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Biology

GCSE · Edexcel

QuestionsFlashcards

Photosynthesis
Plant Structure
Transport in Plants
Plant Hormones
- Plant Hormones & Growth
  7
- Using Plant Hormones Commercially
  7

Transport in Animals
- The Need for Transport
  7
- Factors Affecting the Rate of Diffusion
  7
Respiration
- Respiration
  6
- Practical: Investigating Respiration
  5
Gas Exchange
Circulatory System
- The Blood & Blood Vessels
  6
- The Circulatory System
  8

Practical: Food Tests Flashcards

All 6 cards in this deck

What is the food test for starch and its positive result?: Add iodine solution; it turns from orange-brown to blue-black.
What is the food test for reducing sugars and its positive result?: Add Benedict's solution and heat in a water bath; it turns from blue to brick-red (through green, yellow, orange).
What is the food test for protein and its positive result?: Add Biuret solution; it turns from blue to purple/lilac.
What is the emulsion test for fats and its positive result?: Shake the sample with ethanol, then add water; a cloudy white emulsion forms.
A food sample turns iodine blue-black and Biuret purple. Which food molecules does it contain?: Starch and protein.
True or false? A Benedict's test that stays blue after heating shows no reducing sugar is present.: True. A colour change to green, yellow, orange or brick-red is needed for a positive result.