Syllabus Edition

First teaching 2014

Last exams 2024

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Digestion & Absorption (DP IB Biology: SL)

Exam Questions

3 hours35 questions
1a1 mark

The diagram below shows a structure found in the small intestine.

iwYCrqY7_e-1a

Identify this structure.

1b2 marks

Identify structures B and in the diagram in part a).

1c2 marks
(i)

Identify structure A in the diagram in part a).

[1]

(ii)

State one function of structure A.

[1]

1d2 marks

The products of digestion are absorbed by means of different membrane transport mechanisms.

List two mechanisms by which the products of digestion can be absorbed.

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2a1 mark

The following diagram illustrates the steps involved in the digestion of starch.

5Qr2xt3N_e-2a

State the name of product 1.

2b2 marks

Enzyme X is responsible for completing the digestion of starch.

(i)

State the name of enzyme X.  

[1]

(ii)
Identify the type of bond that is broken by enzyme X to form product 2.

[1]

2c2 marks

The digestion of starch occurs in various parts of the digestive system.

Identify two parts of the digestive system where starch digestion occurs.

2d1 mark

Product 2 represents the final product of starch digestion.

Identify product 2.

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3a
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2 marks

A group of students set up an experiment to investigate membrane permeability using dialysis tubing. The diagram below shows their experimental set-up.9eqyGTS3_e-3a

The students measured the mass of the dialysis tubing and its contents at the start of the experiment (0 minutes) and then again at 5 minute time intervals for 30 minutes. Their results are shown in the following table.

Time / min Mass / g
0 15.4
5 15.8
10 16.1
15 16.5
20 16.9
25 17.2
30 17.6

Calculate the increase in mass. Show your working.

3b1 mark

Using the results in part a), state the direction in which water moved during the experiment.

3c2 marks

Dialysis tubing is often used to model digestion and absorption in the small intestine.

Describe one characteristic of dialysis tubing that makes it suitable for this purpose.

3d1 mark

The students also tested the water surrounding the dialysis tubing for the presence of glucose and starch throughout the investigation.

State their expected results.

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4a1 mark

The following micrograph shows the different layers of the small intestine.

ALC4yyMb_e-4a

Image courtesy of Juan Carlos Fonseca Mata. Licensed under Creative Commons Attribution-Share Alike 4.0 International licence. Reused and distributed under conditions found at: https://creativecommons.org/licenses/by-sa/4.0/

Layer Z is responsible for peristalsis in the small intestine.

State one function of peristalsis in the small intestine.

4b3 marks

Layer Z contains two layers of smooth muscle.

(i)

Identify the two layers of smooth muscle.

[1]

(ii)

State the role of each muscle layer.

[2]

4c2 marks

Layer X is responsible for absorption.

State what is meant by the term 'absorption'.

4d2 marks

Layer Y contains important structures that facilitate transport of absorbed substances.

(i)

Identify layer Y.

[1]

(ii)

Identify two structures found in layer Y that facilitate the transport of absorbed substances.

[1]

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5a3 marks

One mark is available for clarity of communication throughout this question.

Absorption of digested food molecules, vitamins, and minerals occurs in the ileum.

State three adaptations of the ileum that increases the surface area for absorption.

5b5 marks

Draw a labelled diagram of the digestive system.

5c5 marks

Outline the roles of pancreatic juice. Include the names of relevant enzymes in your answer.

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1a1 mark

The diagram below shows part of the human digestive system. The different organs are labelled H - M.

screenshot-2023-07-12-at-3-40-48-pm

Give the letter of an organ where peristalsis does not occur.

1b2 marks

Outline how peristalsis ensures one way movement of food through the alimentary canal.

1c2 marks

Name organ L in the diagram above, and identify a digestive enzyme that it produces.

1d3 marks

The glucose concentration in blood rises after eating a meal that contains carbohydrates. The increase in glucose concentration occurs at a slower rate if the carbohydrate ingested is starch, rather than sucrose.

Explain why this is.

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2a1 mark

The diagram shows some acinar cells in the pancreas.

GO3kO8iK_1

Identify the structures labelled X and state what is contained within these structures.

2b2 marks

Pancreatitis is a medical condition that can lead to the pancreatic duct becoming blocked. It can also cause protein-digesting enzymes to be released into the bloodstream.

Suggest one reason why this might be harmful.

2c2 marks

The image below shows an investigation carried out into the effect of pH on the activity of amylase enzymes.

2SlA-Jsn_2

In the investigation, two sections of dialysis tubing were set up containing the following mixtures:

Tube A

Tube B

  ●      1 ml of 1% amylase solution

●      10 ml of 1% starch solution

●      5 ml of pH 2 buffer solution

   ●      1 ml of 1 % amylase solution

●      10 ml of 1% starch solution

●      5 ml of pH 8 buffer solution

After 30 minutes, the substances were tested using iodine solution.

Using the information given, deduce the results that would be expected from the mixtures tested in tube A.

2d2 marks

Suggest how tube B provides an accurate representation of absorption in the small intestine.

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3a1 mark

The diagram below illustrates the co-transport mechanism for the absorption of amino acids into the blood by a cell lining in the small intestine.

76plO4WY_3 Identify the substance X on the diagram.

3b3 marks

Use the diagram in part (a) and your knowledge of the co-transport mechanism, to explain why cells in the small intestine contain a large number of mitochondria.

3c4 marks

Describe the role that enzymes play in the digestion and complete breakdown of starch into glucose.

3d1 mark

State the property of glucose which prevents it from passing into the blood by simple diffusion.

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4a2 marks

Bile salts bind to fat droplets and break them down into smaller fat droplets.

Explain how this process makes lipid digestion more efficient.

4b1 mark

The diagram below outlines the mechanism of lipid digestion and absorption.

screenshot-2023-07-12-at-4-44-25-pm

State what type of cell A is

4c4 marks

A student wanted to investigate the breakdown of triglycerides in cow milk by human lipase at 20 °C.

They recorded the pH of a sample of cow’s milk before and after adding human lipase, using a pH meter to measure the pH. Their results are shown in the graph below.

screenshot-2023-07-12-at-4-48-56-pm

Describe and explain the changes in pH after human lipase is added.

4d2 marks

The student carried out his experiment at a controlled temperature of 20 °C. They repeated the experiment at 25 °C.

Draw a line on the graph in part (c) to show the results you would expect at 25 °C.

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5a4 marks

One mark is available for clarity of communication throughout this question.

Compare and contrast the action of endopeptidases and exopeptidases in the small intestine.

5b7 marks

Explain how the small intestines are adapted to maximise absorption.

5c4 marks

Outline the structure and function of the following layers of the wall of the small intestine:

  • Muscle layer
  • Submucosal layer

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1a
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2 marks

Washing powders often contain different types of enzymes that break down substances in stains. An investigation was carried out into washing powder that contained enzymes and washing powder that did not contain enzymes. The graph below shows the results of this investigation.

6-1-hard-q1a

Some of the substances that cause food stains are large insoluble proteins. 

Explain how washing powder containing enzymes would be able to remove these stains.

1b
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3 marks

The manufacturers of the washing powder containing enzymes claimed that their washing powder was more effective at removing tough stains compared to the washing powder without enzymes.

Based on the results of the investigation in part a), evaluate the claim of the manufacturers.

1c
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1 mark

The investigation at part a) was carried out at 40 °C.

Suggest a reason for this.

1d
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3 marks

The investigation was repeated at a temperature of 85 °C.

Predict, with a reason, the expected results from this investigation.

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2a
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2 marks

The following diagram shows the absorption of amino acids from the small intestine into the blood.

6-1-hard-q2a

The absorption of amino acids involves the process of facilitated diffusion.

Explain where this occurs in the diagram.

2b
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2 marks

Cyanide is a potentially deadly chemical that inhibits the functioning of mitochondria.

(i)

Suggest the effect that cyanide would have on the concentration of sodium ions inside the intestinal epithelial cells shown in part a).

[1]

(ii)

Explain your answer to part i).

[1]

2c
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3 marks

Suggest, with a reason, the effect that cyanide would have on the absorption of amino acids.

2d
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1 mark

Explain why amino acids cannot be absorbed by simple diffusion.

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3a
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2 marks

Coeliac disease is an autoimmune disorder that occurs in some people when they consume gluten, a type of protein found in certain grains. During an autoimmune disorder the immune system launches an attack on healthy body tissue which involves lymphocytes.

The following diagram compares the lining of the small intestine of a healthy person and a person suffering from coeliac disease.7vNW9Erc_h-3a

Based on the information provided, explain how coeliac disease will affect the absorption of nutrients.

3b
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3 marks

Suggest how the immune system would respond to the presence of gluten proteins.

3c
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3 marks

The following graph shows the number of people at a hospital diagnosed with coeliac disease according to their age group.

QoxoAj6B_h-3c

Describe what the data show about age and number of cases of coeliac disease.

3d
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1 mark

Suggest an explanation for the observed prevalence of coeliac disease across different age groups shown in part c).

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4a
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3 marks

People suffering from stomach cancer can undergo surgery to remove a part of their stomach. This type of surgery is known as a gastrectomy and can result in the patient developing a set of symptoms known as 'dumping syndrome'.

Usually the stomach will slowly release small amounts of partially digested food into the small intestine over a period of several hours, but in patients suffering from dumping syndrome large amounts of poorly digested food are released into the small intestine in a short period of time after a meal. This poorly digested food tends to be high in dissolved nutrients such as sugars.

(i)

One symptom of dumping syndrome is a large volume of fluid in the small intestine.

Explain why this is the case.

[2]

(ii)

Suggest one possible symptom that might result from this excess of fluid.

[1]

4b
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2 marks

Patients will often suffer from nutrient deficiencies after developing dumping syndrome.

Suggest a reason for this.

4c
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1 mark

Up to a third of dumping syndrome patients suffer from a form of the condition known as late dumping syndrome. These patients will experience symptoms 1-3 hours after eating due to the effects of the hormone insulin. 

Suggest why these symptoms would arise 1-3 hours after eating.

4d
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3 marks

One of the symptoms of late dumping syndrome is fatigue.

Using information provided in part c), explain why people suffering from late dumping syndrome would feel fatigued.

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5a
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4 marks

One mark is available for clarity of communication throughout this question.

Compare and contrast the process of peristalsis in the oesophagus and the small intestine.

5b
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7 marks

The products of lipid digestion are absorbed by the villi of the small intestine.

Outline the process of lipid absorption.

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