16.1 principals of homeostasis

Question 1

What is homeostasis

Answer 1

The maintenance of an internal environment within restricted limits of organisms

It ensures that all cells in the body are in an environment that meets their requirements and allows them to function normally despite environmental changes

Question 2

What are some examples for changes in internal and external conditions

Answer 2

PH
Temperature
Water potential

These changes however occur at an optimum point

Question 3

Why is homeostasis important for enzymes

Answer 3

Enzymes control biochemical reactions within cells, and channel proteins.
These are sensitive to changes in PH and temperature

Any change to these conditions reduces rate of reaction for these enzymes and may even denature them. So overall it is important to maintain these conditions so biochemical reactions can keep occurring at a suitable rate

Question 4

Why is homeostasis important for maintaining water potential in the blood

Answer 4

• Changes to water potential of blood and tissue fluids may cause cells to shrink or expand
• They may even burst if loads of water enters by osmosis or loads leaves which makes them shrivel up

Maintenance of constant blood glucose concentration is essential in ensuring a constant water potential. It is also essential in ensuring a reliable source of glucose for respiration in cells

Question 5

Why is it good for organisms to have homeostasis working

Answer 5

They can adapt to different environmental conditions as there are different external environments.

These organisms have a wider geographical range so they have a greater chance of finding food, mating, shelter

Question 6

The optimum point is where a system operates best.
This is maintained by…

Answer 6

• Receptor: Detects any deviation from an optimum point
  This informs the coordination centre
• Coordination centre coordinates information from receptors and sends instructions to the appropriate…
• Effector is often a muscle or gland which brings about the changes needed to return system to an optimum point

Question 7

What is a feedback mechanism

Answer 7

Where receptor responds to stimulus created by the change to the system brought about by the effector

Question 8

What is negative feedback

Answer 8

The change produced by the control system leads to a change in the stimulus detected by the receptor and turns the system off

Question 9

What is positive feedback

Answer 9

Occurs when deviation from an optimum causes changes that result in an even greater deviation from the normal