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A healthy digestive system The diagram shows the digestive system of a human - Edexcel - GCSE Biology - Question 4 - 2014 - Paper 1
Question 4
A healthy digestive system The diagram shows the digestive system of a human. (a) Describe the role of the mouth in digestion. (2) (b) Villi are structures in t... show full transcript
Worked Solution & Example Answer:A healthy digestive system The diagram shows the digestive system of a human - Edexcel - GCSE Biology - Question 4 - 2014 - Paper 1
Step 1
Describe the role of the mouth in digestion.
Answer
The mouth plays a crucial role in digestion in several ways:
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Mechanical Breakdown: The teeth chop, cut, and grind food into smaller pieces, increasing the surface area for enzymes to act upon.
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Chemical Digestion: Saliva introduces enzymes, such as amylase, which begins breaking down carbohydrates (specifically starch) into simpler sugars like glucose.
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Moistening the Food: Saliva also moistens and lubricates the food, making it easier to swallow.
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Formation of Bolus: The muscles of the tongue help form the chewed food into a ball (bolus) which is then pushed to the back of the throat for swallowing.
Step 2
Which one of the statements about villi is true?
Answer
The correct answer is:
C The capillary network in the villi have a large surface area.
This statement is true because the structure of the villi is designed to maximize the absorption of nutrients by providing a large surface area in contact with digested food.