The Need for Food

Click on a number in the grid to see the clue or clues for that number.
Complete the crossword, then click on "Check" to check your answer. If you are stuck, you can click on "Hint" to get a free letter.

 1   2                3    4    
                    
5                6        
                    
7                  8      
            9          
  10        11              
                    
       12               
 13                     
           14           
     15                 
                    
   16   17         18           
                    
                    
 19                     
                    
   20                   
                    

Across:

1. Ring of muscle surrounding the entrance to and the exit from the stomach; on contraction, it closes the opening. (9)
3. General name for a tube that carries a secretion given out by an organ or gland. (4)
5. Energy-rich food such as sugar, starch or glycogen whose molecules contain the chemical elements carbon, hydrogen and oxygen. (12)
7. Movement of end products of digestion through the inner lining of the gut wall into the bloodstream. (10)
9. Intermediate product of protein digestion. (7)
10. Building blocks of protein molecules and the end products of protein digestion. (5,5)
12. Complex carbohydrate composed of glucose molecules; stored in the human liver. (8)
13. One of many finger-like projections that increase the absorbing surface of the small intestine; contains blood capillaries and a lacteal to absorb end products of digestion. (6)
15. Enzyme present in saliva and pancreatic juice that promotes the digestion of starch to maltose. (7)
16. Reducing sugar that is the building block of complex carbohydrates such as starch and cellulose and the end product of their digestion. (7)
18. Substance made in the liver that converts large droplets of fat to small droplets of fat. (4)
19. Type of building block of fat molecule and an end product of fat digestion. (5,4)
20. Liquid containing amylase enzyme produced by the salivary glands. (6)

Down:

2. Wavelike motion of gut wall caused by alternate contraction and relaxation of muscle; moves food along alimentary canal. (11)
4. Type of tooth that is pointed used to tear food; used by carnivores to stab and grip prey. (6)
6. Type of protease enzyme present in juice that promotes the digestion of protein to peptides. (7)
8. Enzyme present in pancreatic juice that promotes the digestion of fat. (6)
11. Complex carbohydrate composed of glucose molecules linked into fibres that make up plant cell walls. (9)
14. Type of animal whose dentition is suited to a diet of plant material only. (9)
17. Tiny lymphatic vessel inside a villus that absorbs the end products of fat digestion. (7)