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Year 11
OCR
Foundation

The importance of maintaining constant conditions in the body, including osmosis

I can explain why it is important for living organisms to maintain a constant internal environment.

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New
New
Year 11
OCR
Foundation

The importance of maintaining constant conditions in the body, including osmosis

I can explain why it is important for living organisms to maintain a constant internal environment.

Download all resources
Share activities with pupils

Lesson details

Key learning points

  1. If conditions in the body change too much, this can be dangerous to our health.
  2. Changes in body temperature affect the rate of chemical reactions and can impact enzyme activity.
  3. Extreme changes in body temperature can lead to hypothermia or hyperthermia and death.
  4. Changes in water content of the fluid around cells can lead to cells shrinking or bursting due to osmosis.
  5. Use of antagonistic effects to maintain a constant environment.

Common misconception

It is common for pupils to misunderstand the links between increased or decreased body temperature and the impact on enzyme function, and changes in water concentration and cell structure.

Explanations of the effect of temperature on enzyme activity, the link between body temperature and enzyme function, and conditions such as hyper- and hypo-thermia are made. The link between water balance, osmosis and cell shapes are also explored.

Keywords

  • Enzyme - a protein which acts as a biological catalyst

  • Internal body temperature - the optimal internal temperature of our body, which is about 37°C

  • Homeostasis - the regulation of the internal conditions to maintain optimum conditions for enzyme action and all cell functions

  • Osmosis - the net movement of water molecules through a selectively-permeable membrane from high to low concentration of water molecules

  • Antagonistic - effectors and effects that work against each other

Use a Bunsen burner and beaker of water to explore the process of body temperature homeostasis practically. It's quick to set up but can be a real challenge to complete, and should encourage students to really think about how they are responding to the observed changing conditions in the beaker.
Teacher tip

Equipment

Optional: Bunsen burner, tripod, gauze, heat proof mat, thermometer, beaker, ice cubes.

Licence

This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).

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Starter quiz

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6 Questions

Q1.
Below is a simplified diagram of an enzyme. What is shown by A?
An image in a quiz
Correct Answer: Active site, An active site, the active site
Q2.
Which of the following are effectors?
Correct answer: glands
the brain
Correct answer: muscles
the spinal cord
motor neurone
Q3.
True or false? Enzymes are catalysts.
Correct answer: true
false
Q4.
The graph shows the rate of an enzyme controlled reaction. Point A represents the temperature for the enzyme.
An image in a quiz
Correct Answer: optimum, optimal
Q5.
The graph shows the rate of an enzyme controlled reaction. Why is the rate of reaction decreasing at point c?
An image in a quiz
The enzyme is being killed.
The enzyme is too hot.
The enzyme has run out of active sites.
Correct answer: The enzyme is becoming denatured.
The enzyme has run out of substrate.
Q6.
If a significant increase in body temperature is sustained, it can lead to ...
hypeothermia
Correct answer: hyperthermia

Exit quiz

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6 Questions

Q1.
The maintenance of a constant internal environment is known as...
Correct Answer: homeostasis
Q2.
What name is given to enzymes whose active site has changed shape and no longer fits to its substrate?
Correct Answer: denatured
Q3.
Water moves in and out of cells by ...
Correct Answer: osmosis, osmosis.
Q4.
Order the statements below to describe how the body responds to an increase in body temperature.
1 - A temperature receptor detects an increase in temperature.
2 - A signal is sent to the coordination centre e.g. brain.
3 - The coordination centre sends a message to the sweat glands.
4 - Sweat glands increase sweat production.
5 - Sweat evaporates.
6 - The body cools down.
Q5.
Match the water level to the effect on cells.
Correct Answer:Too little water outside the cell,water will leave cells by osmosis and they will shrivel.

water will leave cells by osmosis and they will shrivel.

Correct Answer:Too much water inside the cell,water will enter cells and they will swell and may burst.

water will enter cells and they will swell and may burst.

Q6.
Which of the following are antagonistic effects?
Correct answer: insulin which decreases blood sugar, and glucagon which increases blood sugar
thyroid stimulating hormone which increases the production of thyroxine
Correct answer: sweating to cool the body down, and shivering to warm the body up
the brain sending signals down a relay neurone to a motor neurone