Hormones glucagon and insulin are produced in the alpha and beta cells respectively in the Islet of Langerhan in the pancreas. They are involved in the negative feedback system of blood glucose regulation in homeostasis.
GLUCAGON: when there is a low blood glucose concentration, the pancreas detect this and alpha cells produce and release glucagon. Glucagon causes the cells of the body to absorb less glucose from the blood. It also inhibits the process of converting glucose into glycogen (glycogenesis) and cause gluconeogenesis (process of converting amino acids/proteins and lipids/fats into glucose) and glycogenolysis (conversion of glycogen to glucose). Finally, glucagon decreases the rate of respiration so less glucose is required.
INSULIN: when blood glucose is high, insulin is released. Insulin binds with cell surface receptors of cells and activates the enzymes attached to the receptor. The enzymes cause a conformational change in the structural proteins that surround glucose transport protein containing vesicles, causing them to move out of the way so the vesicles migrate up to the cell membrane and glucose transport proteins can fuse with it. Thus, more glucose can be taken in by cells. Insulin also cause glycogenesis (converting glucose into glycogen) and inhibits gluconeogenesis and glycogenolysis.
Basically insulin decreases blood glucose concentration (eg. after eating) and glucagon increases it (eg. skipping breakfast in the morning)
Two genes, BRCA1, located on chromosome 17q21 (5,6), and BRCA2, located on 13q12-13 (7–9), have been shown to predispose to familial breast cancer.
The answer to this question is :
D. Obstacle Evaluation
Answer: cofactors.
Explanation:
Epinephrine, insulin and auxins are cofactors.
Cofactors are non protein substance which activate enzymes activity by increasing the rate of chemical reaction of enzymes. They are organic molecules and they assist in enzyme activity. They exist in performing some reactions the enzymes cannot perform alone.
For example, insulin activate enzyme hexokinase which phosphorylate glucose.
