Explain Chromosomal Abnormalities and Crossing Over for High School Biology

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In your high school biology class, do you want to explain how cells get chromosome genetic abnormalities like deletion, duplication, inversion, and translocation? Do you want your students to be active in their learning and discover for themselves how crossing over during meiosis can go wrong? This is the lesson for you!

It is hard to visually explain how chromosomal abnormalities are formed and crossing over is also difficult to visualize for students. I normally use this lesson at the end of a mitosis/meiosis unit, after my students understand what the product cells form meiosis normally are, what homologous chromosomes are, and what the chromosomal abnormalities are (deletion, duplication, inversion, translocation).

In this lesson, your students will use colored pencils to trace over chromosomes and chromosomes with crossing over between them to let them separate out the meiotic products. My students love this lesson because it is a lesson where they can see for themselves how to produce the chromosomal abnormalities that cause so many human genetic disorders.

In this packet, I include a way to differentiate this lesson. For pages 4 and 5, the Mistakes in Crossing Over pages, I include 2 options. You can print pages 4a and 5a, which are easier and have the students analyze the diagram. Or you can print pages 4b and 5b (really pages 6 and 7) which require the students to produce part of the diagram and analyze it. In my college prep/lower level classes, I use pages 4a and 5a. In my honors or AP, I use pages 4b and 5b.

Page 1: Meiosis 1 and 2 Products
Page 2: Single Crossovers
Page 3: Double Crossovers
Page 4: Mistakes in Crossing Over #1 (deletions, duplications, chromosomes without centromeres or with 2)
Page 5: Mistakes in Crossing Over #2 (inversions, translocations)
Page 6: Optional Harder Page 4b
Page 7: Optional Harder Page 5b.
Page 8: Teacher Instructions
Page 9: Terms of Use

I designed this lesson to address Next Generation Science Standard*
HS-LS3-2: Make and defend a claim based on evidence that inheritable genetic variations may result from: (1) new genetic combinations through meiosis, (2) viable errors occurring during replication, and/or (3) mutations caused by environmental factors.

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*Next Generation Science Standards is a registered trademark of Achieve. Neither Achieve nor the lead states and partners that developed the Next Generation Science Standards was involved in the production of, and does not endorse, this product. (Disclaimer written and required by Next Generation Science Standards for all lessons sold that reference their name)
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45 Minutes

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Explain Chromosomal Abnormalities and Crossing Over for Hi
Explain Chromosomal Abnormalities and Crossing Over for Hi
Explain Chromosomal Abnormalities and Crossing Over for Hi
Explain Chromosomal Abnormalities and Crossing Over for Hi