Primary 5 · Science · Systems: Digestive
Systems: Digestive questions for Primary 5 Science
10 questions to work through online, 2 of them written out the way the paper asks. Answer and you get the working straight away, then a score at the end. No sign-up, and you can retake it as often as you like.
- Reading an experiment
- Where absorption happens
- What a digestive juice does
- Reasoning about temperature
- What the large intestine does
- Reasoning about a missing part
- Why the surface matters
- Naming the control
- Naming a part
- Applying the ideas
| Tube | Food | Digestive juice added | Food broken down after 1 hour |
|---|---|---|---|
| A | ✓ | ✓ | ✓ |
| B | ✓ | ✗ | ✗ |
| Tube | Temperature (°C) | Time to break the food down (min) |
|---|---|---|
| P | 10 | over 60 |
| Q | 37 | 18 |
| R | 80 | no change |
Answers and explanations for all 10 questions
Every answer with the reasoning behind it. Worth reading after you have tried the set — or on its own, if you are a parent marking it.
In the experiment shown above, what is the purpose of tube B?
Answer: to show that the food does not break down on its own
B is the control. Without it, someone could argue the food would have broken down anyway. B has everything except the juice and nothing happens, so the juice must be the cause.
At which part of the diagram above is most digested food absorbed into the blood?
Answer: Y
Y is the small intestine, whose length and folds give the enormous surface that absorption needs.
Which two of these are true of digestive juices?
Answer: A and B only
Digestive juices break food into pieces small enough to pass into the blood, and they work fastest at the temperature the body actually keeps.
Based on the table above, which statement is correct?
Answer: The juice works best at about body temperature and is destroyed by high heat.
18 minutes at 37 °C, over an hour at 10 °C, and nothing at 80 °C. Cold slows the juice down; strong heat stops it working altogether.
What mainly happens at the part labelled Z in the diagram?
Answer: Water is absorbed from what is left.
By the large intestine the useful food has already gone into the blood. What remains has its water taken out before it leaves the body.
A person has had their large intestine removed. Which two effects would you expect?
Answer: A and B only
The large intestine's job is absorbing water, so losing it means more water is lost. Digestion and the absorption of food both happen earlier and carry on as before.
The inside of the small intestine is covered in millions of tiny finger-like folds. What difference do they make?
Answer: They greatly increase the surface across which food can be absorbed.
Absorption happens across a surface, so the more surface there is, the more food gets into the blood. The folds turn a tube into an enormous absorbing area.
In an experiment, one tube is set up with everything except the substance being tested, so that the others can be compared against it. What is that tube called? The ______ .
Answer: control
The set-up with everything except the thing being tested is the control.
Look at the part labelled X in the diagram above, where food is churned with digestive juices. What is the name of this part?
Answer: stomach
X is the stomach, where food is churned with digestive juices.
Why is it sensible to chew food thoroughly rather than swallowing it in large lumps?
Answer: Smaller pieces give the digestive juices more surface to work on.
Digestive juices act on the surface of the food. Chewing multiplies that surface, so digestion is faster and more complete.