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Life Processes in Animals

Saliva and starch

Rice has starch, not sugar. Starch is the main food part in rice and roti. Yet a long chew can make rice taste sweet. Why?

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The idea

Saliva is a digestive juice in the mouth. It breaks starch into sugar.

Chewed rice tastes sweet because saliva turns its starch into sugar. Teeth crush food into fine pieces.

Iodine turns blue-black when starch is there. A teacher does this test.

A piece of roti goes into the mouth.
Step 1 of 4
  1. A piece of roti goes into the mouth.
  2. Teeth crush it into smaller pieces.
  3. Saliva starts working on the starch inside it.
  4. Starch broken into sugar tastes sweet.

Saliva breaks starch into sugar. Iodine turns blue-black when starch is there.

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This track

  1. 0 Start here
  2. 1 Digestion, absorption and egestion
  3. 2 One path, and a job at every stop
  4. 3 Saliva and starch
  5. 4 Ruminants and birds
  6. 5 Checkpoint: what a body does with food
  7. 6 Breathing is not respiration
  8. 7 Lungs, gills and moist skin
  9. 8 Getting food and oxygen around
  10. 9 What a body cannot use has to leave
  11. 10 The path of air
  12. 11 How the chest moves
  13. 12 Gases swap at the alveoli
  14. 13 Villi give food a way in
  15. 14 Checkpoint: the breathing path, the chest and villi
  16. 15 The big picture
  17. 16 Track quiz

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