1. Genetics
Adam Cleaver

2. Cell division
DNA
Genes
Chromosomes
DNA (deoxyribose nucleic acid) molecules are large and complex.
DNA (deoxyribose nucleic acid) molecules are large and complex.
They carry the genetic code that determines the characteristics of aaliving thing.
They carry the genetic code that determines the characteristics of living thing.
Genes - -A gene is aashort section of DNA. Each gene codes for aaspecific protein
Genes A gene is short section of DNA. Each gene codes for specific protein
by specifying the order in which amino acids must be joined together.
by specifying the order in which amino acids must be joined together.
Chromosomes - -The cell’s nucleus contains chromosomes made from long DNA
Chromosomes The cell’s nucleus contains chromosomes made from long DNA
molecules.
molecules.

3. Cell division - Mitosis
1
Mitosis produces two new
Mitosis produces two new
cells that are identical to
cells that are identical to 2
each other, and to the
each other, and to the
3
parent cell.
parent cell.
1) Parent cell.
1) Parent cell. 4
2) Chromosomes make identical copies of
2) Chromosomes make identical copies of
themselves.
themselves.
3) They line up along the centre.
3) They line up along the centre.
4) They move apart.
4) They move apart.
5) Two daughter cells form with identical
5) Two daughter cells form with identical
chromosomes to the parent cell.
chromosomes to the parent cell. 5
Mitosis is Asexual reproduction

4. Interphase
Prophase
Metaphase
Anaphase
Telophase
Cytokinesis - 2 identical cells formed

5. Mitosis mini plenary
Q4: How many times does the nucleus divide during mitosis?
Q3: At whatproduces cells that are......
Q1: Mitosis stage is this image?
Q2: What happens during Anaphase?
A) They line up across the middle of the cell
A) They line up across the middle of the cell
B) They start to move to opposite poles
B) They start to move to opposite poles
Q:5 How many gametes does mitosis produce?
C) The chromatids pair up to form chromosome
C) The chromatids pair up to form chromosome

6. Cell division – Sexual reproduction
Gametes
Gametes
Gametes & Gametes are sex cells. The male gametes are the
Gametes are sex cells. The male gametes are the
sperm, and the female gametes are the eggs.
sperm, and the female gametes are the eggs.
Fertilisation
Gametes contain one set of genetic information,
Gametes contain one set of genetic information,
while body cells contain two sets of genetic
while body cells contain two sets of genetic
information.
information.
Fertilisation
Fertilisation Gender
Gender
Fertilisation is the joining or fusion of aamale
Fertilisation is the joining or fusion of male Human body cells have 23 pairs of
Human body cells have 23 pairs of
gamete and aafemale gamete. The new cell
gamete and female gamete. The new cell chromosomes in the nucleus. One of
chromosomes in the nucleus. One of
that is formed divides over and over again by
that is formed divides over and over again by these pairs controls the inheritance of
these pairs controls the inheritance of
mitosis. This creates the many cells that
mitosis. This creates the many cells that gender - -whether offspring are male
gender whether offspring are male
eventually form aanew individual.
eventually form new individual. or female:
or female:
In males, the two sex chromosomes are different.
They are XY.
In females, the two sex chromosomes are the
same. They are XX

7. Sexual reproduction

8. Cell division - Sexual reproduction - Meiosis
Gametes are formed from cells in the reproductive
Gametes are formed from cells in the reproductive
organs by aatype of cell division called meiosis
organs by type of cell division called meiosis
The cells that are formed by meiosis have half as
The cells that are formed by meiosis have half as
many chromosomes as the cell that formed them.
many chromosomes as the cell that formed them.
Human body cells contain 23 pairs (46) of
Human body cells contain 23 pairs (46) of
chromosomes, while human gametes contain 23
chromosomes, while human gametes contain 23
single chromosomes.
single chromosomes.
The main features of meiosis are:
The main features of meiosis are:
the chromosomes are copied
the chromosomes are copied
the cell divides twice, forming four gametes
the cell divides twice, forming four gametes

9. Meiosis
MAKE KEY NOTES ON
VIDEO!!
Video to show the process of meiosis:

10. A slightly clearer clip on meiosis as the one in lesson may not
have been very clear

11. Meiosis mini plenary
Meiosis mini plenary
1) How many chromosomes are in the body?
2) Meiosis involves how many divisions of the nucleus?
3) Which of the following are examples of gametes?
Testes
Eggs
Sperm
Ovaries
4)How many gametes are produced by meiosis?

12. Inheritance

13. Inheritance
Inheritance
The resemblance of children to their parents is
The resemblance of children to their parents is
the result of genetic information passed on in
the result of genetic information passed on in
gametes (sex cells).
gametes (sex cells).

14. Your set of books has about 25000
chapters
Chapter 451 Chapter 451
Instructions Instructions
for blue eyes: for blue eyes:
Lorem ipsum dolor sit amet, consectetur Lorem ipsum dolor sit amet, consectetur
adipisicing elit, sed do eiusmod tempor adipisicing elit, sed do eiusmod tempor
incididunt ut labore et dolore magna incididunt ut labore et dolore magna
aliqua. Ut enim ad minim veniam, quis aliqua. Ut enim ad minim veniam, quis
nostrud exercitation ullamco laboris nisi nostrud exercitation ullamco laboris nisi
ut aliquip ex ea commodo consequat. ut aliquip ex ea commodo consequat.
Duis aute irure dolor in reprehenderit in Duis aute irure dolor in reprehenderit in
voluptate velit esse cillum dolore eu voluptate velit esse cillum dolore eu
fugiat nulla pariatur. Excepteur sint fugiat nulla pariatur. Excepteur sint
Set 1, Book 17, chapter 451 Set 2 Book 17, chapter 451
(from mother) (from father)
If each book is aachromosome, then each chapter is aagene, consisting of aaset of
If each book is chromosome, then each chapter is gene, consisting of set of
instructions for an aspect of the organism. .--The person in this example will have
instructions for an aspect of the organism The person in this example will have
blue eyes.
blue eyes.

15. Chapter 451
Instructions
Chapter 451
for blue eyes: Instructions
Lorem ipsum dolor sit amet, consectetur
adipisicing elit, sed do eiusmod tempor
incididunt ut labore et dolore magna
for brown
aliqua. Ut enim ad minim veniam, quis
nostrud exercitation ullamco laboris nisi
ut aliquip ex ea commodo consequat.
eyes:
Lorem ipsum dolor sit amet, consectetur
Duis aute irure dolor in reprehenderit in adipisicing elit, sed do eiusmod tempor
voluptate velit esse cillum dolore eu incididunt ut labore et dolore magna aliqua.
fugiat nulla pariatur. Excepteur sint Ut enim ad minim veniam, quis nostrud
exercitation ullamco laboris nisi ut aliquip
ex ea commodo consequat. Duis aute irure
Set 1, Book 17, chapter 451 Set 2 Book 17, chapter 451
(from mother) (from father)
In this example, the two corresponding chapters are not in agreement. In some cases like this, the
In this example, the two corresponding chapters are not in agreement. In some cases like this, the
body compromises between the two sets of instructions with eye colour, one set of instructions is
body compromises between the two sets of instructions with eye colour, one set of instructions is
more dominant than others. With eye colour, brown eyes are dominant, so although this person
more dominant than others. With eye colour, brown eyes are dominant, so although this person
carries instructions for both brown and blue eyes, the blue eye instructions are overridden and the
carries instructions for both brown and blue eyes, the blue eye instructions are overridden and the
person has brown eyes.
person has brown eyes.

16. Chapter 451 Chapter 451 Chapter 451 Chapter 451
Instructions Instructions Instructions Instructions
for blue eyes: for brown for blue eyes: for brown
eyes: eyes:
My mother My father
Chapter 451 Chapter 451
Instructions Instructions
for blue eyes: for blue eyes:
Me
SEE?
There is aa25% chance of this happening, and aa75%
There is 25% chance of this happening, and 75%
chance of having aabrown-eyed child.
chance of having brown-eyed child.

17. Alleles
Out there in the human population there are many versions of each chapter (gene). These versions
Out there in the human population there are many versions of each chapter (gene). These versions
are called alleles. In the case of eye colour, there is aablue version, aabrown, green, etc. For blood
are called alleles. In the case of eye colour, there is blue version, brown, green, etc. For blood
type there are three: A, BBand O. For some chapters (genes) there are hundreds of versions (alleles)
type there are three: A, and O. For some chapters (genes) there are hundreds of versions (alleles)
out there in the human population.
out there in the human population.

18. Alleles
Alleles are dominant or recessive:
Alleles are dominant or recessive:
the characteristic controlled by aadominant allele develops ififthe allele is present on one or both
the characteristic controlled by dominant allele develops the allele is present on one or both
chromosomes in aapair
chromosomes in pair
the characteristic controlled by aarecessive allele develops only ififthe allele is present on both
the characteristic controlled by recessive allele develops only the allele is present on both
chromosomes in aapair
chromosomes in pair

19. Where are the ‘books’ kept?
We now start to look closely at cells, to see where the ‘books’ (chromosomes) are kept.
We now start to look closely at cells, to see where the ‘books’ (chromosomes) are kept.
Every single cell contains aaset, within the nucleus (with aafew exceptions, such as red blood
Every single cell contains set, within the nucleus (with few exceptions, such as red blood
cells, which have no nucleus).
cells, which have no nucleus).
Here are some human cheek cells in which you can see the nuclei.
Here are some human cheek cells in which you can see the nuclei.

20. Mendel – genetic inheritance
Gregor Mendel (1822-1884) studied the inheritance
Gregor Mendel (1822-1884) studied the inheritance
of different characteristics in pea plants. He found
of different characteristics in pea plants. He found
that when he bred red-flowered plants with white-
that when he bred red-flowered plants with white-
flowered plants, all the offspring produced red
flowered plants, all the offspring produced red
flowers.
flowers.
If he bred these offspring plants (g1) with each
If he bred these offspring plants (g1) with each
other, most of the offspring (g2) had red flowers, but
other, most of the offspring (g2) had red flowers, but
some had white. This was because the allele for red
some had white. This was because the allele for red
flowers is dominant, and the allele for white flowers
flowers is dominant, and the allele for white flowers
is recessive. Genetic diagrams help to show how this
is recessive. Genetic diagrams help to show how this
works.
works. Original
parents
G1 = 1st generation of new offspring
G2 = 2nd generation
See family tree for further clarification.
The difference between the Simpson family tree G1
and the pea plants is that the original parent’s
offspring were mated together and Marge
obviously isn’t Abe and Mona’s daughter. – But
you get the idea! G2

21. Mendel – genetic diagrams
In aagenetic diagram, you show all of the possible alleles for aa
In genetic diagram, you show all of the possible alleles for
particular characteristic. There will be two alleles from one parent,
particular characteristic. There will be two alleles from one parent,
and two from the other parent, making four altogether. You then
and two from the other parent, making four altogether. You then
draw lines to show all the possible ways that these alleles could be
draw lines to show all the possible ways that these alleles could be
paired in the offspring. There will be four possible ways, but some or
paired in the offspring. There will be four possible ways, but some or
all of them could be repeated.
all of them could be repeated.
In genetic
diagrams, the
dominant allele is
shown as a capital
letter, while the
recessive allele is
G1 shown as a lower-
case letter.

22. G1
G2
Have a go with eye colour.
Parent one has Bb parent two has brown Bb

23. Can also be drawn as a punnett square
Can also be drawn as a punnett square
B b
B BB Bb
b Bb bb

24. Inheritance of disease – Huntinton’s
Huntington’s disease
Huntington’s disease
••Huntington’sdisease is an inherited disorder
Huntington’s disease is an inherited disorder
that affects the nervous system.
that affects the nervous system.
••Affectsmuscle coordination and leads to
Affects muscle coordination and leads to
cognitive decline and dementia.
cognitive decline and dementia.
••Itis caused by aadominant allele.
It is caused by dominant allele.
••Thismeans it can be passed on by just one
This means it can be passed on by just one
parent if they have the disorder.
parent if they have the disorder.

25. Cystic Fibrosis
Cystic fibrosis is an inherited disorder that
affects the cell membranes, causing the
production of thick and sticky mucus. It is
caused by a recessive allele. This means
that it must be inherited from both
parents.
Notice that the offspring with Ff are labelled 'carriers'. A carrier has one copy of the faulty allele, but
Notice that the offspring with Ff are labelled 'carriers'. A carrier has one copy of the faulty allele, but
does not have the disorder themselves. In this example above, both parents are carriers. They may
does not have the disorder themselves. In this example above, both parents are carriers. They may
not know they are, but there is aaone in four chance of them producing aachild who has cystic
not know they are, but there is one in four chance of them producing child who has cystic
fibrosis. It is possible to screen embryos to see ififthey carry alleles for genetic disorders.
fibrosis. It is possible to screen embryos to see they carry alleles for genetic disorders.

26. Cystic Fibrosis
In the example, one parent is aacarrier, while the
In the example, one parent is carrier, while the
other does not carry the allele for cystic fibrosis.
other does not carry the allele for cystic fibrosis.
They cannot produce aachild with the disorder, but
They cannot produce child with the disorder, but
they can produce children who are carriers.
they can produce children who are carriers.

27. Plenary
• Try to complete the
mini lesson test
• Fill out exit card
and return to me