Name Due Date Period. Biology SAC Lab. Biology I, MISD. Karyotype Cutout Lab

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1 Biology SAC Lab Biology I, MISD Objectives 2G) analyze, evaluate and predict trends from data 6B) recognize that components that make up the genetic code are common to all organisms 6H) describe how techniques such as chromosomal analysis are used to study the genomes of organisms Skills Arrange karyotypes from smallest to largest Find homologous chromosomes based on their banding Determine the sex of an individual based on their karyotype Identify chromosomal abnormalities on a karyotype Karyotype Cutout Lab Background: A karyotype is a photograph of the chromosomes in a eukaryotic cell s nucleus ( Karyo meaning nucleus). The chromosomes of a single cell undergoing mitosis are photographed and then arranged in pairs from largest to smallest with the sex chromosomes at the very end. Homologous chromosomes are ones that match in size, shape and banding (the stripes on the chromosome). For many decades, pictures of the chromosomes that make up a karyotype were cut and arranged by hand with scissors and glue. Now we have sophisticated technology that arranges karyotypes for us. Scientists and doctors use karyotypes to determine chromosomal abnormalities such as Down, Turner, Edward s, Patau, and Klinefelter Syndromes. Pre-Lab Assignment: 1. What are homologous chromosomes? 2. How can you tell if two chromosomes are homologs? 3. What chromosomes are abnormal in the following disorders? a. Down Syndrome: # b. Turner Syndrome: # c. Edward s Syndrome: # d. Patau Syndrome: # e. Klinefelter Syndrome: # Skills Applications Concepts pg. 1

2 Purpose: The purpose of this lab is to take a simulated photograph of a cell s chromosomes and arrange them from largest to smallest in their homologous pairs. You will also be able to determine the sex of the individual and identify, by name, any chromosomal disorders by their location on the karyotype. Materials: Scissors Glue Simulated photographed chromosomes (provided by the teacher) Safety: Be careful when using scissors- do not run with scissors, do not throw scissors, etc. Report any cuts immediately to teacher Procedure: 1. On the simulated chromosome photograph provided by your teacher, find the karyotype letter A, B, C or D. Circle the karyotype letter you have on the top of page Find the chromosome labeled 1 on your paper and carefully cut it out. Place the centromere of the chromosome (the middle) on the black line right above the number 1, leaving enough room for its homologous (matching) chromosome. Repeat steps 2-3 with all other pre-numbered chromosomes. Once all pre-numbered chromosomes have been glued down, pick an unnumbered chromosome that remains on your simulated photograph and carefully cut it out (try to start with the larger chromosomes first). Find the unnumbered chromosome s homolog and glue it down, centromere on the middle of the black line, neatly next to its homologous chromosome. Is it possible to have one set of 3 homologous chromosomes? 7. Repeat steps 5-6 until only the sex chromosomes remain (these will be the 1, 2 or 3 chromosomes that did not have a matching pair). Skills Applications Concepts pg. 2

3 8. Carefully cut out and glue the sex chromosomes above number Data: Answer the questions that correspond to the karyotype you just made. KARYOTYPE: A B C D (circle one) Skills Applications Concepts pg. 3

4 Analysis: 1. How many autosomes should a normal human karyotype have? 2. How many autosomes does this person have? 3. How many sex chromosoes should a normal human karyotype have? 4. How many sex chromosomes does this person have? 5. Based on the karyotype above, is this person male or female? 6. How do you know the sex of this person? 7. How many TOTAL chromosomes would a normal karyotype have? 8. How many TOTAL chromosomes does this person have? 9. Is this karyotype normal or abnormal? 10. On your karyotype, circle the abnormality. What number showed the abnormality? 11. What chromosomal disorder does this person have? 12. Explain how you can tell what chromosomal disorder this person has: 13. Is their disorder considered monosomy or trisomy? Why? Skills Applications Concepts pg. 4

5 TEACHER RESOURCES: All karyotypes for this lab have a disorder. The keys are as follows: Karyotype A: Down Syndrome (female) Karyotype B: Down Syndrome (male) Karyotype C: Klinefelter s Syndrome (male) Karyotype D: Turner s Syndrome (female) Skills Applications Concepts pg. 5

6 Karyotype A Skills Applications Concepts pg. 6

7 Karyotype B Skills Applications Concepts pg. 7

8 Karyotype C Skills Applications Concepts pg. 8

9 Karyotype D Skills Applications Concepts pg. 9