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Unit F222: Growth, Development and Disease
Module 1: The Developing Cell
2
...
1 Mitosis as Part of the Cell Cycle


The cell cycle : Mitosis is the dramatic part of cell division, yet accounts for only a
small proportion of the cell cycle
...
Studying stem cells and their differentiation has opened
up new possibilities for the treatment of disease



Uncontrolled cell division can result in the formation of tumours
...


You will be expected to be able to:
(a) describe the cell cycle, with reference to interphase (G1,S and G2), mitosis and
cytokinesis leading to diploid cells;
The cell cycle is divided into a dividing (mitosis) and non-dividing stages (interphase made up of G1, S and G2)
...

A nucleotide contains a pentose sugar, a phosphate group and a nitrogen containing base (nitrogenous base)
...


Draw it here!

The pentose sugar in DNA is deoxy-ribose and in RNA is ribose
...
g
...
g
...

Nucleotides are joined by the phosphate group of one nucleotide joining to the ribose group of the next nucleotide
(phospho-diester bond), forming a sugar-phosphate backbone
...

In DNA, two polynucleotide strands are joined by specific complementary base pairing brought about by hydrogen
bonding
...


The two strands of DNA are anti-parallel i
...
the two polynucleotides run in opposite directions
...
g
...


(c) explain how DNA replicates semi-conservatively during the S phase of the cell
cycle








During the S phase (interphase) the DNA is replicated (semi-conservative)
...

the DNA helix unwinds and unzips (by an enzyme – helicase)
hydrogen bonds between the bases are broken
free nucleotides in the nucleus are activated (have two phosphates added to them)
each strand acts as a template, and bases of the activated nucleotides pair up with their complementary base on
each of the original strands
the two phosphates are removed from the activated nucleotide – this provides energy for linking the growing strands
of nucleotides together
this process is controlled by an enzyme DNA polymerase
A new DNA molecule is composed of one newly made DNA strand and the other strand is conserved from the old DNA
molecule
...
It forms phospho-diester bonds between
polynucleotide fragments
...


Colour this
in!

15

Meselsohn and Stahl labelled DNA (from bacteria) with ‗heavy‘ nitrogen ( N)
...
They found (by differential centrifugation) that all the DNA
formed was half way in density between the heavy and the light DNA
...


first generation

second generation

third generation

all heavy (15N) DNA

all hybrid DNA

half light 14N DNA;

(d) outline the processes taking placeN / the G1 and G2 points in the cycle;N DNA
(14 at 15N)
half hybrid 14N/15
During the G1 phase (interphase) new organelles are synthesised and protein is synthesised
...

During the G2 phase (interphase) further synthesis of organelles occurs and the spindle apparatus is assembled

(e) describe the appearance of the components of the nucleus and cell during
mitosis with reference to: nuclear envelope, centrioles, spindle fibres, centromere,
chromatids and chromosomes;
During mitosis a parent nucleus divides to produce 2 new daughter nuclei, each containing an exact copy of the DNA of the
parent nucleus
...

Increasing cell number in this way occurs for growth and tissue repair and in asexual reproduction
...

The DNA molecules replicate in the S phase, making an exact copy of the bases on each chromatid, so the chromatids are
identical
...
This way mitosis produces two genetically
identical cells
...


A chromosome is composed of DNA wrapped around histone proteins
...
After replication of the chromosome, it consists of two chromatids, each identical to the original
chromosome, joined at the centromere
...

During prophase the nuclear membrane breaks down and the chromosomes become more compact by coiling up
...
By the end of prophase, the
spindle has formed
...
The spindle fibres attach to a special area on
the chromosome called the centromere (the protein structure it attaches to is called the kinetochore)
...

At telophase the chromatids arrive at the poles of the cell and start to uncoil and the nuclear membrane re-forms
...

Interphase is the period between divisions, when cell organelles and DNA are replicated
...

Chromosomes

are

Cell

envelope

Chromosomes

Stage of division

membrane

Intact
...


nucleus
...


Prophase

Separate

Coil & condense
...


vesicles
...


Breaks

into smaller

opposite poles of the cell
...


Absent
...


At opposite poles of the cell
...


Present
...


Reforms
...


the equator of the cell
...


Telophase

Reach the poles of the
cell

–

now

chromosomes
...


of

By the end of cytokinesis,

chromosomes is present

each new cell will have one

and the cell

at each end of the cell
...


divides into

Intact
...


each new cell will have a
full set of chromosomes
...


Interphase (G1)

Chromosomes

are

of centrioles
...


Present
...
A special phospholipid, which is normally hidden in the plasma membrane becomes
exposed on the surface and attracts macrophages that engulf the cell fragments
...


(f) state that cell deletion by apoptosis and cell addition by mitosis are essential
for normal growth and repair;
Apoptosis is required during embryonic development to prune away unwanted tissue e
...
a tadpole‘s tail
when it becomes a frog or to form separate fingers and toes in human embryos
...

Damage to the cell‘s DNA may trigger increased production of p53 protein which induces apoptosis, killing
potentially cancerous cells
...


(g) explain that damage to the p53 gene by agents such as UV radiation and
chemicals in tobacco smoke can lead to DNA damage going undetected and
leading to mutations;
The p53 protein is coded for by the p53 gene so if the gene is damaged, less p53 is synthesised and the
faulty cells are not destroyed
...


(h) explain that cancer is the result of uncontrolled cell division;








cells only divide a finite number of times before they undergo programmed cell death (apoptosis)
...


a mass of cells produced by uncontrolled mitosis is called a tumour
...
g
...

malignant – which spread throughout the body, via the blood and lymph, and invade other tissues to set up
secondary growths
...

a change in a gene or chromosome is called a mutation
...

an agent (something!) which causes mutations is called a mutagen
...

Be able to discuss the factors which increase mutation rates (and hence the likelihood of cancer):
ionising radiation
...
g
...

viruses (e
...
HPV, HTLV)
...

Be aware that:

1 in 3 people will develop cancer during their lifetime
...


55% of cancers are due to diet!

(j) describe the role of oncogenes and protooncogenes in uncontrolled cell
division;
A mutated gene which causes cancer is called an oncogene
...
The Ras proto-oncogene is
an example of a signal-transmitting molecule inside cells that can mutate into an oncogene
...
Many transcription factors are proto-oncogenes
...


(k) define the term stem cell;
Stem cells are primal undifferentiated cells which retain the ability to differentiate into other cell types
...

Stem cells have the potential to develop into many different cell types in the body
...
When a stem cell divides, each new cell has the potential to either remain a stem cell or
become another type of cell with a more specialized function, such as a muscle cell, a red blood cell, or a brain
cell
...


All blood cells
are derived from stem cells
(haemopoietic cells) in the bone
marrow
...


B-lymphocytes
and T-lymphocytes differ because
they mature in different parts of the
body
...
e
...


When a cell
differentiates, its size, shape,
polarity, metabolic activity and
responsiveness to signals may
change dramatically
...

With a few exceptions, cellular differentiation almost never involves a change in the DNA sequence
...
1
...

(a) you need to be able to outline the factors that may increase the risk of developing
cancers, with reference to
 types of radiation,
 carcinogens,
 ageing,
 viruses and heredity;
(b) evaluate the epidemiological evidence linking smoking with lung cancer; diet with bowel
cancer and mutations in the BRCA1 gene with breast cancer
...

 You need an awareness of how statistics are used to determine the significance of
results
...
e
...
There are more post-menopausal
women with breast cancer per 100,000 than the population as a whole
...

(c) outline the methods of detecting cancers of the breast and lungs, with reference to MRI,
X-rays, mammography, thermography, CT scans, ultrasound and PET scans;
 X-ray techniques used in mammography, CT scans and chest screening rely on the
greater density of tumour tissue compared with normal tissue
...
Expert analysis is necessary
...
Hot spots
show areas of high metabolic activity and so may indicate cancer
...

 PET (positron emission tomography) images biochemical activity and can detect
tumours and gauge their malignancy
...

 MRI (magnetic resonance imaging) uses a strong magnet and radio frequency
detection to detect the number and molecular environment of hydrogen atoms
...
An image in shades of grey is produced providing a
detailed image of the body organs without harmful X-rays or invasive surgery
...


• Treatment

and advice involves health professionals who inform and support both the
patient and their family throughout their treatment
...
This only
works for breast cells that are sensitive to oestrogen, so tests are made to check
which receptors are present before prescribing
...
This aims to
prevent metastasis
...

Palliative chemotherapy is given to control tumour growth where surgery is not
possible
...

 Immunotherapy The immune system is persuaded to attack tumour cells specifically
by locking on to specific antigens on the cell surface
...

 Complementary therapies are usually used alongside other treatments and include
acupuncture, dietary regimes, relaxation, meditation and herbalism
...

(f) describe how clinical trials may be used to establish the value of a cancer treatment,
with reference to the need for ‗blind‘ or ‗double blind‘ trials, randomisation and the use of
placebos (HSW6b, 7b);
 In a blind trial, the patients do not know if they are getting the therapeutic agent
or a placebo, but the researchers do
...

(g) discuss the social, ethical and economic consequences of both the development and
use of cancer treatments
...

(post-code lottery)
 Many treatments have significant side-effects (e
...
sterility or radiation damage)
...

 Living with cancer is socially and mentally debilitating for the patient and their
family and can cause great financial strain
...

Collection and presentation of qualitative (descriptive) data:
• Preparation of onion or garlic root tips to show the stages of mitosis;
• Observing, drawing and labelling of prepared slides showing the stages of mitosis;
• Extraction of DNA from plant material
...
2
...
Each gamete contains only one allele
of each gene
...


b) describe, with the aid of diagrams, the stages of meiosis: interphase, prophase 1, metaphase
1, anaphase 1, telophase 1, prophase 2, metaphase 2, anaphase 2, telophase 2 (no details of the
stage names within prophase 1 are required);

Meiosis animation

Compare meiosis and mitosis

Helpful
reminder

DNA is synthesised during Interphase (S phase)
...


Prophase I – chromosomes condense (become shorter and thicker), homologous chromosomes
pair up as bivalents, chiasmata may form
...
Spindle
fibres begin to form
...

Metaphase I – centrioles reach the poles of the cell, bivalents line up along the equator (middle)
of cell
...
Random alignment of homologous chromosomes either side of the
equator
...

Telophase I – chromosomes de-condense, nuclear envelopes reform around the two groups of
chromosomes
...


Prophase II – chromosomes condense, nuclear envelope begins to break down
...
Centrioles have migrated to opposite poles of the cell
...
Chromosomes line up on the equator of the cell
...

Telophase II – chromosomes de-condense, nuclear envelopes reform around the two groups of
chromosomes
...


(b) explain the importance of chiasma formation, crossing over, independent assortment of
chromosomes (metaphase 1) and chromatids (metaphase 2) resulting in genetic variation
between gametes and subsequently genetic variation between individuals;

In meiosis genetic variation is produced by:
1
...
g
...
During
metaphase 1, the chromosome No
...

Furthermore what chromosome 3 does in no way affects
how the maternal and paternal chromosome No
...

How one chromosome type lines up on the equator is
independent of how another chromosome type lines upINDEPENDENT ALIGNMENT

2
...
independent alignment of non-identical (because of crossing over) chromatids during
metaphase 2 of meiosis
Fertilisation produces further variation as genetically different gametes fuse randomly
...
These
different forms of a gene are called alleles
...
Antenatal
means ‘before birth’
...
This is known as preconceptual care
...
They involve the woman’s immunity to rubella
and making sure she has plenty of folic acid in her diet
...
It is not usually a dangerous disease for children or adults;
they suffer a raised temperature, tiredness and spots all over the
skin, but normally recover within ten days or so
...
If the mother has rubella, the virus
can cross the placenta and get into the foetus’ blood
...
Babies
which have been exposed to the rubella virus may be born with
heart and brain defects, deafness and perhaps cataracts
...
A simple blood test to check for antibodies
to rubella, will give the answer
...
If she is not, then she can have a rubella
vaccination
...

Folic acid

This is a B vitamin which is found in foods such as dark green vegetables, some breakfast
cereals, milk products, oranges and bananas
...
The neural tube is the part of the embryo which
develops into the spinal cord and brain
...
If the neural tube does not
develop properly, the baby may be born with spina bifida or other serious defects of the nervous
system
...

Taking folic acid pills each day before getting pregnant reduces the risk of having a baby with
spina bifida by about 70%
...
The midwife will find out if it is the mother’s first baby, if she or her
partner smoke
...

An assessment will be made of the probability of the baby being born with any kind of genetic disorder
...

Each time she attends the antenatal clinic, the mother will be weighed and her blood pressure will be measured
...
Her blood pressure may increase a little even in a healthy
pregnancy
...

The position of the baby in the uterus and the baby’s heart beat will be regularly checked
...

A urine sample will be collected to check for diabetes or kidney problems
...
She will be given a contact number to ring if she is
worried about anything
...

The programme provides many chances for the mother to get to know her midwife and develop a relationship
with her
...
These describe the required energy and nutrient
intakes of the British population
...
needs the same amount of each nutrient – they should show a normal
distribution
...

Initially the woman‘s fat stores are used to meet this demand for energy, so there is no
need to increase energy intake significantly until the last three months
...


Estimated Average Requirement (EAR):
This is an estimate of the average requirement of a population: 50% will need more than
the EAR for energy or nutrient, 50% will need less
...
Most people need more than
this
...

Despite their tremendous range of functions, proteins are made from the same amino
acids
...
Essential amino acids have to be
provided in the diet unlike non-essential amino acids which can be made in the liver from
other amino acids
...
Each
haem group contains an iron ion Fe²+ to which an oxygen molecule can bind
...




In epithelial cells, retinol is used to make retinoic acid, a chemical that aids cell
development and growth
...
This process allows the
eye to detect light at low intensity for example in late evening and at night
...
Vitamin C is also indirectly involved in the
transport of fatty acids into mitochondria for ATP production (aerobic respiration)
...
The skin of the mother’s abdomen is covered with a
slippery gel, which allows an ultrasound scanning probe to slid gently over its surface
...
The patterns of
these reflections are detected and converted in a picture on a screen
...
Later, crown-rump length and biparietal diameter may be measured
...
It gives a very accurate
estimation of the gestational age
...
The size of the head is related to brain
growth
...
Biparietal diameter is normally only measured after 12 weeks
...
fetalmeasurement
...

The NHS advises that pregnant women, and women who are trying to
conceive, should avoid drinking alcohol and should not get drunk
...
Apart from low birth weight, other symptoms of this
syndrome include poor muscle tone, abnormal limbs and heart defects,
increased risk of the child having cleft palate
...


Smoking

There are many different harmful chemicals in tobacco smoke
...

Haemoglobin combines with carbon monoxide and then cannot bind with
oxygen
...

Nicotine reduces the diameter of the foetus’ blood vessels
...
This, too, reduces the
amount of oxygen reaching the foetus’ developing tissues
...
It can also delay
(h) Explain the use of foetal ultrasonography, amniocentesis and chorionic villus sampling
the foetus’ growth and increase perinatal mortality-that is, death of the
(CVS) for detecting named disorders and assessing foetal well-being
...

disadvantages of each technique should be outlined;
Ultrasonography (see learning outcome (f))
The use of ultrasound scan to obtain a picture of structures inside the body is called
ultrasonography
...

Amniocentesis
The test involves using a needle to take a small sample of amniotic fluid
...
The DNA in cells from the amniotic fluid can be tested for genetic
diseases by cytogeneticists
...
It is possible to do the
test earlier, but there is a higher risk of causing a miscarriage if this is done
...
The needle is
narrow (less than 0
...
The procedure is monitored by ultrasound scanning
...
It has been estimated that miscarriage
rate is increased by about 1 to 2%
...
) This is a slightly greater risk than for amniocentesis, but probably less risky
than amniocentesis before 15 weeks
...


Prenatal test
amniocentesis
(i) outline how a karyotype is produced and used to determine fetal sex and to diagnose
chromosomal mutations, limited to Turner’s and Klinefelter’s syndromes;

A karyotype is a picture of all the chromosomes in
a cell, organised into their pairs so that they can
easily be counted
...
At this
stage, they are at their shortest and fattest, and so
are relatively easy to see
...
First of all, cells are collected from the foetus by amniocentesis or chorionic villus sampling
...
The cells are treated with a chemical from kidney beans, called phytohemagglutin
...

3
...
This stops the
spindle being formed, so they cannot get any further through the process of mitosis
...

4
...
They absorb water by osmosis, and swell up,
which helps to spread the chromosomes out
...
Next, the cells are stained so that the chromosomes show up clearly
...
They are viewed through a microscope, and many photographs are taken of them
...
Each chromosome is identified, and its image placed in an appropriate position
within the karotype
...


(j) explain how chromosome mutations such as Turner’s and Klinefelter’s may occur during
meiosis (with reference to non-disjunction only)
...
For
example, one of the daughter cells might get two copies of a chromosome, while the other
daughter cell gets none
...
Or part of a chromosome might break
off and reattach to a different one
...

Klinefelter’s syndrome
If an error occurs during a cell division in a woman’s ovaries, then one of her eggs may end up
with two X chromosomes
...
The baby is a boy, with Klinefelter’s syndrome and his cells contain 47 chromosomes
...
The extra X chromosome affects the development of
the testes
...
So there is a high chance that an XXY man had of being
infertile
...
They are less likely than other boys to have an IQ above 110
...
This results when one of the
gametes did not carry a sex chromosome, producing a zygote with only one X chromosome
instead of the usual two
...

Many of her body systems will be affected
...

For more information on Turner’s syndrome

2
...
2 The Developing Infant
(a) describe methods of measuring infant growth by monitoring changes in weight, height and head
circumference;

Measuring infant weight
A naked baby is placed on scales that are specially designed for
weighing babies
...

Experience is needed in handling babies, as they can become
distressed by being handled by someone other than a parent
...
Repositioning and
reweighing are done again, so there are three readings altogether
...
1 kg between these
readings
...

The mean of two reading that are closest together is calculated
...

If the first method is not possible because the infant is too active,
the mother is asked to stand on adults scales
...

The procedure is repeated twice more
...


Measuring infant height (length)
The height of the infant is measured with the lying on specially designed
equipment
...
A ruler in the device is
used to take a reading
...
It should be dressed in light underclothing
...
Plastic tapes are often used,
designed so that one end of the tape can be inserted into the other end to
take a reading
...


(b) outline the importance of: carbohydrates, lipids, essential fatty acids, proteins essential amino
acids; calcium, iron, phosphorous; vitamins A C and D in maintaining healthy growth in infants;

Carbohydrates and lipids are needed for energy
...
These is considerable
evidence that the presence of certain kinds of fatty acids in the diet can have a significant effect on
brain development
...
A large component of these cells is protein, so a
growing child needs plenty of protein in the diet
...

Iron is needed for the formation of haemoglobin in the millions of new red blood cells which are
being formed
...


Vitamin C is a highly effective antioxidant, and necessary in the biosynthesis of many
important molecules like collagen and dopamine
...


Vitamin D: enzyme in the liver convert vitamin D into active vitamin D which act as a hormone to
stimulate epithelial cells in the intestine to absorb calcium

healthy eating information

(c) describe with the aid of diagrams the pattern of growth during the human life cycle;
The Human Life Cycle

Human growth is divided into four phases:
Fetal growth when the growth rate is very high
Infancy and childhood when is very rapid at first and then the rate of growth slows down to a
steadier rate
Adolescence when there is a rapid growth spurt due to puberty
Adulthood when the growth rate falls to zero, as the person’s body mass or height stop increasing
...

c
a

a- growth rate increasing
d

b -Shows when growth is most rapid
c- Growth rate decreasing
d- Zero growth (reached maturity)

Relative growth rate
Relative growth rate takes into account existing
size of organism
...
Comparison of relative
growth rate can show most favourable
conditions for rapid growth when grown under
different conditions
...
Different organs show patterns of
growth that are not the same as the overall pattern
...

One of the most noticeable things about an infant is that the head is much larger in proportion to
the rest of the body than in an adult
...
This is relate to the growth of the nervous tissue inside it forming the brain
...
This system
is involved in the immune response
...
After birth, the
child’s antibody levels fall- although it will receive some from its mother if she breastfeeds
...
It is not until it is 12 to 20
months old that the lymphatic system is fully formed and the child’s body can mount a full immune
response
...
They do begin to develop
while the foetus is in the uterus and indeed, by the time a girl is born, she will already have large
numbers of eggs in her ovaries
...
In boys, this is somewhere between the ages of 8 and 16 years, while in girls it
normally happens between 7 and 15
...
3
...
Drug treatments exploit the differences between
eukaryotic cells & prokaryotic and viral pathogens
...

Plants have historically provided a valuable source of medicines and
plant biodiversity should be preserved in the face of rapid global
change and loss of habitats
...
g
...
iayork
...
jpg

d) Describe, with the aid of diagrams, the structure of the Human Immunodeficiency Virus
(HIV)

e) Describe the symptoms, causes & means of transmission of tuberculosis (TB) & HIV/ AIDS

Symptoms of Tuberculosis (TB )  Excessive, persistent coughing
 Blood-stained mucus
 Chest pains
 Breathlessness
 Fever & night sweats
 Loss of appetite
 Weight loss

Causes of TB - Tuberculosis (TB) is caused by the bacteria Mycobacterium tuberculosis
...
This shows up as ‗foggy‘
patches on X-ray

TB lung x-ray of patient with resistant TB
news
...
co
...
/hi/newsid_4528000/4
528543
...
vbi
...
edu/pathinfo/pathogens/Tuberculosis_2

...
However, many people do not experience
these symptoms in the first 6 weeks to 3 months after infection
Symptoms appearing some time after being infected with HIV & now
suffering from AIDS:
chronic yeast infections or thrush (yeast infection of the mouth)
Fever and/or night sweats
Easy bruising
Bouts of extreme exhaustion
Unexplained body rashes
Appearance of purplish lesions on the skin or inside mouth
Sudden unexplained weight loss
Chronic diarrhoea lasting for a month or more

Short video on symptoms of HIV infection
http://technorati
...
com%2Fwatch%3
Fv%3DC_94fmY2KL4

Cause of HIV / AIDS - Acquired Immune Deficiency Syndrome (AIDS) is a disorder is
caused by a virus (Human Immunodeficiency Virus – HIV)

HIV reproduces within T helper cells known as T4 or CD4 cells as well as in macrophages
and brain cells too

HIV infects and impairs the function of T helper cells Tthese cells activate other
lymphocytes and if the number of T helper cells falls, then so does the immune response to
infection

As a result in the drop in T helper cells the body is unable to protect itself from a whole range
of bacteria (e
...
causing tuberculosis), viruses (e
...
herpes), fungi (e
...
causing oral thrush
and a rare form of pneumonia) and cancers (e
...
Kaposi‘s sarcoma)

HIV infection leads eventually to a decrease in the number of circulating T helper cells
...
(HIV+ people can still pass on the disease though!)
Animations of HIV infecting a T helper cell
http://www
...
org/channel/courses/biology/archive/animations/hires/
a_hiv2_h
...
com/videos/youtube
...
com/videos/youtube
...

2
...

4
...
g
...
g
...
g
...
g
...
They possess a gene on their plasmid DNA which codes for an
enzyme that inhibits the function of an antibiotic
...
tuberculosis in existence
...
In addition, some of
the chosen antibiotics have unpleasant side effects and this may discourage patients
from completing the course
MRSA stands for methicillin-resistant Staphylococcus aureus & is an example of a
‗superbug‘ as it carries multiple resistant genes on its plasmid DNA

MRSA is on the increase in hospitals for the following reasons:

25% of the population carry S
...
dshs
...
tx
...
/mrsa/picpage
...
sumanasinc
...
plantlife
...
uk/international/plantlife-medplants
...
The DNA is then cut up using restriction enzymes & the
fragments produced can then be separated using gel electrophoresis
...
bbc
...
uk/1/hi/sci/tech/7221946
...
google
...
nature
...
jpg&imgrefurl=http://nature
...
cfm&h=245&w=225&sz=16&hl=en&st
art=4&um=1&tbnid=lv2apE6MrMHvFM:&tbnh=110&tbnw=1
01&prev=/images%3Fq%3Dplant%2BDNA%2Bbanding%2
Bpatterns%26um%3D1%26hl%3Den%26safe%3Dstrict%26
sa%3DG

k) Discuss the role of seed banks in the ex situ conservation of rare plant species or
plant species extinct in the wild



Conservation of rare, endangered and medicinal plants should be a priority as the
human population continues to expand, threatening natural habitats



Ex situ conservation is necessary where habitats have been destroyed



Seed banks are an example of the ex-situ conservation of rare, endangered and
medicinal plants



Seed banks are a central store of many different species of plant seeds
...
These seeds
are viable for many years as long as they are dehydrated to about 5% water and then
stored at -20c
...




Recalcitrant seeds – about 20% of plant species (of which 70% are tropical plants)
have seeds that cannot be dehydrated and frozen
...
The Millenium Seed Bank hopes to have seeds from 10% of the
world‘s estimated 240,000 plant species by 2010
...
bbc
...
uk/1/hi/sci/tech/4605398
...
guardian
...
uk/science/2006/jun/20/food
...
3
...

Childhood vaccination remains a contentious issue as do issues
surrounding the availability of vaccines, for example, influenza
Vaccination is also key to controlling infections in individuals who work
or holiday where infectious diseases are endemic
...
g
...
thevaccinesite
...
htm

c) Explain what is meant by the term immune response, distinguishing between the non-specific
and specific response
The immune response is how your body recognises and defends itself against bacteria,
viruses, and substances that appear foreign and harmful to the body


An immune response is stimulated in the body by particular antigens



Antigens (means antibody generator) are foreign substances (e
...
proteins,
glycoproteins and polysaccharides) which stimulate an immune response (e
...
the
production of antibodies)
...
The non-specific response
2
...
This type of
immunity involves mechanisms that prevent entry of pathogens into the body and
mechanisms to destroy pathogens that enter into the body
The non-specific response will be the same regardless of the type of antigen it
encounters

The non-specific defence mechanisms of the body include:
Skin

Forms a continuous layer/barrier, preventing entry of microbes
Continued loss of skin carries microbes away from body surface
If skin becomes damaged, scar formation occurs, preventing entry of microbes

Tears

Contain the enzyme lysozyme, which hydrolyses bacterial cell walls
Wash away microbes from surface of the eye

Acid

Acid environment of the stomach, urethra and vagina, destroys microbes

Saliva

Contains the enzyme lysozyme, which hydrolyses bacterial cell walls

Mucus and cilia

Mucus forms a sticky layer over air passages and urino-genital tract, trapping microbes
...

Mucus also contains the enzyme lysozyme, which hydrolyses bacterial cell walls



The specific response is so named because it tailors its attack to a specific antigen
...
merck
...
html
d) Describe the origin, maturation and mode of action of phagocytes and
lymphocytes in the non-specific and specific immune response



Lymphocytes are the most important type of white blood cell involved in specific
immunity



There are 2 main groups of white blood cells (leucocytes) which are involved in
immunity to infection;




Phagocytes
Lymphocytes

Non- specific Immune Response
Example of
cell

Picture of cell

Origin of cell

Maturation site
of cell

Function of cell

Bone marrow

Type of
white blood
cell

Blood stream

Phagocytosis

Tissues of
organs

Phagocytosis (see above)
...


(myeloid
precursor cells)

Other types
of
leukocytes
basophils

Inflammation & allergic response
Bone marrow
(haematopoietic
stem cells)

Bone marrow

Specific Immune Response

Type of
white blood
cell

Example of cell

Picture of cell

Origin of cell

Bone marrow
monocyte

Maturation
site of cell

Function of cell

Blood
stream

Phagocytosis & aiding in
generating the specific
immune responses by antigen
presentation

Tissues of
organs

See above

(haematopoietic
stem cells)

macrophage

Bone marrow
(haematopoietic
stem cells)

neutrophils

Phagocytosis of pathogen in
response to the pathogen
being coated in antibodies
produced by Plasma B cells
...
Antibodies
enable phagocytosis to
happen more easily

B lymphocytes
Recognize specific antigen,
and when that happens divide
further to produce more
plasma and memory cells
B Memory cell
B&T
Lymphocytes
T lymphocytes
Helper T cells

Bone marrow

Cytotoxic T cells

(all T cells
originate from
hematopoietic
stem cells)

Memory T cells
Regulatory T cells

Thymus

Helper T
once activated, they divide
rapidly and secrete small
proteins called cytokines that
aid the immune response
Cytotoxic T
Destroy virally infected cells,
tumour cells & transplanted
organs
Memory T
Retain information about a
specific antigen & on reexposure to that antigen will
rapidly divide to produce more
memory T cells & helper T
cells
Regulatory T
Shut down the T cell response
towards the end of the immune
response

e) Compare and contrast the modes of action of B and T lymphocytes in fighting infection



B lymphocytes - The main function of B cells is to make antibodies against
antigens
...
B cells are an essential
component of the specific immune response



B lymphocytes are part of the Humoral Immune Response



T lymphocytes – there are several types of T cells, each with a specific function
(see table above)
...
youtube
...
youtube
...
youtube
...
Protection from passive
immunity diminishes in a relatively short time, usually a few weeks or months
...

Injections of a vaccine containing antigens generally produce life-long
immunity to the pathogen whereas injection or exposure to another persons‘
antibodies provides short lived immunity

Natural immunity
http://www
...
org
...
asp
Great site for immune system
http://www
...
com/immune-system/iss16
...
the specific B & T cells to encounter a particular antigen
2
...
g
...
immunisation
...
uk/About_Immunisation/Science/Herd_immunity_-_animation
Informative website on vaccinations
http://www
...
nhs
...
The variable region includes the ends of
the light and heavy chains



The variable region differs considerably amongst all antibodies, enabling an antibody
to be specific to a particular antigen



Antigens bind to the variable region on the antibody



Antibodies are divided into 5 major classes, IgM, IgG, IgA, IgD, and IgE, based on
the structure of their constant region and on the role they play in an immune
response



The constant region is the same amino acid structure for all antibodies belonging to
that particular class of antibodies

Diagram showing the region of the antibody which
binds to the antigen



Antibodies function by binding pathogens together, in a process called
agglutination



This then enables phagocytes such as macrophages to engulf the pathogens
...
g
...
blood
...
uk/pages/blood_type_calculator
...
If Rhesus factor (also called
antigen D) is present you are described as being RhD positive & if not your blood
type is RhD negative



Rhesus factor is combined with the ABO system to give an overall blood type e
...
A+
(blood group A and Rhesus factor is present) or blood type A- (blood group A and
Rhesus factor is absent)



And so it goes for groups B, AB and O



About 84% of the population is Rh positive



Rh- people do not have Rhesus antibodies in their blood plasma but can develop
these antibodies if they receive blood from a Rh+ person or if they are pregnant with
a Rh+ baby



Rh- people can only receive blood from a Rh- person



Rh+ people can receive blood from both a Rh+ and Rh- person

k) outline the biological problems involved in developing and using a vaccine against HIV



Some scientists argue that no vaccine will ever stop HIV
...
This may mean that a vaccine would have to trigger
both B & T cell immune responses to protect an individual



Selection of volunteers for HIV vaccine trial

Excellent newspaper article on recent HIV vaccine trial
http://www
...
com/article
...
com/videos/youtube
...
In addition, there is concern that young girls
may not take precautions and put themselves at risk of contracting other sexually
transmitted diseases such as HIV, Chlamydia and gonorrhoea or getting pregnant



American sites on HPV vaccine
http://www
...
gov/std/Hpv/STDFact-HPVvaccine
...
youtube
...
youtube
...
This response can occur if someone currently has TB or if they
were exposed to it in the past



The skin test is based on the fact that infection with M
...
These lymphokines
induce a response which is visible as a hard, raised area with clearly defined margins
at and around the injection site



Most often the tuberculin test is administered by injecting 0
...
medicinenet
...
htm

Picture showing injection site of tuberculin

The test for HIV:






The 1st type of test is the HIV antibody test
...
Most people
develop detectable HIV antibodies within 6 to 12 weeks of infection and this HIV test
is the most commonly used one
The 2nd type of test is an antigen test
...
The antigen
on HIV that most commonly provokes an antibody response is the protein P24
The 3rd type of test is a PCR test (Polymerase Chain Reaction test)
...
avert
...
htm

Excellent UNICEF video on PCR HIV test
http://www
...
com/watch?v=9WMkKo4nm8g&feature=related

2
...
3 The Future of Infectious Disease Control
Context & exemplification:
 Organisations such as the Health Protection Agency (HPA) in the UK
and the World Health Organisation (WHO) monitor the spread of
infectious diseases by collecting data and, based on this, provide
guidance and advice to the public and to governments
...
healthhaven
...
cce
...
edu/profiles/
play
...
html
2170052336504395801&q=you+tube+epidemiology
&ei=EzRSSKe6C4H2qAOPrJSrDA
 Morbidity – from the latin ‗morbidus’ meaning sick or unhealthy


Morbidity is a word used to describe a diseased condition or state and or the
incidence of a disease in a population



Mortality – a measure of the number of deaths in a given population, per unit of time
e
...
the total number of deaths per 1000 people per year

Website showing morbidity statistics for heart disease in the UK
http://www
...
org/topic
...
wikipedia
...
heartstats
...
asp?id=17

b) Interpret data to assess the global impact & importance of TB & HIV infection




When interpreting epidemiological data it may be necessary to repeat the study &/or
continue the study over a longer period of time before conclusions can be drawn
Below is a good example of data presented in a graph which MUST be interpreted
alongside the statistical evidence of the study before a conclusion can be given

Graph showing comparison rates of TB infection according
to age groups over 2 periods of time in New Zealand
http://www
...
org
...
The burden of
disease is very unevenly
distributed across the population
with marked ethnic inequalities
(not shown on graph)

With any disease that is on the increase, one has to consider not only the impact that
disease may have on the general economy for that country but also the impact
worldwide e
...

1
...
Evidence suggests that there is between 0
...
4 percent less growth in
the economy for every 10 percent higher incidence of tuberculosis
...
4 and 2
...
This is because HIV results in higher morbidity and higher
mortality in particular age groups



In societies that experience rising adult mortality, the passing on of acquired skills
and knowledge diminishes
...
undp
...
htm

This graph shows that as the
rates of HIV infection increase,
the economy of the country
decreases



Many studies have concluded that HIV infection is fuelling the world wide rise in TB
infections but that for a number of years HIV & TB prevention & treatment strategies
have been kept separate



The WHO is developing a strategy to tackle the infections jointly particularly in
countries where TB leads to early death in those already infected with HIV
...
tbalert
...
pdf

(c) Explain what is meant by the term notifiable disease



Notifiable disease – A specified infectious disease which is required under the Public
Health (Infectious Diseases) 1988 Act and the Public Health (Control of Diseases)
1988 Act to be reported to the Local Authority



Statistics on notifiable diseases are collected by the Health Protection Agency



Such diseases include:
1
...
Measles
3
...
Rabies
5
...
Plague

Good website on notifiable diseases
...
patient
...
uk/showdoc/40000306/



Main purpose behind reporting & monitoring of these diseases is to limit the spread
of infection via emergency vaccination programmes or prophylactic use of antibiotics



In addition, epidemiologists are able to trace the incidence of a disease over time

d) Discuss the social, ethical, economic and biological factors involved in attempts to control
and prevent TB and HIV/AIDS

Prevention & control of TB

Social & ethical factors:

1
...
Supervising treatment, e
...
is the
patient taking the prescribed drugs?
3
...
Could the person infected with TB also be infected with HIV
without
knowing it?
5
...
Can the person infected with TB continue to work?
2
...
Is there money available for the treatment of patients with TB?
Who is paying for the treatment of the disease? This will include
types of drugs required and for how long
4
...
Will the person require improved living accommodation?
Biological factors:

1
...
Identifying source of infection e
...
through contract tracing, taking
personal history which may include migration / travelling details
3
...
Treatment of disease including monitoring of symptoms and
detection of drug resistant TB
5
...
Informing authorities of person with a notifiable disease
Very informative Canadian website on TB
http://www
...
gc
...
html

Prevention & control of HIV/AIDS
Social & ethical factors:

1
...
g
...
Other US &
European campaigns have since targeted drug users,
heterosexuals (young & middle-aged) whereas in Africa the
highest rate of infection occurs between heterosexuals having
more casual sex than is seen in other populations
2
...
g
...
All factors which may encourage the spread of disease or
prevent a person receiving the necessary medication
3
...
Tracing contacts

Economic factors:

1
...
What percentage of the country‘s labour force is infected and what
ages are most affected?
3
...
Can condoms or free needles be provided to prevent spread of
HIV?
5
...
HIV test
2
...
Administering of drug treatment, measuring viral load in the blood
of the patient, treatment of illnesses as disease progresses
4
...
Explaining to the patient the nature of the disease

Excellent website on HIV prevention worldwide
http://www
...
org/hivprevention
...
Has the pathogen responsible for the disease been identified?
2
...
e
...
How is the pathogen transmitted?
4
...
e
...
Which people are most susceptible to infection?
6
...
g
...
What is the infection rate, survival rate of this disease?
8
...
wikipedia
...
4
...

The cost to the NHS of non-infectious diseases is increasing, with spending on prevention, treatment
and management of these conditions accounting for a large proportion of the NHS budget
...

Context and exemplification Assessable learning outcomes
• An understanding of the risk factors associated with CHD allows individuals to take more
responsibility for their own health and well-being
...

• There are many surgical procedures for the treatment of CHD
...
This means it
can not be passed on from person to person
...

2) Type 2 diabetes

An infectious disease is a disease caused by a pathogen (another organism), e
...
a
virus or bacteria
...

Examples are;
1) Tuberculosis which is transmitted by a bacteria called Mycobacterium
tuberculosis
2) HIV which is transmitted by a retrovirus
...

There are risk factors which can damage the lining of the arteries
...

Both lead to the development of coronary heart disease
...
dic
...
cl/~hechavez/athero
...

Atherosclerosis begins when the lining is
injured or diseased
...

Inside the lining, they are transformed into
foam cells, which are cells that collect fatty
materials, mainly cholesterol
...

Connective and elastic tissue materials also
accumulate there, as may cell debris,
cholesterol crystals, and calcium
...


As they grow, some plaques thicken the artery's wall
and bulge into the channel of the artery
...
Other plaques do not block the
artery very much but may split open, triggering a
blood clot that suddenly blocks the artery
...
The pain or
discomfort that happens as a result is called
angina
...

This occurs when the diameter of the artery
lumen has decreased by 50% or more
...
The
part of the heart muscle supplied by this artery
loses its blood (and oxygen) supply
...
(The word
'infarction' means death of some tissue)
...
If
a smaller branch artery is blocked, a smaller
amount of heart muscle is affected
...

The pain is continuous
...
nlm
...
gov/medlineplus/tutorials/angina/htm/index
...
nlm
...
gov/medlineplus/tutorials/heartattack/htm/_no_50_no_0
...
This
is known as a cardiac arrest
...


(d) Describe first aid treatment to a conscious person suffering a suspected heart attack;
First aid aims to make the casualty comfortable and get emergency help
...
Sit casualty in a supported position with knees bent
2
...
Allow the casualty to take any medicine they have for an existing heart problem or
ask them to slowly chew on an aspirin to reduce the risk of a second heart attack
...
Monitor the victims pulse, alertness and breathing
...
Trained
first aiders can carry out CPR

Cardio-Pulmonary Resuscitation (CPR)
 If you have someone with you, send them to dial 999 (or 112) for an ambulance immediately
...


Give 30 chest compressions
 Place heel of your hand in the centre of the chest
...

 Keeping your arms straight and your fingers off the chest, press down by 4-5cms
...

 Repeat the compressions 30 times, at a rate of 100 per minute
...








Ensure the airway is open
...

Take a deep breath and seal your lips around the casualty‘s mouth
...

Remove your mouth and allow the chest to fall
...


Continue resuscitation, 30 compressions to 2 Rescue Breaths
...

 The casualty breathes normally or
 You become so exhausted that you cannot carry on
...
sja
...
uk/sja/first-aid-advice/life-saving-procedures/cpr-for-adults
...





It is used when the victim has become unconscious due to an abnormal or ‗fluttering‘
heart rhythm known as ventricular fibrillation
...


Aspirin is given to prevent the role of platelets in the blood clotting process
...
There are many factors that influence this distribution,
E
...
:


1)
2)
3)
4)



Environment – who around you smokes, availability of healthy food
...

Social – peer pressure, low income, education
Genetic – certain groups of people will have similar genes that give them a
predisposition to developing CHD
...
This can then be used to help prevent further cases of CHD
...
http://www
...
com/heart/

(h) Identify the risk factors associated with CHD including: diet, blood pressure, exercise,
smoking, genetic influences;
There are many risk factors that might influence the possibility of developing CHD
...
They are bonded together by a
condensation reaction (which produces water) to form an ester
bond
...

A saturated fat contains only single bonds between the carbons in the fatty acid
chain and so contain the maximum number of hydrogen atoms possible
...





Cholesterol is used to synthesise lipids
...

Lipids are hydrophobic and therefore not soluble in water
...
These are tiny balls made up of different
proportions of protein, lipid and cholesterol molecules
...
Lipoproteins are classified as High Density Lipoproteins
(HDL) or Low Density Lipoproteins (LDL)
...
HDL‘s seem to remove cholesterol from the tissues and transport it back to
the liver
...

A diet rich in saturated fats may lead to a high LDL concentration and hence the risk
of CHD
...


Blood pressure





Hypertension is when a persons resting blood pressure is
continuously high
...

The heart is also put under strain as it has to cope with more blood flowing threw it at
higher pressures
...

A diet high in salt can increase hypertension owing to the lowering of blood water
potential
...


Exercise


The benefits of aerobic exercise include a reduction in LDL and blood
pressure
...
It increases the development of
atherosclerosis as the linings of the arteries are damaged
...

 These genes do not mean a person will get CHD but they may have a
predisposition to it
...

 Genetic screening may allow individuals to adapt their lifestyles if they are aware
that they have a genetic predisposition to CHD
...
sciencemag
...

It is nevertheless a crude index that does not take into account the distribution of
body fat, resulting in variability in different individuals and populations
...

Individuals with the highest waist-to-hip ratio appear to have the highest heart
disease risk
...


High BMI but low waist to hip
ratio has a lower risk of CHD

(j) Outline medical treatment for CHD to include coronary by-pass surgery, angioplasty and
heart transplants;
 Coronary bypass surgery is used to re-route the blood supply around the parts of the
coronary arteries that have become blocked
...

http://www
...
com/cholesterol/videos-44022-47
...
Involves inserting a small
balloon into the partly blocked artery through a catheter
...
The
width of the lumen is restored and the balloon is removed
...




Heart transplantation is a surgical procedure to remove a damaged or diseased heart
and replace it with a healthy donor heart
...

o A cut is made through the breast bone
o The patient's blood is circulated through a heart-lung bypass machine to keep
the blood oxygen-rich
...

o The heart-lung machine is disconnected
...

o Anti rejection drugs are taken to prevent the patients‘ immune system
rejecting the new heart
...
K and is a very costly
disease
...
K
...
9 billion a year
...

 Around 45% of this is due to direct health care costs, 40% to production losses and
16% to informal care
...
It is predicted that the prevalence of
diabetes will increase by 15% over the next 20 years as a consequence of rising
obesity levels
...
heartstats
...
chapter13
...
heartstats
...
chapter3
...

Interventional procedures, technology appraisals, public health intervention guidance,
public health programme guidance and clinical guidelines are the main areas that are
covered for a wide range of health issues
...


http://www
...
org
...
jsp?action=byTopic&o=7195&set=true

2
...
2 Lung Disease
Context and exemplification Assessable learning outcomes
• Lifestyle choices and modern living can have an adverse effect on the respiratory system
...
E
...

Emphysema and chronic bronchitis



Acute is a disease that has a rapid on set and is usually short in duration
...
g
...


(b) Describe the short-term and long-term effects of smoking on the respiratory system, with
reference to COPD (Chronic Obstructive Pulmonary Disease) and lung cancer;

Short term effects of smoking
1
...
It forms
carboxyhaemoglobin which reduces a
smokers‘ ability to carry oxygen by up to 15%
...
After smoking a cigarette carbon monoxide
also causes an increase in blood pressure and
the heart rate will increase by about 20 beats
per minute to try and deliver enough oxygen to
the tissues of the body
...
Tar is a very sticky substance that lines the bronchi, bronchioles and alveoli
...
The mucus that is normally removed
by the cilia stays in the lungs providing a perfect place for microorganisms to grow
...
Tar also stimulates the goblet cells to produce more mucus
...
google
...
smokingisjuststupid
...
jpg&imgrefurl=http://www
...
com/&h=428&w=451&sz=36&hl=en&start=87&um=1&tbnid=Pwe3vQxBqmcvnM:&tbnh=121&tbnw=127
&prev=/images%3Fq%3Dmucus%2Bfilled%2Bbronchi%2B%26start%3D80%26ndsp%3D20%26um%3D1%26hl%3D
en%26safe%3Dstrict%26sa%3DN

Chronic bronchitis
Diagrams: the cilia (H) are attached to columnar cells, labelled (I)
...

The bottom layers of cells, labelled (L) are the basal cells
...
Not only are fewer cilia present but the
ones that are still functioning are doing so at a much lower level of efficiency
...
Mucous starts to build up in
the small airways making it harder for the smoker to breathe and causing the
characteristic smokers cough in order to clear out the airways
...


Emphysema
 Irritants and infections in the lungs cause inflammation
...
They produce an enzyme called elastase which helps them
break through the elastin fibres surrounding the alveoli
...

 In addition, cigarette smoke triggers the release of damaging particles called oxygen
free radicals (or oxidants) that deactivate alpha-1 antitrypsin (AAT), a protein that
neutralizes damaging cells and protects the lung from destruction
...
There is
progressive destruction of
alveoli and the surrounding
elastin tissue that supports
the alveoli
...
There
is a reduced surface area for
gas exchange and air is
trapped in the lungs as
elastins normal function is to
recoil when stretched forcing
air
...

The damage is not reversible
...

Smoking is the main cause of COPD
...
Most sufferers of COPD are smokers or used
to be smokers and between 80 - 90% of all deaths from COPD are due to smoking
...
p53 is a tumour suppressor gene that controls cell division
...
As the
epithelial cells divide uncontrollably they form an irregular mass of cells known as a
tumour
...

If a smoker quits before cancer actually starts, even if the cells are in a precancerous
state, the process is highly reversible
...
Even if cilia have been destroyed and not present for years, the lining
tissue of the windpipe will start to repair
...
But if a smoker waits too long and cancer starts, it may
be too late to save his or her life
...


Causes of asthma
Allergic - usually before the 40
years of age
...

Exercise induced – any age
Nocturnal – all ages

Occupational

Triggered by allergens e
...

pollen, dust
...
g
...


Symptom




The lining of the airways become inflamed and release more mucus, blocking the airways
...

Main symptom is wheezing as it’s difficult for air to escape from the alveoli
...
Beta-agonists





Beta agonists interact with beta receptors on the surface of a variety of cells that may
play a role in asthma pathogenesis
...

Beta – agonists are usually inhaled but they can also be administered as syrup or in
tablet form
...
Steroids







The steroids used to treat asthma are called corticosteroids
...
In
fact, asthma steroids are like the steroids produced naturally by our bodies to deal
with inflammation
...
This also reduces the risk of side effects elsewhere in the body
...
Once the airways are
less inflamed they are less sensitive to triggers such as cigarette smoke and viral
infections
...


2
...
3 Diabetes
Context and exemplification Assessable learning outcomes
• The incidence of type 2 diabetes is growing rapidly in developed countries
...


(a) Distinguish between type 1 (insulin dependent) and type 2 (non-insulin dependent)
diabetes (details of insulin action are not required);
http://www
...
com/diabetes_mellitus/page3
...

Little or no insulin is produced so
blood sugar levels can‘t be controlled
...


Type II Diabetes






(b) describe the link between type 2 diabetes and diet
...

Increased body mass may mean that there is
either an insufficient amount of insulin
produced or further insensitivity of the cells to
insulin
...

Controlled by diet (eating of complex
carbohydrates) and exercise
...

Genetic factors may also contribute –
there is a higher number of cases of
type II diabetes amongst Asian
children in the UK
...

(Ref: http://www
...
com/diabetes/diagnosis
...
A value above 140
mg/dl on at least two occasions typically means a person has diabetes
...


[2] The Oral Glucose Tolerance Test
An oral glucose tolerance test is one that can be performed in a doctor's office
or a lab
...

An initial blood sugar is drawn and then the person is given a "glucola" bottle
with a high amount of sugar in it (75 grams of glucose), (or 100 grams for
pregnant women)
...

In a person without diabetes, bllod glucose levels rise but quickly return to
normal
...


(d) outline the use of biosensors for monitoring blood-glucose levels;


People with diabetes mellitus need to constantly monitor their blood glucose levels in
order to detect fluctuations in glucose level that could lead to hyperglycaemia (high
blood glucose levels) and hypoglycaemia (low blood glucose levels) so as to control
the disease
...
A drop of blood is placed on the test strip and
blood glucose concentration measured by an electrode
...
Glucose
oxidase is one of the possible enzymes that a biosensor test strip can use
...
The
bio-sensor works by making tiny pores in the skin, through which the interstitial fluid
can rise

http://www1
...
edu/college/research/14880
...


This graph clearly shows a link between age and the incidence level of diabetes, but look
carefully at the other information you can gather from it
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g
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Can you think of a possible reason for the differences at each age?

The distribution of diabetes is however more complex than just age and gender
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These people are all living in NSW, Australia
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For
example the incident rate of diabetes in the Lebanon is fairly low but those who migrated to
NSW show quite a high incidence level
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The
same is believed to happen as people migrate to more affluent countries
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health
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gov
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