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B io Factsheet
www.curriculum-press.co.uk Number 157
Diabetes - Management or Cure?
This Factsheet: 1. Managing diabetes
· Summarises how glucose concentration are maintained within Diabetics need to know the concentration of glucose in their blood.
narrow limits in the body. This has been made much easier by the introduction of reliable,
· Outlines the causes of diabetes. accurate, and "user-friendly" self-glucose monitoring devices.
· Summarises how diabetes is being managed and the latest
research to find a cure. Designs that utilize an enzyme electrode (such as glucose oxidase)
· Describes the type of exam questions that have been set recently and either a hydrogen peroxide or an oxygen detection system
on this topic. appear to be the most successful to date. These electrodes can be
placed subcutaneously or intravenously.
Normally, the level of glucose in the blood is controlled by negative
feedback (Fig 1). One new sensor uses polymer spheres within a hydrogel that swells
If blood glucose concentration increases, insulin is released from the and shrinks reversibly and changes colour in the presence of
pancreas and this targets the liver and muscles so that glucose levels glucose. The hydrogel contains a glucose-recognition group.
fall again. If blood glucose concentration falls then the pancreas
releases glucagon and this leads to glucose levels rising again. As glucose binds to this group the hydrogel expands causing an
increase in the spacing between the spheres. This causes a shift in
Diabetes is a condition in which the concentration of glucose in the the diffracted light to longer wavelengths which can be converted
blood increases because the body cannot control it properly. There to an electrical signal.
are two types:
Type 1: the body cannot make insulin. This is because cells of the This can be calibrated to provide a glucose reading.
body's immune system release agents including cytokines
which kill insulin-producing -cells. The insulin then has
to be injected. Exam Hint: Refer to blood glucose concentration rather than to
Type 2: the body cannot make enough insulin or the insulin it blood glucose level. The blood volume is constantly changing
produces does not work properly because other hormones but for osmotic reasons blood concentration must be controlled.
interfere with its actions.
Fig 1. Glucose negative feedback control
Blood Glucose concentration rises. Insulin stimulates the conversion of glucose to
Sensed by receptors on cells. glycogen which is stored in the liver and muscle so
cells secrete insulin. blood glucose concentration falls.
Islets of Langerhans made Insulin cells no longer
of and cells stimulated
Glucogon stimulates the release of glucose from
Pancreas glycogen so blood glucose concentration falls.
Glucagon cells no longer
Blood Glucose concentration falls
Sensed by receptors on the cells
cells secrete glucagon
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Diabetes - Management or Cure? Bio Factsheet
Curing diabetes Exam Questions
Recently, scientists have announced that there may soon be a cure for Glucose regulation is on every A level specification. Because it involves pulling
Type 1 diabetes. Several different techniques have shown promise: together several areas of Biology cells, enzymes, hormones, metabolism,
homeostasis, disease and technology, it is a perfect synoptic topic.
Firstly, mice were treated with a chemical to induce Type-1 diabetes.…read more