14-19 Learning Core Development Programme Laura Blacoe Connah’s Quay High School.
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Transcript of 14-19 Learning Core Development Programme Laura Blacoe Connah’s Quay High School.
14-19 Learning Core Development Programme
Laura BlacoeConnah’s Quay High School
Aim
To help pupils understand more about the importance of the increasing
knowledge of genetics and how and why people inherit genetic disorders.
Lesson Objectives
We are learning:
That genetic information is found in the nucleus of every cell in the body and determines characteristics.
That genetic information is inherited from parents and that in each pair of chromosomes one is inherited from the mother and one from the father.
That diseases and disorders can be inherited.
Lesson Outcomes
What I am looking for:
TYC describe what DNA, genes and chromosomes are and how they determine characteristics.
TYC describe how genetic information is inherited and use genetic cross diagrams to determine the possible genotype of offspring.
TYC describe the symptoms of 4 different genetic diseases and explain how they are inherited. Also, predict possible genotype of offspring using genetic cross diagrams.
Sexual Fertilisation
Human Chromosomes
Using letters to represent alleles
Dominant alleles = Capital letterRecessive alleles = Lower case letter
of the dominant allele
Black hair allele = BRed hair allele = b
Genetic Crosses
B
b
B B
BB BB
Bb Bb
Black Hair Black Hair
Black Hair Black Hair
B
b
b
B
BB Bb
bb Bb
Mum’s Genotype
Dad
’s
Genoty
pe
Activity 1 – Huntington’s Disease
Huntington’s disease is a fatal disease that affects the nervous system. It is caused by a defective allele on chromosome 4. It affects both men and women and makes the body shake uncontrollably.
Faulty allele = HNormal allele = h
Answers to activity 1
H
h
h h
Hh
hh hh
Hh
Extension Activity
John and Karen have both discovered that they have the genetic disorder Huntington’s disease.
But, they already have 2 children together. Explain to them (using genetic cross diagrams) the possibilities of their children’s genotype.
Answers to extension activity
H
H
H H
HH HH
HH HH
H
h
H H
HH
HhHh
HH
HhHH
H h
H
h hhHh
Activity 2 – Cystic Fibrosis
Cystic Fibrosis is a genetic disorder caused by a recessive faulty allele. C = Normal allelec = Faulty alleleCystic Fibrosis affects the cells membranes and causes the production of excess mucus in the respiratory organs and digestive system.
C
c
C
c
Cc
Cc Cc
Cc
Activity 3 – Sickle Cell Anaemia
Distribution of Sickle Cell sufferers
S
s
S s
SS Ss
Ss ss
Activity 4 - HaemophiliaSymptoms: Main symptom is that
blood does not clot properly.
Even small cuts and tooth extractions can be lethal due to blood loss.
Small knocks can cause internal bleeding and big bruises and joints may also bleed.
Treatment
The condition can be treated quite successfully by regular injections of the clotting factor – FACTOR 8.
Haemophilia – The sex-linked Gene
• Sex linked means only present in males or females.
• Haemophilia is only present in males.
• Sex-linked conditions occur when the there’s a defective allelle on the X-chromosome.
• Any recessive genes on the man’s X-chromosome will express themselves because their equivalent gene is missing form the shorter Y-chromosome.
There are 5 possible combinations for the blood clotting allele
Normal Male XHY
Haemophiliac Male
XhY
Normal Female
XHXH
Carrier Female
XHXh
Zygote does not develop
XhXh
You can’t have a male carrier without them having the disease.
There are no female sufferers because the offspring don’t develop.
H = Normal
h = Haemophiliac
XHY XHXh
XH Y XH Xh
XHXh
XHXH XHY XhY
Parent Genotypes
Normal Female
Carrier Female
Normal Male
Haemophiliac Male
Genetic Cross Diagram for Haemophilia