Denver System Worksheet Karyotype Answers 💎

| Abnormality | Karyotype formula | Worksheet observation | |-------------|------------------|------------------------| | Down syndrome | 47, XY, +21 | Three chromosomes in Group G, specifically extra #21 | | Turner syndrome | 45, X | Only one X, no Y, total 45 chromosomes | | Klinefelter syndrome | 47, XXY | Two X in Group C, one Y in Group G | | Edward syndrome | 47, XY, +18 | Extra chromosome in Group E (#18) | | Patau syndrome | 47, XY, +13 | Extra chromosome in Group D (#13) | | Cri-du-chat syndrome | 46, XX, del(5p) | Deletion of part of the p arm on one #5 chromosome (visible band missing) |

If your worksheet contains specific chromosome images or a unique abnormality, apply the same Denver System rules, and you will arrive at the correct interpretation. denver system worksheet karyotype answers

| Pair | Group | Centromere | Identifying features | |------|-------|------------|----------------------| | 1 | A | Metacentric | Largest, uniform bands | | 2 | A | Submetacentric | Slightly smaller than #1 | | 3 | A | Metacentric | Smaller than #2 | | 4 | B | Submetacentric | Large, dark bands on q arm | | 5 | B | Submetacentric | Lighter banding than #4 | | 6 | C | Submetacentric | Medium, X-like | | 7 | C | Submetacentric | Distinct central band | | ... | ... | ... | ... | | 21 | G | Acrocentric | Satellites on p arm | | 22 | G | Acrocentric | Smaller than #21, satellites | | X | C | Submetacentric | Matches #7 size | | Y | G | Acrocentric | No satellites, slightly larger than #22? (varies) | Mastering the Denver System is essential for any student of genetics, medicine, or laboratory science. When completing a karyotype worksheet, always follow the logical sequence: count → sex chromosomes → group by size → refine by centromere → confirm by banding → diagnose abnormalities . The system provides a universal language that has enabled countless discoveries in prenatal diagnosis, oncology, and evolutionary biology. | Abnormality | Karyotype formula | Worksheet observation

“The karyotype shows three copies of chromosome 21 in Group G, indicating trisomy 21 (Down syndrome).” Question 4: Why is chromosome 21 placed in Group G (the smallest group) instead of near chromosome 22? Answer: Although chromosome 21 is slightly larger than 22 historically, the Denver System orders primarily by size but groups acrocentric chromosomes together. Both 21 and 22 are acrocentric and very short, so they fall into Group G. The numbering (21 vs. 22) is a historical artifact based on earlier technology; under the microscope, they look similar in size and shape. Question 5: A karyotype shows a large submetacentric chromosome pair that does not match any in Group B. What might this indicate? Answer: This could indicate a translocation . For example, in Robertsonian translocation, the long arms of two acrocentric chromosomes (e.g., 14 and 21) fuse, creating one large submetacentric chromosome. This is common in balanced translocation carriers (45 chromosomes but normal phenotype) or in some cases of familial Down syndrome. Part 4: Sample Worksheet Answer Key (Short Form) If a worksheet provides a scrambled photomicrograph, the correct Denver System arrangement should be presented as: (varies) | Mastering the Denver System is essential