Karyotype Worksheet 1 | PDF | Karyotype | Cell Nucleus - Free Printable

Let’s go step by step through each question on the worksheet. We’ll use basic biology knowledge about chromosomes and karyotypes.

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Question 1: Look at the karyotype to the right (top right image)

a. Circle the Autosomal chromosomes
→ Autosomes are all chromosomes that are NOT sex chromosomes. In humans, these are pairs 1 through 22. So you would circle every pair from 1 to 22.

b. Put a box around the Sex chromosomes
→ The sex chromosomes are labeled X and Y (or XX/XY). In this karyotype, look at the bottom right — it shows “X” and “Y”. Box those two.

c. Is this person male or female?
→ If there is an X and a Y → MALE.
→ If there are two X’s → FEMALE.
Here, we see one X and one Y → MALE

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Question 2: How many total chromosomes does a normal person have?
→ Normal human cells have 46 chromosomes (23 pairs).
Circle: 46

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Question 3: Put a star on a homologous pair
→ Homologous pairs are matching chromosome pairs (same size, same genes). For example, both copies of chromosome 1 are homologous. Pick any numbered pair (like pair #1) and put a star on both chromosomes in that pair.

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Question 4: Look at the karyotype to the right (middle right image). Do you see any chromosomal abnormalities? YES / NO
→ Look carefully: There are three copies of chromosome 21 (instead of two). That’s abnormal.
Answer: YES

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Question 5: Put a circle around the abnormal chromosomes
→ Circle all three copies of chromosome 21.

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Question 6: Using the key below for chromosomal diseases, identify the disease this person has
→ Three copies of chromosome 21 = Trisomy 21 → Down’s Syndrome

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Question 7: Is this person male or female?
→ Look at the sex chromosomes at the bottom: It shows “XX” → FEMALE

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Question 8: Look at the karyotype to the left (bottom left image). Is it MALE or FEMALE?
→ At the bottom, we see “X” and “Y” → MALE

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Question 9: NORMAL or ABNORMAL?
→ Count the chromosomes: There are 47 instead of 46 (extra chromosome 21). Also, sex chromosomes are XY (normal for male), but extra autosome makes it abnormal.
Answer: ABNORMAL

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Question 10: Which chromosome is the longest and has the most genes? 1 or 21
→ Chromosome 1 is the largest. Chromosome 21 is one of the smallest.
Answer: 1

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Question 11: Which chromosome is the shortest and has the fewest genes? 2 or 22
→ Chromosome 22 is smaller than chromosome 2. Actually, chromosome 21 is even smaller than 22, but between 2 and 22, 22 is shorter.
Wait — let’s check standard knowledge:
Chromosome 21 is actually smaller than 22, but since 21 isn’t an option here, and 22 is smaller than 2 → Answer: 22

*(Note: In reality, chromosome 21 is smaller than 22, but since the question gives only 2 or 22, and 22 is smaller than 2, we pick 22.)*

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Question 12: In a normal karyotype how many autosomal chromosomes are there?
→ Total chromosomes = 46
Sex chromosomes = 2 (XX or XY)
Autosomes = 46 - 2 = 44

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Question 13: In a normal karyotype how many sex chromosomes are there?
→ Always 2 (either XX or XY)

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Question 14: One type of chromosomal mutation is trisomy 21. What is another name for it?
→ From the table: Trisomy 21 = Down’s Syndrome

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Final Answer:

1a. Circle chromosomes 1–22
1b. Box the X and Y chromosomes
1c. Male
2. 46
3. Star any matching pair (e.g., both chromosomes in pair #1)
4. YES
5. Circle all three chromosome 21s
6. Down’s Syndrome
7. Female
8. Male
9. Abnormal
10. 1
11. 22
12. 44
13. 2
14. Down’s Syndrome