Name:
Ms. B
Date:
AP Bio
Lab # 3: Mitosis and Meiosis
PRE-LAB WRITE-UP
This pre-lab write up is to ensure that you understand the concepts behind the AP lab. Without this knowledge, you
will not be able to successfully complete the lab exercise. We will not have time to stop and explain the lab once we
have begun. To ensure understanding, you will complete the following assignment:
Visit the site: http://www.phschool.com/science/biology_place/labbench/
Complete the tutorials and exercises in order. Then, take the lab quiz at the end. After you click “check your
answers”, copy and paste the quiz into your document. This pre-lab is due the day the lab exercise is carried out.
Please note that some labs have multiple sections and more than one quiz. You are responsible for completing all
sections assigned.
Exercise 3B, Meiosis ONLY:

Briefly describe the stages of meiosis

What is crossing over? Synapsis?

What results indicate that crossing over occurred in the Sordaria?

In the analysis of results II section, answer the following questions:
o
In the photo, how many asci marked with an X show no evidence of crossing over?
o
In the photo, how many asci marked with an X show evidence of crossing over?
o
In the photo, what is the total number of asci marked with an X?
o
What is the percent of crossovers? (number of asci with crossovers divided by total number of asci
multiplied by 100)
o
For the sample shown here, what is the map distance between the gene for spore color and the
centromere? (percent of crossovers divided by 2)
Now, Read the actual lab! After you have completed the questions above, LabBench Tutorial, and Quiz, complete
the two questions below.
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1. Construct a flow-chart of events in this lab (beginning with exercise 3B: Meiosis, pg 35). This flow chart
should help you in the day of the assignment and guide you to complete the lab properly.
**This pre lab should be COMPLETED on your desk from the moment the bell rings on the day of the lab. Be sure
you are ready to go!
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