglandins have several functions, including:
- regulating the action of hormones
- helping the immune system
- influencing inflammatory responses
- causing contraction of smooth muscle e.g. of the uterus for labour
- contributing to production of mucus in the stomach
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Proteins |
Type / category of Lipid: Functional
Functional proteins regulate chemical reactions.
Type / category of Lipid: Structural
Structural proteins form part of tissues that provide mechanical support to the part of the body in which they are located.
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Nucleic Acids |
Deoxyribonucleic acid (DNA)
DNA is the genetic code from which all protein is synthesised.
It stores genetic information and ensures daughter cells inherit data from (hence receive the characteristics of) their parent cells.
Put simply, the purpose of DNA is to code the way proteins turn genes 'on' or 'off'.
DNA is also needed to form 'Messenger RNA' (mRNA).
RNA has many functions, including:
- carrying genetic information,
- catalysing certain biochemical reactions,
- acting as an adapter molecule in protein synthesis,
- acting as a structural molecule in cellular organelles.
This could be answered in even more detail by listing specific types of RNA with their functions, e.g.
- Messenger RNA (mRNA) - transfers genetic info from DNA to ribosomes
- Transfer RNA (tRNA) - translates genetic info from DNA to specific amino acids, i.e. specific tRNA for each amino acid.
- Ribosomal RNS (rRNA) - part of ribosome, catalytic function.
- Small Nuclear RNA (snRNA) - regulates & catalyses reactions involving mRNA
- Guide RNA (gRNA) - directs editing of RNA to specific locations.
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Nucleotides - and related molecules |
Adenosine triphosphate (ATP)
Important role in transferring energy from 'fuel' molecules to working tissues in muscle actions (contraction and relaxation): ATP --> Adenosine diphosphate (ADP) + energy + inorganic Phosphate.
Transfers energy from fuel molecules to ATP.
Nicotinic adenine dinucleotide (NAD)
Coenzyme for transfer of high-energy particles from one chemical process to another.
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Examples of Combinations of the above |
Type / category of Lipid: Glycoproteins
Glycoproteins regulate chemical reactions (i.e. they have similar functions to those of functional proteins).
Type / category of Lipid: Proteoglycans
Proteoglycans are a type of (heavily glycosylated) glycoprotein, e.g. aggrecan.
Proteoglycans are important for lubrication because they can increase the thickness of fluids.
Type / category of Lipid: Lipoproteins
Types of lipoproteins include low-density lipoproteins (LDLs), high-density lipoproteins (HDLs) and very low-density lipoproteins (VLDLs).
Lipoproteins transport lipids in blood.
Type / category of Lipid: Glycolipids
Cerebrosides (in the myelin sheaths of nerve fibres), e.g. glucocerebrosides and galactocerebrosides.
Glycolipids are component parts of the (non-rigid) phospholipid bilayer that forms cell membranes.
Type / category of Lipid: Ribonucleoproteins
e.g. ribosomes, small nuclear ribonucleoproteins (snRNPs), heterogeneous nuclear ribonucleoproteins (hnRNPs), and the enzyme telomerase.
Ribonucleoproteins have many enzyme-like functions, e.g. slicing mRNA.
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This information about biochemistry might be useful to students of the human body. It also applies to many other (non-human) species.
Example Study Question:
This page includes several possible answers to a test or exam question such as:
List 10 macromolecules (or types of
macromolecules) produced by the human body and
give one example of the functions of each. Include
in your answer at least one type of
macromolecule from each of the following
three categories:
- Carbohydrates
- Lipids
- Nucleic Acids.
Lists and definitions in textbooks vary. If this topic forms part of your syllabus check the level of detail required for your particular course. (You can find out by asking your teacher or course leader.)
Example Answer: Sufficient information is included above. Click here for possible answers.
