1 - Basics Flashcards
What is homeostasis?
The maintenance of a stable internal environment
Which three things is it important to keep constant during homeostasis?
Temperature
PH
Blood Glucose Concentration
What happens when your body temperature gets too high (e.g.. over 40 degrees)?
The metabolic reactions taking place will stop as the enzymes molecules will vibrate more meaning the vibrations will break the hydrogen bonds that hold the enzymes 3D shape, therefore the active site will change shape and so the sublate will no longer fit the enzyme and so the enzyme is denatured.
What happens when your body temperature gets too low?
The rate of metabolic reactions taking place will slow down
What is the optimum temperature for enzyme activity to take place at?
37 degrees
Why is homeostasis important?
It is important as temperature and PH affect the rate of metabolic reactions, and blood glucose concentration should be kept regular as cells need glucose for energy and it affects water potential levels
What happens if PH levels are too high or low? why?
Enzymes will become denatured as the ionic and hydrogen bonds holding the enzymes 3D shape will be broken and so the specific shape of the active site will change and so the substrate will no longer fit
What is the optimum PH level?
PH7 - neutral
How is PH calculated?
It is calculated based on the concentration of hydrogen ions in the environment
The greater the concentration of H+ in the environment the the lower the PH
What is the equation for working out PH?
PH = log10 [H+]
What is the logarithmic scale?
A scale that uses a logarithm of a number instead of the number itself each value using Log10 is 10 times larger than the value before
What happens if the blood glucose concentration is too high?
The water potential of blood is reduced to a point where water molecules diffuse out of the cells into the blood by osmosis, which can cause the cells to shrivel up and die
What happens if the blood glucose concentration is too low?
Cells are unable to carry out normal activities as there is not enough glucose for respiration to provide energy
What is a negative feedback mechanism?
A mechanism that restores a level back to normal in a system
Describe a negative feedback loop
Normal level > Level changes from normal > Receptors detect change > Communication via nervous or hormonal system > Effectors respond > Loops back to Normal level
Why does homeostasis involve multiple negative feedback loops?
Because it allows for more control over changes in your internal environment rather than just having one. It means you can actively change a level so it returns to normal again.
What would happen if you only have one negative feedback mechanism?
You would only be able to change a level in one direction so it returns to normal. There would be a slower response and less control
What is a positive feedback mechanism?
A mechanism that amplifies a change away from a normal level in a system
Describe a positive feedback mechanism?
Normal level > Normal level changes > Receptors detect change > Communication via nervous or hormonal system > effectors respond > (Back to normal level) (change amplified)
Why isn’t positive feedback used in homeostasis?
Because it doesn’t keep your internal environment stable
What is positive feedback used for?
It is used to rapidly activate processes in the body and can also happen when a homeostatic system breaks down
