1 markWhich of the following is a correct function of bile?
To emulsify proteins
To neutralise the alkaline conditions of food entering the duodenum
To provide enzymes for the digestion of lipids
To increase the surface area of lipids for digestion
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1 markThe diagram below shows part of the human digestive system.
In which structure is most of the water from food absorbed?
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1 markThe diagram below shows four different types of human teeth.
Which teeth would be used to grind and chew food?
1 and 2
1 and 3
2 only
2, 3 and 4
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1 markWhich of the following best describes the function of vitamin D in a human?
Vitamin D forms an essential part of collagen protein which is the main component of skin, hair and nails.
Vitamin D is needed for strong bones and teeth and a deficiency may lead to osteoporosis later in life.
Vitamin D assists with the absorption of calcium and is therefore needed to build strong bones and teeth.
Vitamin D is an important component of haemoglobin which is needed for the transport of oxygen to the cells.
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1 markWhich of the following is not an example of physical digestion?
Breaking food up into smaller pieces by chewing it.
Starch being broken down into glucose molecules.
Food being churned when the muscles in the stomach lining contracts.
Bile breaking large fat droplets up into smaller ones during emulsification.
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1 markThe diagram below shows the organs of the digestive system.
In which organs does the digestion of proteins take place?
W and Y
W and Z
Z only
W and X
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1 markWhich 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 |
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1 markWhich 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 |
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1 markWhich 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 |
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1 markThe diagram below shows a villus.
In which vessel would the concentration of fatty acids be highest?
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1 markA student ate a meal which contained a type of biomolecule, X.
The digestion of biomolecule X started in the mouth, and finished in the duodenum.
What is the product of the digestion of biomolecule X?
Amino acids
Protein
Glucose
Starch
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1 markBelow is a list of chemical reactions that occur during digestion.
Protein → amino acids
Starch → maltose
Lipids → fatty acids + glycerol
Maltose → glucose
Which of the chemical reactions above might occur in the duodenum?
1, 3 and 4
4 only
2, 3 and 4
All 4
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1 markWhich 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 |
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1 markThe diagram below shows the activity of salivary amylase on a starch molecule.
Which of the following is not a function of salivary amylase?
Increasing the rate of breakdown of starch molecules
Increasing the rate of starch breakdown into maltose molecules
Breaking a large insoluble molecule into smaller soluble molecules
Increasing the rate of starch breakdown into glucose molecules
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1 markThe 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?
2 only
4 only
3 and 4
1 and 4
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