Homeostasis and Enzyme Activity
What is homeostasis in mammals?
The maintenance of a stable internal environment within restricted limits.
What is negative feedback in biological systems?
A mechanism that counteracts a change to bring a system back to its original state.
Name 3 processes that occur in the liver, to maintain glucose levels.
Glycogenesis, Glycogenolysis, Gluconeogenesis
Which 2 hormones regulate blood glucose, and where are they produced?
Insulin - Beta Cells
Glucagon - Alpha Cells
Which type of diabetes is insulin dependent?
Type 1
Why is maintaining a stable core temperature important for enzyme activity?
Enzymes have an optimal temperature range; deviations can reduce their efficiency or denature them.
How does negative feedback help restore systems to their original state?
By initiating processes that reverse the direction of change, maintaining homeostasis.
What is the role of the liver in glycogenesis?
Converts excess glucose to glycogen for storage.
What is the role of adrenaline in blood glucose regulation?
Prepares the body for 'fight or flight' by increasing blood glucose levels through glycogenolysis.
What is the relationship between diet and Type II diabetes, and how is it controlled?
Type II diabetes is often linked to obesity and poor diet; it can be managed through lifestyle changes, including a balanced diet and regular exercise.
How does maintaining a stable blood pH affect enzyme activity?
Enzymes function best within a specific pH range; deviations can alter their shape and reduce activity.
Why are separate mechanisms needed to control blood glucose in different directions?
To provide precise regulation
What is the term for the breakdown of glycogen into glucose, to increase blood glucose levels.
Glycogenolysis
How does insulin help control the uptake of glucose by target cells?
- By binding to insulin receptors on cell surface membranes.
-This causes a change in shape of the glucose transport carriers, allowing them to open up
-Also causes an increase in the number of glucose carrier proteins.
Why is the action of adrenaline called the second messenger model?
Adrenaline cannot enter the cell; it is the first messenger and activates a second messenger in the target cell
Why is it important to maintain stable blood glucose concentration?
Acts as a respiratory substrate to ensure a constant supply of energy for cells and maintains blood osmotic pressure.
Provide an example of negative feedback in a biological system.
Insulin release in response to high blood glucose levels.
What is gluconeogenesis, and where does it occur?
Synthesis of glucose from non-carbohydrate sources, primarily in the liver.
How does insulin activate the conversion of glucose to glycogen?
Through activation of the enzyme glycogen synthase, promoting glycogenesis
What role does adenylate cyclase play in the second messenger model?
Converts ATP to cAMP, which acts as a second messenger
How does blood glucose concentration affect the water potential of blood?
High glucose levels decrease water potential, leading to water movement into blood vessels.
Provide an example of positive feedback in a biological system.
Oxytocin release during childbirth to intensify contractions.
How does the liver contribute to maintaining blood glucose levels during fasting?
By performing glycogenolysis and gluconeogenesis to release glucose into the bloodstream.
What is the role of glucagon in regulating blood glucose?
Stimulates glycogenolysis and gluconeogenesis to increase blood glucose levels.
How does cyclic AMP (cAMP) function in the second messenger model?
Acts as a secondary messenger that activates protein kinase, to convert glycogen to glucose