Human reproduction answers
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Mr A Lovat
1
Genetics
Chromosome
Mendel
Nucleus
Testicle
Homologous
Dominant
Recessive
Allele
Fertilisation
Cell Division
Objectives
I should be able to…
3.13 understand that the nucleus of a cell contains
chromosomes on which genes are located
3.14 understand that a gene is a section of a molecule
of DNA and that a gene codes for a specific protein
3.15 describe a DNA molecule as two strands coiled to
form a double helix, the strands being linked by a
series of paired bases: adenine (A) with thymine (T),
and cytosine (C) with guanine (G)
3.16 understand that genes exist in alternative forms
called alleles which give rise to differences in
inherited characteristics
Homework
SEE WEEBLY for link
Watch the video:
https://www.youtube.com/watch?v=d7ET4bbkT
m0
Once you have watched the video, write a short
story charting how we discovered the structure
of DNA
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Put these terms in size order & give an
example!!!
Smallest
1.
2.
3.
4.
5.
6.
7.
8.
9.
Chromosome
Gene
Allele
Organism
Nucleus
Protein
Cell
Nucleotide
Genome
Biggest
Put these terms in size order & give an
example!!!
Biggest
1.
2.
3.
4.
5.
6.
7.
8.
9.
Organism
Cell
Nucleus
Genome
Chromosome
Protein
Gene
Allele
Nucleotide
- Human
- Red blood cell (RBC)
- Control centre
- Human genome
- Sex ones
- Collagen
- Collagen gene
- Blue eye
– G-A-T-C
Smallest
What makes you YOU?
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Mr A Lovat
17
http://www.bbc.co.uk/news/ukengland-coventry-warwickshire19463057
DNA Fingerprints
• DNA can be analysed to
make a unique pattern
• This pattern is unique and
can be used to identify you
How can you tell who’s saliva sample this is?
Looking at DNA:
Fruit DNA Extraction
DNA: A double-helix found in the
nucleus of every cell of your body
• Lets take a closer look!?
First image of
double-helix…
ever!
DNA from Fruit
Steps
1.
2.
3.
4.
5.
6.
7.
8.
Place a strawberry in a Ziploc bag and ensure it is sealed.
Grind it up with your fingers DONTY SPLIT THE BAG!
Add 10ML of extraction buffer and reseal the bag. Knead the strawberry again to mix.
Assemble a filter funnel with cheesecloth (as a filter) over a test tube and pour in the mixture
Leave to drip through into the test tube
Once it has filtered through, pour in the cold ethanol very slowly into the tube and observe (make
sure the test tube is left completely still after the ethanol has been poured in.
Dip the loop/glass rod into the tube where the athanol comes into contact with the strawberry
extract your should be able to remove the DNA
The DNA should form a long white strand as you pull it out of the extract.
https://www.youtube.com/watch?v=NCu7T_1_WLoOutline
SpeedTest: http://www.purposegames.com/game/dna-base-structure-quiz
DNA – true or false?
5. Homozygote
22. Chromosome
73. Genetic
disease
Periodic
Table
30. Dominant
7. Recessive
3. Gamete
101. Phenotype
Genome
.
9. Heterozygote
33. Allele
11. Chromosomes
93. Genes
6. DNA
94. Variation
13. Genotype
32 . Deoxyribonucleic acid
303.Punnet square 0. Inheritance
51. Nucleus
23. Huntington’s
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Objectives
I should be able to…
3.15 describe a DNA molecule as two strands
coiled to form a double helix, the strands
being linked by a series of paired bases:
adenine (A) with thymine (T), and cytosine
(C) with guanine (G)
3.16 understand that genes exist in alternative
forms called alleles which give rise to
differences in inherited characteristics
What is DNA made
of?
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Mr A Lovat
29
DNA deoxyribonucleic acid
http://www.bbc.co.uk/schools/gcsebitesize/scien
• DNA is made up of four
different bases.
• A gene is made up of
hundreds of these
bases.
• Three bases make one
amino acid.
• Amino acids are
bonded together to
make proteins
• Mutations can change
the structure of the
protein.
DNA is made of Necleotides
3 components:
– Pentose sugar
(ribose in DNA)
– Phosphoric acid
– Organic base
Phosphate
(always contains nitrogen)
Stay the same
sugar
Pentose sugar
(5 Carbon atoms)
base
Changes
Contains
nitrogen &
carbon
5’
3 hydrogen bonds
A joins to T (2 hydrogen bonds)
C joins to G (3 hydrogen bonds)
3’
C
G
0.34nm
Complementary Base Pairing
A
T
3’
2 hydrogen bonds
5’
2nm
The Double Helix
http://www.nobelprize.org/educational/medicine/dn
a_double_helix/dnahelix.html
http://learn.genetics.utah.edu/conte
nt/begin/dna/builddna/
Speed test!
• http://www.purposegames.com/game/dnabase-structure-quiz
For the DNA strand 5'-TACGATCATAT-3' the
correct complementary DNA strand is:
A
3'-TACGATCATAT-5'
B
3'-ATGCTAGTATA-5'
C
3'-AUGCUAGUAUA-5'
D
3'-GCATATACGCG-5'
E
3'-TATACTAGCAT-5'
Tell me…
4
3
names of bases in DNA…
Words that DNA stands for…
2
1
sets of bases that bond together…
gene codes for one…
Did you know,
the DNA in each
of your cells is
10-15mm long!?
Speed test!
• SpeedTest:
http://www.purposegames.com/game/dnabase-structure-quiz
Build a DNA
molecule
TASK
1. Use the sweets to build DNA
Things to show:
1.
2.
3.
4.
Double helix (coiling ladder) (Grade C)
Represent complementary base pairing (Grade B)
Sugar and phosphate backbone (A)
Without eating the sweets (A*)
Mount your DNA on A3 paper and label the parts
DO NOT EAT
THE SWEETS
TILL I SAY SO!
How do they look?
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A better one….
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Mr A Lovat
43
Clone a cat
• http://nature.ca/genome/04/041/0415_e.cfm
Wonderwall
or
SPLAT
5. Homozygote
22. Cystic fibrosis
73. Genetic
disease
Periodic
Table
30. Dominant
7. Recessive
3. Gamete
101. Phenotype
.
9. Heterozygote
33. Allele
11. Chromosomes
93. Genes
94. Variation
13. Genotype
6. DNA
303.Punnet square 0. Inheritance
51. Nucleus
23. Huntington’s
Objectives
I should be able to…
. 3.18 describe patterns of monohybrid
inheritance using a genetic diagram
. 3.20 predict probabilities of outcomes
from monohybrid crosses
Genetic jargon revision test
What do these genetic terms mean?
gene
Section of DNA that codes for a particular trait or
characteristic.
allele
A different form of a gene that codes for a
different version of a characteristic.
genotype
A description of the pair of alleles present for a
characteristic.
phenotype
The physical expression of the alleles.
What do these genetic terms mean?
homozygous
Pair of alleles that produce a characteristic
that are the same, e.g. HH.
heterozygous
Pair of alleles that produce a characteristic that
are different, e.g. Hh.
dominant
An allele that will always be expressed even when
there is only one of these alleles present,
represented by a capital letter.
recessive
An allele that will only be expressed when both
alleles are of this type, represented by a lower
case letter.
• Gregor Mendel was born in 1822 in
Czechoslovakia.
• Mendel came from a very poor family
and he decided to become a monk to get
the education he desired.
• Mendel
worked in the
monastery
gardens and
he became
fascinated
with how peas
grew.
• Mendel carried out research into how
characteristics were passed on in pea plants.
• He kept detailed records of all his findings.
• He came to the
conclusion that
some
characteristics
were dominant
over others and
they were never
mixed.
• He published a book
of his findings in
1866, when he was
44 years old.
• People did not
understand his
theories as no one
had seen
chromosomes.
• He died 20 years later
with no one taking
notice of his work.
• 16 years after his death people could
finally see chromosomes through a
microscope and he was given the
recognition for his findings.
Online Mendel (homework)
• Task:
• http://www2.edc.org/weblabs/Mendel/mend
el.html
• Instructions:
• Lesson 9 - Mendels Experiments
Instructions.pdf
http://www.youtube.com/watch?fea
ture=player_embedded&v=NWqgZU
nJdAY
• Wordwall inheritance key words
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Mr A Lovat
60
Genotype
Recessive
Chromosome
Allele
Phenotype
Gametes
Gene
Homozygous
Heterozygous
DNA
Genotype
Chromosome
Phenotype
Gene
Heterozygous
Alternative
forms of a gene
Sex Cell – egg
(Ovum) or Sperm
Strands of DNA
Physical
appearance of a
gene
Sections of DNA
(chromosome) that
determine inherited
characteristics
Recessive
Genetic make up
of an individual
Allele
The two alleles
present are
different
Gametes
The two alleles
present are the
same
Homozygous
DNA
DeoxyriboNucleic
Acid
The characteristics of
this allele will only be
seen if there is no
dominant gene present
Objectives
I should be able to…
. 3.18 describe patterns of monohybrid
inheritance using a genetic diagram
. 3.20 predict probabilities of outcomes
from monohybrid crosses
Task 1: Use the table below to match each of the keywords in the
word bank to its definition (grade D/C)
Word bank:
Phenotype ; Dominant ;Genotype ; Recessive ; Allele
Keyword
Definition
Different versions of the same gene.
Your physical appearance.
The combination of alleles you have for a
gene.
Task 2: Read the information about John and Carl then answer
the questions below:
Describe Carl’s phenotype (grade C)
___________________________________________________
_________________________________________
What is Carl’s genotype (grade B)?
______________________________________________
An allele that is always expressed even if you
only have one copy of it.
An allele that is only expressed if you have
two copies of it.
John
Carl
What could John’s genotype be (grade B)?
___________________________________________________
_________________________________________
Why can we not be sure exactly what Carls genotype is?
(Grade B/A)
___________________________________________________
Like all human beings, John and Carl each have two copies of the
gene that controls whether or not they have dimples.
The version of the gene (allele) that causes dimples is dominant. It
has the letter “D”.
The allele that causes you to not have dimples is recessive. It has
the letter “d”.
_________________________________________
___________________________________________________
_________________________________________
Characteristic Possible Alleles
Skin colour
Red- Dominant (R)
Blue -Recessive (r)
Spikes
Yes- Dominant (S)
No -Recessive (s)
Tail
Short- Dominant (T)
Long -Recessive (t)
Fire breathing Yes- Dominant (F)
No -Recessive (f)
Monster design:
Your monsters Genotype Your monsters Phenotype
(its combination of
(what the monster looks like)
alleles)
What characteristic will my monster pass on?
Parents Genotypes:
Alleles in sex cells:
Possible genotypes of
offspring:
• http://news.bbc.co.uk/1/hi/uk/7569064.stm
Harry
Potter
Genetics
Revision of key words 1
Different forms of
the same gene are
called alleles
Each gene controls a different
feature (e.g. eye colour)
We have 23 pairs
(or 46 single)
chromosomes.
Chromosomes are
found in the
nucleus
Chromosomes are
found in pairs in
most
mostcells…
cells
A gene is a short
section of the
chromosome
…except for the sex
cells (egg and
sperm)
Revision of key words 2
• For each characteristic, a child inherits one
allele from the mother and one allele from the
father.
• This means that we have two alleles for every
characteristic (e.g. eye colour).
• The alleles in a pair can be the same as each
other or different.
• Alleles can be dominant or recessive.
Revision of key words 3
B = brown eye allele
b = blue eye allele
• 2 dominant alleles
BB
• 2 recessive alleles
bb
There are only dominant brown
eye alleles so the child will have
brown eyes.
There are only recessive blue eye
alleles so the child will have blue
eyes.
• 1 dominant and 1 recessive allele
Bb
The dominant brown eye allele
‘wins’ so the child will have
brown eyes.
Discussion Task:
Is the ‘magical allele’ dominant or recessive?
Discuss the following information with your partner and use it to
decide whether the ‘magical allele’ is dominant or recessive.
• Harry’s parents were both wizards.
• Ron’s parents are both magical – and all
of his brothers and sisters are witches and
wizards too.
• Both of Hermione’s parents are Muggles
but she has still inherited magical abilities.
Remember:
Harry’s mum’s family
• The ‘magical’ (m) allele is RECESSIVE
• The ‘muggle’ (M) allele is DOMINANT
Mm
M
Mm
Harry’s grandparents
m
M
MM
Aunt Petunia
Mm
mM
Muggle
Muggle
Muggle
Your task:
m
Harry’s mum
mm
MAGIC
So, what was the % chance of Harry’s mum being magic?
Remember: The Dursley family
Aunt Petunia• The ‘magic’ (m) allele is RECESSIVE
• The ‘muggle’ (M) allele is DOMINANT
Uncle
Vernon
MM
Mm
M
Your task:
m
M
M
Cousin Dudley
MM
MM
mM
mM
Muggle
Muggle
Muggle
Muggle
So, what was the % chance of Dudley being magic?
The Weasley family
Mr Weasley
Bill
m
Charlie
Weasley
Mrs Weasley
mm
mm
Weasley
Your task:
m
m
Percy Weasley
mm
mm
MAGIC
MAGIC
Fred and
George
Weasley
m
Ron Weasley Ginny Weasley
mm
mm
MAGIC
MAGIC
What was the % chance of the Weasley children being magic?
Muggle-born witches and wizards
Hermione’s mum
and dad are both
Muggles…
(Some people question how
Muggles are able to produce
magical children. It is likely that
they would have a magical
ancestor, possibly several
generations ago.)
…but Hermione
is a witch.
What combination of alleles must
Mr and Mrs Granger have?
Is it possible for a child with one
magical parent and one Muggle
parent to be born with magical
abilities?
(Voldemort (Tom Riddle) was a half-blood
as his father, another Tom Riddle (snr)
was a Muggle and his mother was pureblood.)
Squibs
A Squib is a child born to
magical parents but who has
no magical ability.
(It is often considered
embarrassing to have a
Squib in the family.)
So how come Argus Filch is a Squib even though
both of his parents are magic?
Your task:
One way of drawing genetic cross
diagrams…
Another way of drawing genetic
cross diagrams… Punnet squ...
• Choose 2 examples of Harry Potter genetics.
• Draw a genetic cross diagram for each one.
• Next to each diagram, give the % chance of a child
being a witch or wizard in that family.
1. Mm and Mm (The Grangers or Harry’s mum’s family)
2. mm and mm (The Weasleys)
3. MM and Mm (The Dursleys)
4. MM and mm
5. Mm and mm (Voldemort’s family)
Slide 5
Slide 7
Slide 6
Extension task:
Your task:
• Write a paragraph to explain how witches and wizards
can be born of Muggle parents.
• Add another paragraph to explain why it is very rare for
Squibs to be born into wizarding families.
• Mr and Mrs Weasley have had 6 boys and 1 girl. If
they had another child, what would be the % chance of
it being a girl? Draw a genetic cross diagram to help you
explain. (Girl = XX. Boy = XY)
Your task:
One way of drawing genetic cross diagrams…
Mother’s alleles
Father’s alleles
Mm
Mm
M
MM
m
Mm
M
mM
m
mm
Another way of drawing genetic cross diagrams…
Punnet squares
Another way of drawing genetic cross diagrams…
Punnet squares
Another way of drawing genetic cross diagrams…
Punnet squares
Mother’s alleles
→
M
m
Another way of drawing genetic cross diagrams…
Punnet squares
Mother’s alleles
Father’s alleles
M
m
→
↓
M
m
Another way of drawing genetic cross diagrams…
Punnet squares
Mother’s alleles
→
M
m
M
MM
Mm
m
mM
mm
Father’s alleles
↓
Your task:
Another way of drawing genetic cross diagrams…
Punnet squares
Mother’s alleles
→
M
m
M
MM
Mm
m
mM
mm
Father’s alleles
↓
Objectives
• 3.21 understand that the sex of a person is
controlled by one pair of chromosomes, XX in
a female and XY in a male
• 3.22 describe the determination of the sex of
offspring at fertilisation, using a genetic
diagram
Numbers 1 - 8
• Listen to the following song and write down
the sex chromosomes found in the chorus.
• http://www.youtube.com/watch?v=ATWnHyb6-o
• Deaf screening:
http://news.bbc.co.uk/player/nol/newsid_728
0000/newsid_7287400/7287444.stm?bw=bb
&mp=wm&asb=1&news=1&bbcws=1
• Sex screening:
http://news.bbc.co.uk/1/hi/uk/7696696.stm
• Do you think IVF embryos should be screened
for deafness? Explain your answer considering
ethical, social and economic factors.
• Would it make a difference to your answer if it
was screening for cancer risk? Gender?
Criminality risk? Eye colour?