Let’s Play!
All of these topics will be on your test tomorrow, so pay attention!

Meiosis: The
Steps
Meiosis
Vocabulary
Random chromosome segregation
& probability
Fertilization
Gender determination
How much
DNA?
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List the steps of meiosis in order

1. Prophase
2. Metaphase
3. Anaphase
4. Telophase
5. Cytokinesis
(this then repeats)

During which stage of meiosis does crossing over occur?

Prophase 1

How many cells are produced by the end of cytokinesis 2?

4

Homologous chromosomes are separated during this stage of meiosis

Anaphase 1

Sister chromatids are separated during this phase of meiosis.

Anaphase 2

After replication, these segments of
DNA look like the letter X

chromosome

Somatic cells are
2N, which indicates two sets of chromosomes.
What word means
2n?

diploid

Gametes are labeled N because they have one set of chromosomes.
What word means N?

Haploid

The left and right side of a chromosome when it looks like an X are called ______

Sister chromatids

The fusion of two gametes creates a diploid cell called a
______

zygote

The chance that a gamete will have the paternal homologue of a chromosome is
_____%

50

The chance that a gamete will have two paternal homologues is ___% (show your calculations)

½ x ½ = ¼
¼ = 25%

Set up and evaluate an expression to calculate the probability of a gamete having 5 paternal homologues

½ x ½ x ½ x ½ x ½
1/32

Draw all possible gametes that can be produced from the parent cell below
X X
X X
Note: this parent cell has already undergone DNA replication

What is the probability of an
Rh+/Rh- man producing a sperm cell with a Y chromosome and an
Rh+ gene?

1/8

Fertilization occurs when a sperm cell and an ovum combine to form one cell. Sperm and ova are both _____.

gametes

The name of the cell created by the fusion of a sperm cell and an ovum is a ______.

zygote

Not all of the cells created by females during meiosis are used during fertilization. What are these cells that are discarded and how many are made from one cell undergoing meiosis?

Polar bodies

After fertilization occurs, the zygote grows by creating more cells. What process produces these new cells?

meiosis

By mistake, an ovum has two copies of the 21 st chromosome. How many copies of the 21 st chromosome will the zygote have if the ovum is fertilized by a normal sperm?

3. This condition results in Down
Syndrome.

Women have ___ copies of the X chromosome while men have __.

2, 1

What sex chromosome do ova always contain?

X

Why do sperm determine the gender of the child?

Sperm can contain an X or a Y chromosome, which will pair with the X chromosome in the ovum.

What is the probability of a couple having two boys?

½ x ½ = ¼
Chance of boy 1
Chance of boy 2

What is the chance of a woman with A/B blood and a man with A/B blood having a boy with B/B blood?

1 x ½ x ½ x ½ = 1/8

Parent cells of meiosis have ___ copies of each chromosome. They are ____ (2N).

2, diploid

After DNA replication, chromosomes look like an X. The cell has __ times as much DNA as it started with.

2

Somatic cells have
___ times as many chromosomes as gametes.

2

If your somatic cells have
46 chromosomes, how many chromosomes do your gametes have?

23

You discover a new species. It has gametes with 27 chromosomes.
How many chromosomes do you expect to find in its somatic cells?

54

Name 3 key differences between mitosis and meiosis.
One of your differences must be a drawing of metaphase
1 in meiosis and metaphase in mitosis.

Mitosis
Produces 2 somatic cells
(diploid)
Daughter cells are identical
Meiosis
Produces 4 gametes
(haploid)
Daughter cells are different from eachother
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