Explanation:
Let's go through each question step by step.
1. How many pairs of chromosomes are present?
- In a human karyotype, there are 23 pairs of chromosomes.
- This includes 22 pairs of autosomes and 1 pair of sex chromosomes.
- So, the answer is 23.
2. How many pairs of chromosomes are paired according to likeness?
- The chromosomes are arranged in pairs based on their size, shape, and banding patterns.
- All 23 pairs are matched this way.
- So, the answer is 23.
3. The sex chromosomes are placed on the last set. If the sex chromosomes are different, then it is a male. What is the sex of the individual?
- Look at the last pair of chromosomes (the sex chromosomes).
- In the image, the last pair shows one large chromosome and one small chromosome.
- This combination (one X and one Y) is typical for a male.
- So, the individual is male.
4. The diploid number of an organism is based on the total number of chromosomes, the haploid number is based on the number of pairs. What is the diploid number shown in the karyotype?
- The diploid number is the total number of chromosomes in a body cell.
- There are 23 pairs, and each pair has 2 chromosomes.
- So, 23 pairs × 2 = 46 chromosomes.
- The diploid number is 46.
5. How many autosome pairs are present?
- Autosomes are the chromosomes that are not sex chromosomes.
- There are 23 pairs total, and 1 pair is the sex chromosomes.
- So, 23 − 1 = 22 pairs of autosomes.
- The answer is 22.
6. In this situation, the individual would be diagnosed with Down Syndrome. This disorder causes physical and mental disabilities. Describe the underlying genetic cause of the disorder?
- Down Syndrome is caused by an extra copy of chromosome 21.
- Normally, a person has 2 copies of chromosome 21 (one from each parent).
- In Down Syndrome, there are 3 copies of chromosome 21.
- This is called trisomy 21.
- The extra chromosome causes the developmental and health issues seen in Down Syndrome.
7. (This is a follow-up to question 6, but no question is asked, so we don’t need to answer it.)
Final Answer:
1. 23
2. 23
3. Male
4. 46
5. 22
6. The genetic cause is trisomy 21, meaning there is an extra copy of chromosome 21.
Parent Tip: Review the logic above to help your child master the concept of karyotype worksheet answers.
