Blood Glucose control and diabetes

Question 1

Describe the mode of action of hormones

Answer 1

Hormones are produced in endocrine glands and are secreted
into the blood. They are carried in the blood plasma to all
cells. They only act on target cells due to specific receptors on
their cell surface membrane.
They are effective at low concentrations and can have
widespread and long lasting effect

Question 2

Explain why glucose control is negative feedback

Answer 2

Blood glucose increase triggers a response which reduces the effect
of a change; Once the effect has reached normal the response will
be switched of

Question 3

Explain why it is important that the blood glucose level is maintained

Answer 3

If blood glucose levels fall, there will not be enough for
respiration in the brain cells. If blood glucose gets too
high, it will lower the water potential too far, and water
will move out of cells causing damage

Question 4

Explain what happens when blood glucose concentration increases

Answer 4

Beta cells in the islets of Langerhans detect the change and release
insulin into the blood. Insulin travels round the blood and attaches
to receptors on target cells (liver and muscles)

Question 5

Describe the role of insulin in blood glucose control

Answer 5

Insulin activates enzymes that increases the number of
protein carriers in the membrane, increasing the uptake
of glucose. It activates glycogenesis (converting glucose
to glycogen) and changes glucose to lipids

Question 6

Describe the role of glucagon in blood glucose control

Answer 6

Glucagon activates enzymes that cause glycogenolysis
(hydrolysis of glycogen to glucose) and gluconeogenesis
(change of amino acids and glycerol to glucose)

Question 7

Describe glycogenesis

Answer 7

The conversion of glucose into glycogen using a
condensation reaction to form a glycosidic bond.

Question 8

Describe glycogenolysis

Answer 8

The hydrolysis of glycogen into glucose

Question 9

Describe gluconeogenesis

Answer 9

Changing amino acids and glycerol to glucose

Question 10

Describe how the liver is involved in the regulation of blood glucose

Answer 10

The liver cells are the target cells of insulin and glucagon.
The hormones bind to receptors on the liver cell surface
membranes. The liver cells takes in glucose when blood
glucose is high, and changes glucose into glycogen for
storage. The lover cells can hydrolyse glycogen to
glucose to increase blood glucose concentration.
The permeability of liver cells for glucose can be changed
by insulin

Question 11

Describe how the pancreas is involved in
the regulation of blood glucose

Answer 11

The beta cells in the islets of Langerhans detect a rise in blood
glucose and secrete insulin directly into the blood plasma.
The alpha cells detect a fall in the blood glucose and secrete
glucagon directly into the blood plasma

Question 12

What is the cause of type 1 diabetes

Answer 12

Autoimmune
More likely to develop in childhood
beta cells in islets of Langerhans destroyed
pancreas is unable to produce insulin
evidence that there is genetic predisposition environmental
triggers such as viral infection may cause mutations that lead to type 1 diabetes

Question 13

what’s the type of type 2 diabetes

Answer 13

Metabolic
associated with lifestyle, more likely to develop later in life
linked to obesity, poor diet, sedentary lifestyle
lower amounts of insulin produced
cells may be insulin resistant and not respond to insulin
released
evidence for genetic predisposition
some links to medication