I/GCSE Biology - The food groups

In I/GCSE Biology, we should acknowledge the functions of different food groups below.

• Lipids (fats & oils) : Used as a long-term energy store (much easier to store than carbohydrates). Also have a role in protection and insulation

• Carbohydrates : Made from single sugars or chains of sugars. They are used in respiration to provide energy

• Proteins : Broken down into amino acids, which our body absorbs and assembles into new proteins. The proteins are used for growth and repair

• Fibre :  Regulates bowel movement. Sloughs off old lining of intestine.

• Water :  Essential as a solvent for chemical reactions (e.g. cytoplasm), heat loss (e.g. transpiration), transport (e.g. blood) etc.

• Vitamins and Minerals : Essential for the normal function of some enzymes and proteins e.g. Fe²⁺ is an essential part of Haemoglobin and Mg²⁺ is part of Chlorophyll

The main food groups are carbohydrates, lipids and proteins. We are required to know all three groups are made from smaller molecules in I/GCSE Biology.

• Carbohydrates are large molecules made from one or more sugars (e.g. both Starch and Glycogen are both polymers of Glucose)

Diagram 1 : The structure of cyclic monosaccharide

• Proteins are polymers of Amino Acids

Diagram 2 : Four levels of protein structure

• Lipids are made from one glycerol molecule and three fatty acid molecules joined together.

Diagram 3 : The structure of triglyceride

That's the end of the topic!

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Drafted by Joey (Biology)

Reference:

https://getrevising.co.uk/resources/biology_revision_notes8

https://courses.lumenlearning.com/microbiology/chapter/carbohydrates/

https://courses.lumenlearning.com/microbiology/chapter/carbohydrates/