​Glue

​Glue

​Glue pages together as shown.

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​Then fold up so only the title 'Meiosis' is showing.

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​Write "Mitosis:" where shown.

Meiosis Foldable

Mitosis: the creation of somatic cells.

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Occurs by cell division that results in two identical daughter cells. Each has the same DNA and the same number of chromosomes as the parent cell.

Meiosis Foldable

Meiosis: the creation of gametes.

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Occurs by cell division that results in four daughter cells. Each has half the number of chromosomes of the parent cell.

Meiosis Foldable

Key Hints (no need to write):

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​Meiosis is just mitosis, but twice!

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Same steps occurring 2 times

So we have:

Meiosis I

&​

Meiosis II

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Order

I

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​​P

​M

​A

​T

​C

​Interphase occurs only once.

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​The other phases occur twice.

​x2

Interphase

“G1- before DNA replication”

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The cell grows & prepares for division

Interphase: S-phase - DNA Replication

The DNA must make a copy of itself so that each new cell gets the DNA it needs.

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In DNA replication A-T will pair together & C-G will pair together.

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​A student builds a model of a DNA strand.

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​Which of these models of a DNA strand shows bases that are complementary to the ones on the student's DNA model?

​C

​A

​G

​C

​C

​A

​T

​C

Interphase: S-phase - DNA Replication

The sides or the backbone of the DNA are made up of

__________ & ______.

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The 2 sides are held together with

____________ bonds connecting the matching nitrogenous _______ pairs.

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​Chromosomes

​Every somatic cell of a human has the exact same 23 pairs of chromosomes.

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One of these chromosomes came from your dad’s gamete and the other from your mom’s gamete.

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In S phase each individual chromosome will replicate, giving you 4 of each type of chromosome or a tetrad.

​Crossing Over

​Crossing over increases genetic variation and ensures all gametes are genetically different.

Prophase 1

DNA condenses into chromosomes

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Tetrads form with homologous chromosomes

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Crossing over occurs (exchange genetic material, increases genetic diversity)

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Metaphase 1

Chromosomes line up in the Middle of the cell

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Independent assortment increases genetic diversity.

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Anaphase 1

Chromosomes are pulled apart to opposite ends

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Telophase 1

Chromosomes unwind to form chromatin

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Nuclei form (Two nuclei)​

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Followed by Cytokinesis 1 (cell splits, cytoplasm divided in half)​

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Meiosis II - Prophase II

Two cells

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​DNA condenses to chromosomes

Metaphase II

Chromosomes line up in the Middle of the cell

Anaphase II

Chromosomes move to opposite ends of the cell

Telophase II

Chromosomes unwind back to chromatin

Nuclear membranes reform

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Cytokinesis II

Each cell splits, divides cytoplasm in half.

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Creates 4 haploid gamete cells.

Each has 23 chromosomes.

Each is genetically different.

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Modeling Meiosis with Clay​

Cell Cycle - Mitosis vs Meiosis

I

​

​

​​P

​M

​A

​T

​C

​1.Diploid number is always twice the haploid number.

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​2. Homologous chromosomes are chromosomes that code for the same traits, but come from different parents.

​For example, you have two chromosomes with the genes that code for your eye color. One chromosome with the eye color genes comes from your mom, and one chromosome with the eye color genes comes from your dad.

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​6. The gametes would have copies of the same chromosome instead of having different chromosomes. These gametes would be infertile.