Chemical Digestion (Cambridge O Level Biology)

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Chemical Digestion

Stages of food breakdown

  • Food taken into the body goes through 5 different stages during its passage through the alimentary canal (the gut):
    • Ingestion - the taking of substances, e.g. food and drink, into the body through the mouth
    • Mechanical digestion - the breakdown of food into smaller pieces without chemical change to the food molecules
    • Chemical digestion - the breakdown of large, insoluble molecules into small, soluble molecules
    • Absorption - the movement of small food molecules and ions through the wall of the intestine into the blood
    • Assimilation - the movement of digested food molecules into the cells of the body where they are used, becoming part of the cells
    • Egestion - the passing out of food that has not been digested or absorbed, as faeces, through the anus
  •  The role of chemical digestion is to produce small soluble molecules that can be absorbed

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Phil

Author: Phil

Expertise: Biology

Phil has a BSc in Biochemistry from the University of Birmingham, followed by an MBA from Manchester Business School. He has 15 years of teaching and tutoring experience, teaching Biology in schools before becoming director of a growing tuition agency. He has also examined Biology for one of the leading UK exam boards. Phil has a particular passion for empowering students to overcome their fear of numbers in a scientific context.