Diabetes (Advanced Level)
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Islets of Langerhans
The pancreas has two functions: to make hormones (endocrine) and to produce enzymes for digestion (exocrine).
The islets of Langerhans make the hormones insulin and glucagon. The alpha cells (stained red) make the glucagon and the beta cells (green) produce insulin. Nuclei are stained blue.
The islets make up only just over 2% of the pancreatic tissue
Alpha and beta cells in the islets of Langerhans. Source: Masur
Specialised cells
Beta cells are specialised to produce insulin. They have a well-developed rough endoplasmic reticulum , to produce the protein hormone. This is then stored in cytoplasmic vesicles before it is secreted. The process requires energy and beta cells contain many mitochondria to provide ATP.
Roll over the image to see the parts of the cell involved in insulin production.
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Protein synthesis
Insulin is a protein and there are several stages in its production. The animation shows the process of protein synthesis. When insulin is being produced, it is the insulin gene in the nucleus that is transcribed into messenger RNA .
Protein synthesis
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Question 5
a)
Which cells produce insulin?
b)
What is the role of the ribosomes in the rough endoplasmic
reticulum in the production of insulin?
c)
What is the role of the Golgi apparatus in the production of
insulin?
b)
What is the role of the DNA in the production of insulin?
Acarbose
This type 2 diabetes medication is not much used now.
Amino acids
The basic building blocks of proteins. There are twenty amino acids
used, in different combinations, to make every protein required by
the human body.
ATP (adenosine triphosphate)
A small organic non-protein molecule that is a source of chemical
energy within a cell.
Autoimmune disease
A disorder where the body's immune system behaves abnormally and
starts attacking its own cells
Autopsies
The study of the human body to investigate how a disease or injury
leads to death
Cardiovascular disorders
Diseases linked to the heart and its blood vessels, for example heart
disease and stroke
Diabetic ketoacidosis (DKA)
When glucose is high in the blood but unable to enter cells, the body
starts using stores of fat for energy, which results in the
production of acidic ketones as a by-product. If ketone levels rise
unchecked a hyperglycaemic coma can result which may be fatal.
Disulfide bridge
A covalent S-S bond that joins two cysteine amino acids together,
also called an SS-bond or disulfide bond.
Duodenum
Within the human body this is the first 25 - 30cm long section of the
small intestine.
Embryo
The name for a group of cells that are developing into a foetus. In
humans this is from implantation to the 8th week of development
Endocrine gland
A gland which secretes hormones straight into the bloodstream rather
into the blood via a tube or duct.
Enzyme
Biological catalysts that speed up chemical reactions.
Exocrine cells
Cells found in the exocrine glands that secrete hormones into ducts,
as opposed to straight into the bloodstream.
Fermentation
Process where microorganisms are cultured so that they reproduce and
increase in quantity
Fatty acid
Large molecule consisting of a carboxylic acid (RCOOH) with the 'R'
being a long unbranched hydrocarbon chain.
Gastrointestinal
Relating to the body's digestive system, including the stomach and
intestines.
Gene
A short piece of DNA which is responsible for the inheritance of a
particular characteristic. It codes for the production of a specific
protein
Gene therapy
A new, experimental method of fighting disease by replacing a
defective gene with a healthy gene
Genetic engineering
A general name for the processes which scientists use to produce
desired characteristics or substances that are in short supply, such
as human insulin
Glucagon
A hormone produced by the pancreas. It causes the liver to convert
glycogen back to glucose and to release glucose into the bloodstream.
Glucose
A type of sugar: a monosaccharide with 6 carbon atoms (a hexose
sugar)
Glycogen
A polysaccharide,
(C 6 H 10 O 5 ) n , that is stored in the liver and in muscles and can be converted back into glucose when needed by the body.
(C 6 H 10 O 5 ) n , that is stored in the liver and in muscles and can be converted back into glucose when needed by the body.
Harvested
The process by which a useful substance is extracted
Home Office
The UK government department responsible for regulating the use of
animals in scientific research
Hormone
A chemical messenger produced by a particular gland or cells of the
endocrine system. Hormones are transported throughout the body in the
blood stream but they produce a response only in specific target
cells
Hydrogen bond
An intermolecular force between hydrogen, when it is covalently
bonded to a highly electronegative atom (fluorine, oxygen or
nitrogen), and an oxygen, nitrogen or fluorine atom on another
molecule.
Hyperglycaemic
This is the term used when the blood glucose level is too high (more
than 10 mmol/l)
Hypoglycaemic
This is the term used when the blood glucose level is too low (less
than 4 mmol/l)
Immune system
The body's own system for protecting it against disease (where it
produces antibodies to attack invading pathogens)
In vitro fertilisation
A process where the egg is fertilised outside of the body and then
transferred back into the uterus to develop normally
Insulin
A hormone produced by the pancreas. It is active in controlling blood
glucose levels as it allows cells in the body to take in and store
glucose.
Liver
A large organ in the upper abdomen which manufactures, stores and
breaks down substances as required by the body
Mitochondria
Organelles within cells that produce ATP, used as a store of chemical
energy. Often called the cell's powerhouse.
Mucosa
The membrane that lines the body's cavities and passages. In certain
areas, such as the nose and mouth, this membrane absorbs substances
and secretes mucus.
Non-animal alternatives
Processes such as cell culture, computer modelling, imaging and
microdosing of human volunteers that can give information on
potential harmful effects of a substance
Obesity
A disorder where an excessive amount of fat has accumulated in the
body. It results when the energy taken in as food is stored in the
body instead of being used up through activity
Organelles
A distinct part of the cell, such as the nucleus, ribosome or
mitochondrion, which has structure and function.
Pancreas
An endocrine gland which produces insulin
Polysaccharides
Complex carbohydrates consisting of more than one sugar molecule.
Proteins
A polymer made up of amino acids joined by peptide bonds. The amino
acids present and the order in which they occur vary from one protein
to another.
Receptors
Protein molecules attached to cells that only bind to specific
molecules with a particular structure.
Respiration
The biochemical process by which the cells in the body release energy
Messenger RNA (ribonucleic acid)
Single chains of nucleotide units that transmit the information from
the DNA inside the cell's nucleus to the ribosomes in the cytoplasm
which synthesise the required proteins.
Ribosome
Small organelles that synthesise proteins.
Rough endoplasmic reticulum
A network of membranes within a cell which has ribosomes attached to
it. They are important in the synthesis and transportation of
proteins.
Stem cells
Undifferentiated cells that can develop into a diverse range of
specialised cell types.
Sterile
Uncontaminated by microorganisms
Triglycerides
The most common lipid found in nature and consists of a single
glycerol molecule bonded to three fatty acids.
UK Law [for animal testing]
Animal welfare is regulated in the UK by the Animal (Scientific
Procedures) Act 1986
Vesicle
A small sac that stores or transports substances inside a cell.
X-ray crystallography
A technique that uses the diffraction of X-rays to determine the
molecular structure of a crystalline substance.
