Biology·Organisation & maintenance · NSSCO 3.4
Biological molecules & food tests
Narrated lesson · press play
The building blocks of life — carbohydrates, proteins and fats — how big molecules are built from small ones, the structure of DNA, and the five chemical tests that reveal what a food contains.
What you'll learn in this lesson
By the end you should be able to (NSSCO Biology 3.4):
- Describe the synthesis of large molecules from basic units (sugars→starch/glycogen; amino acids→proteins; fatty acids + glycerol→fats)
- Outline the roles of carbohydrates, fats and proteins; and water as a solvent
- Explain that the sequence of amino acids gives a protein its shape
- Describe the structure of DNA: a double helix with bases pairing A–T and C–G
- Describe the food tests: iodine (starch), Benedict's (reducing sugar), biuret (protein), ethanol (fats), DCPIP (vitamin C)
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Hands-on lab
Run the five food tests in the 3D lab