7.1 Human Diet & Digestion

Below is a list of chemical reactions that occur during digestion.

1. Protein → amino acids
2. Starch → maltose
3. Lipids → fatty acids + glycerol
4. Maltose → glucose

Which of the chemical reactions above might occur in the duodenum?

Which of the following shows the correct role of a substance made during digestion?

	substance	made by	effect
A	trypsin	stomach	digests proteins into amino acids
B	bile	gallbladder	neutralising acidic mixture of food entering the duodenum from the stomach
C	gastric juice	stomach	denaturing enzymes in harmful microorganisms and optimising pH for pepsin activity
D	bile	liver	neutralising alkaline mixture of food entering the duodenum from the stomach

Extended only

The diagram below shows the activity of salivary amylase on a starch molecule.

 

Which of the following is not a function of salivary amylase?

The diagram below shows the organs of the digestive system, including the alimentary canal and accessory organs.

Where are most of the digestive lipase enzymes made in the body?

Which of the following is a correct cause and effect?

	deficiency	cause	effect
A	iron	diet deficient in red meat, leafy green vegetables and liver	brittle bones (rickets)
B	iron	lack of sunlight, fish and eggs	anaemia - tiredness and weakness due to not enough oxygen being delivered to tissues
C	vitamin D	lack of sunlight	brittle bones (rickets)
D	vitamin D	diet deficient in red meat, leafy green vegetables and liver	anaemia - tiredness and weakness due to not enough oxygen being delivered to tissues

Which of the following descriptions are correctly matched to the different stages of food breakdown?

	absorption	assimilation	egestion
A	small soluble food molecules move into the bloodstream	small soluble food molecules cross the cell membrane of cells	excretion of undigested or unabsorbed food through the anus
B	small soluble food molecules move into the bloodstream	small soluble food molecules cross the cell membrane of cells	passing out of undigested or unabsorbed food through the anus
C	small soluble food molecules cross the cell membrane of cells	small soluble food molecules move into the bloodstream	passing out of undigested or unabsorbed food through the anus
D	small soluble food molecules cross the cell membrane of cells	small soluble food molecules move into the bloodstream	excretion of undigested or unabsorbed food through the anus

Extended only

Which of the following could be the correct effect and explanation of a disease that results in a reduced number of villi in the small intestine?

	effect	explanation
A	weight gain	reduced absorption of digested food molecules
B	weight gain	reduced digestion of maltose to glucose, less glucose absorbed
C	weight loss	reduced lipid digestion and absorption
D	weight loss	reduced absorption of digested food molecules

Extended only

The diagram below shows a villus.

In which vessel would the concentration of fatty acids be highest?