Homeostasis basics Flashcards
What is homeostasis?
The maintenance of a stable internal environment
What does homeostasis keep constant?
Internal environment
State of dynamic equilibrium
Why is it important to maintain the right core body temperature and blood pH?
They affect enzymes and enzyme activity controls the rate of metabolic reactions
Why is it important to maintain the right blood glucose concentration?
Cells need glucose for energy and blood glucose concentration affects the water potential of blood
What happens to the rate of metabolic reactions as the temperature increases? Why?
Increases
There will be more kinetic energy so molecules move faster. Making the substrate molecules more likely to collide with the enzyme’s active site, each collision is also more likely to result in a reaction
What happens to the enzymes if the temperature is too high?
The enzymes have more energy and vibrate so much that the hydrogen bonds in the 3D structure causing the active site to be changed and the enzyme is denatured
Can’t catalyse the reactions anymore
What happens to the enzyme activity if the temperature is too low?
The enzyme activity is reduced, slowing the rate of metabolic reactions
How does blood pH affect enzymes?
If it is too high or too low the enzymes will become denatured
Why do enzymes become denatured in highly acidic or alkaline conditions?
The ionic bonds and hydrogen bonds that hold them in their 3D shape are broken, the shape of the enzymes active site is changed and it can’t work as a catalyst
What is optimum pH for enzymes?
Usually around pH7
What is the equation to calculate pH?
pH = -log10 [H+]
What happens when the blood glucose concentration is too high?
The water potential of blood is reduced to a point where water molecules diffuse out of cells into the blood by osmosis - cells shrivel and die
What happens when the blood glucose concentration is too low?
Cells are unable to carry out normal activities because there isn’t enough glucose for respiration to provide energy
What do receptors in the homeostatic system do?
They detect when a level is too high or too low and the information’s communicated via the nervous system or the hormonal system to effectors
What is negative feedback?
The mechanism that restores the level to normal
