Practice 6.1 Digestion and absorption with authentic IB Biology exam questions for both SL and HL students. This question bank mirrors Paper 1A, 1B, 2 structure, covering key topics like cell biology, genetics, and ecology. Get instant solutions, detailed explanations, and build exam confidence with questions in the style of IB examiners.
Paper
Level
Question 1
HLPaper 1A
The graph shows the amounts of two substances present in food ingested by a healthy person as it moves along the gut.
Which substances could X and Y be?
Question 2
SLPaper 2
The structure of part of the digestive system is shown in the diagram below. 
[Source: https://wccyusoueahdpdicsyrg.supabase.co/storage/v1/object/public/question-images/images/69c87bb4-31dd-4a17-a292-cd2edda2d48f.jpg Created by Wikipedia user: Madhero88.]
1.[1]
Label the diagram to show the structure that is involved in digestion of proteins in acid conditions (using the letter A).
2.[1]
Label the diagram to show the structure where most absorption of water to prevent dehydration occurs (using the letter B).
3.[1]
Label the diagram to show the structure where most absorption of nutrients occurs (using the letter C).
4.[2]
Explain how the structure of veins is adapted to their function.
5.[2]
Cells defend the body against pathogens. Outline how some of these cells ingest pathogens in the blood and in body tissues.
Question 3
SLPaper 1A
What is the importance of excretion to a living organism?
Question 4
HLPaper 1A
Where does the digestion of polypeptides start in humans?
Question 5
HLPaper 1A
Which gas produces most of the bubbles in bread dough?
Question 6
SLPaper 1A
Where in the human body is lipase produced?
Question 7
HLPaper 2
1.[4]
List the general functions of non-membrane proteins.
2.[6]
Outline the digestion, absorption and assimilation of proteins in humans.
3.[6]
Actin and myosin are two proteins found in muscles. Explain how skeletal muscle contracts, including the interaction of these proteins.
Question 8
SLPaper 2
1.[4]
Outline the role of condensation and hydrolysis in metabolic reactions involving carbohydrates.
2.[5]
Metabolic reactions are catalysed by enzymes. Explain how enzymes catalyse reactions and how a change in pH could affect this.
3.[6]
Describe the digestion of food in the human digestive system.
Question 9
SLPaper 1A
Which process describes starch metabolism in humans?
Question 10
SLPaper 1A
A fluid sample is taken from the digestive tract of a mammal. The sample is basic (alkaline) and able to digest starch and proteins. From which part of the digestive tract was the fluid taken?