T1.3.4 The human digestive system Quiz: KS3 Biology, Unit 1

The 20 questions

1. Where does mechanical digestion begin?

   • In the mouth, where teeth break food into smaller pieces
   • In the small intestine, where bile breaks food down
   • In the stomach, where acid breaks food down
   • In the large intestine, where bacteria break food down

2. Which enzyme starts the digestion of carbohydrates in the mouth?

   • Lipase
   • Pepsin
   • Amylase
   • Protease

3. Which organ produces hydrochloric acid and the enzyme pepsin?

   • The liver
   • The pancreas
   • The stomach
   • The small intestine

4. Which enzyme breaks down proteins into amino acids?

   • Amylase
   • Lipase
   • Bile
   • Protease

5. Which enzyme breaks down fats into fatty acids and glycerol?

   • Pepsin
   • Lipase
   • Protease
   • Amylase

6. Where is bile produced?

   • The stomach
   • The large intestine
   • The pancreas
   • The liver

7. What is the role of bile in digestion?

   • It digests proteins into amino acids
   • It absorbs water in the large intestine
   • It breaks large fat droplets into smaller ones
   • It kills all bacteria in the stomach

8. Which structure gives the small intestine a large surface area for absorption?

   • The oesophagus
   • Villi
   • The anus
   • The gall bladder

9. Why is the wall of a villus thin?

   • To produce digestive enzymes that break down the food in the gut
   • To allow digested food to diffuse quickly into the blood
   • To make it stronger so it can resist the pressure of food
   • To stop digested food from entering the blood and being wasted

10. What is the function of the large intestine?

    • To absorb water from undigested food
    • To store food before it is digested
    • To digest starch into simple sugars
    • To produce bile to emulsify fats

11. What is the oesophagus?

    • The gland that makes insulin in the body
    • The tube that connects the mouth to the stomach
    • The organ that stores bile before it enters the gut
    • The muscle that moves food along the lower gut

12. Which organ stores bile before it enters the small intestine?

    • The stomach
    • The kidney
    • The pancreas
    • The gall bladder

13. Which organ produces amylase, protease and lipase?

    • The liver
    • The pancreas
    • The large intestine
    • The stomach

14. What do enzymes do during digestion?

    • They are a type of food that the body digests for energy
    • They are used up completely in each reaction and must be replaced
    • They act as biological catalysts that speed up the breakdown of food
    • They work only in the mouth and stop once food reaches the stomach

15. Why does the stomach need a very acidic environment?

    • To absorb water into the blood and remove waste
    • To produce bile and break down fats in the stomach
    • To make food sweeter and easier to swallow
    • To activate pepsin and kill many bacteria in food

16. Which sequence correctly shows the path of food through the gut?

    • Oesophagus, mouth, stomach, large intestine, small intestine
    • Mouth, stomach, small intestine, oesophagus, large intestine
    • Mouth, oesophagus, stomach, small intestine, large intestine
    • Mouth, stomach, oesophagus, large intestine, small intestine

17. What is the role of the liver in digestion?

    • It produces bile, which is stored and released into the gut
    • It produces pepsin, which is stored and released into the stomach
    • It absorbs digested food and stores it as glycogen in the blood
    • It produces amylase, which is released into the mouth to digest food

18. Which part of the digestive system absorbs most of the digested food into the blood?

    • The large intestine
    • The mouth
    • The stomach
    • The small intestine

19. Why does pepsin work in the stomach rather than in the mouth?

    • Pepsin is only made in the mouth and never reaches the stomach
    • Saliva destroys pepsin before it can reach the stomach
    • Pepsin works best in the stomach's acidic conditions
    • Pepsin needs the large intestine to be fully active

20. Which organ releases digestive enzymes into the small intestine?

    • The pancreas
    • The oesophagus
    • The liver
    • The stomach

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