• Describe how sex cells are formed
• State that, at fertilisation, gametes combine to form a diploid
• State that gametes are produced by meiosis.
• State that gametes are haploid
• State that meiosis introduces variation.
• Explain how the mitochondria and acrosome of a sperm cell
is adapted to its function
• Explain what happens to the chromosomes during meiosis
• What is the scientific
name for the human
• What are the male
and female sex cells?
• What is the name for
the moment in which
the sperm enters the
have a tail for swimming
have a nucleus to carry genes
produced in large numbers to
increase the chance of
are large to contain a food
Eggs and sperm
The female egg cell and the male sperm cell are examples of
The ______ cell is
specialised in two ways:
The egg cell is basically
an enlarged cell with
massive _____ reserves
Head packed with
______ its way
through the egg
Strong tail for
Words – food, swimming, sperm, specialised, digest
What is meiosis?
How does meiosis turn one cell into four new sex cells?
Each daughter cell has half
the number of chromosomes
of the parent.
Mitosis vs. Meiosis
Used for growth and repair of
2. Used in asexual reproduction
3. Cells with identical number of
chromosomes and genetic
information are produced
Used to produce gametes for
2. Each daughter cell has half the
number of chromosomes of the
Which type of cell division produces gametes?
What does meiosis introduce into the daughter cells that
mitosis does not?
Variation – difference in the chromosomes, or they are not
In humans, body cells contain two pairs of 23
chromosomes – 46 in total. What name do we give to a
cell that contains a pair of each chromosome?
Cells produced by meiosis have only one of each
chromosome. What name do we use to describe this type
Describe how a zygote forms.
Nucleus of egg joins with the nucleus of a sperm
Name as many differences as you can between
meiosis and mitosis.
Meiosis involves two different divisions. Describe what
happens to the chromosomes in each division and
explain how this changes the number of chromosomes
in the new cells.
First division – homologous pairs
separate; half go to one pole and the
other half to the other pole, which
reduces the number of
Second division – chromosomes
split as in mitosis
daughter cells not
two daughter cells
four daughter cells
diploid cells form
haploid cells form
homologous pairs do
homologous pairs meet
involves two divisions
body cells form
no crossing over