homeostasis

Question 1

explain the second messenger model as a way if controlling blood glucose levels?

Answer 1

• adrenaline binds to a transmembrane protein receptor on the cell surface membrane of a liver cell
• causes protein to change shape on inside of membrane
• change of shape causes adenyl cyclase to be activated
• which converts ATP to cyclic AMP
• the cAMP (second messenger) binds to protein kinase enzyme, changing its shale and activating it
• catalyses the conversion of glycogen to glucose

Question 2

what are the three sources of blood glucose?

Answer 2

• diet
• hydrolysis of glycogen
• production of glucose from non-carbohydrates (gluconeogenesis)

Question 3

which cell secretes insulin?

Answer 3

• beta cells on the islets of Langerhans in the pancreas

Question 4

what cells secrete glucagon?

Answer 4

• alpha cells on the islets of Langerhans in the pancreas

Question 5

describe the process of glycogenesis

Answer 5

• blood concentration increases and insulin released
• insulin binds to a receptor on a target cell
• this changes the tertiary structure of glucose transport proteins
• glucose diffuses into the cell
• more glucose carrier/transport proteins are formed from the fusion of protein carrying vesicles with the cell surface membrane
• this activates enzymes which convert glucose into glycogen or fats

Question 6

in what ways does the secretion of insulin cause the blood glucose concentration to decrease?

Answer 6

• increases cell permeability to glucose
• more glucose into cells
• more conversion of glucose to glycogen or fats
• increases rate of respiration

Question 7

what is type one diabetes?

Answer 7

• insulin dependent
• body unable to produce insulin
• normally starts in childhood

Question 8

what is type 2 diabetes?

Answer 8

• insulin independent
• glycoprotein receptors being lost or losing receptiveness
• usually in people over 40
• symptoms less severe
• develops slowly

Question 9

how can type one diabetes be controlled?

Answer 9

• insulin injections
• cannot be taken orally as insulin may he digested as it is a protein
• injected 2-4 times a day

Question 10

how is type 2 diabetes controlled?

Answer 10

• exercise and diet