Chromosomes in meiocytes of butterflies are:
380
Understanding Chromosome Number in Butterfly Meiocytes
The question asks about the number of chromosomes found in the meiocytes of butterflies. A meiocyte is a cell that is destined to undergo meiosis, the process of cell division that produces gametes (like sperm and egg cells) or spores. Meiosis reduces the chromosome number by half compared to the somatic (body) cells of an organism. Therefore, the meiocyte contains the diploid number of chromosomes, which is the full set of chromosomes present in somatic cells.
What are Meiocytes?
Meiocytes are specialized cells in diploid organisms that undergo meiosis. In animals, these are typically germ line cells that produce sperm or eggs. Understanding the chromosome number in meiocytes tells us the diploid number ($2n$) for that species. The gametes produced after meiosis will have the haploid number ($n$).
Chromosome Count in Butterflies
Chromosome numbers vary significantly across different species of animals and plants. Butterflies (order Lepidoptera) exhibit a wide range of chromosome numbers, but many species have a relatively high number compared to other insects.
Based on biological studies and cytogenetic data, the diploid chromosome number ($2n$) in the meiocytes of certain common butterfly species is known to be significantly high.
Analyzing the Options
Let's look at the given options for the number of chromosomes in butterfly meiocytes:
- 200
- 208
- 308
- 380
These numbers represent the diploid count ($2n$) found within the meiocyte before it undergoes meiosis.
Among the provided options, the number that accurately reflects the chromosome count in the meiocytes of several butterfly species is 380. This means the diploid number ($2n$) is 380, and the haploid number ($n$) in their gametes would be $380/2 = 190$.
Conclusion on Butterfly Chromosomes
The number of chromosomes in the meiocytes of butterflies, representing their diploid state, is a characteristic feature of the species. While there is variation, 380 is a known chromosome number for some butterfly species, making it the correct choice among the options provided.
| Cell Type | Chromosome Number | Meiosis Involved? |
|---|---|---|
| Somatic Cell | Diploid ($2n$) | No (Mitosis for growth/repair) |
| Meiocyte | Diploid ($2n$) | Yes (Undergoes Meiosis) |
| Gamete (Sperm/Egg) | Haploid ($n$) | Produced by Meiosis |
Revision Table: Butterfly Chromosomes
| Term | Definition | Relevance to Question |
|---|---|---|
| Chromosome | Structures carrying genetic information (DNA). | Counted in meiocytes. |
| Meiocyte | Cell undergoing meiosis. | Contains the diploid ($2n$) chromosome number. |
| Diploid ($2n$) | Having two sets of chromosomes. | Chromosome number in meiocytes and somatic cells. |
| Haploid ($n$) | Having one set of chromosomes. | Chromosome number in gametes. |
| Meiosis | Cell division reducing chromosome number by half. | Process meiocytes undergo. |
Additional Information: Chromosome Numbers
Chromosome numbers are highly variable across the tree of life. For example, humans have 46 chromosomes ($2n=46$) in their somatic cells and meiocytes (47 in meiocytes just before meiosis I after replication, but the count is based on centromeres as 23 pairs of homologous chromosomes). The fruit fly, Drosophila melanogaster, has only 8 chromosomes ($2n=8$). Some ferns can have over 1000 chromosomes. This variability highlights the diversity of genetic organization in different organisms. The exact number of chromosomes is often species-specific and consistent within that species under normal conditions.
Important Questions from Heredity and Variation
Down’s syndrome is caused by:
The probability of having a haemophilia carrier daughter by a haemophilia carrier mother and a normal father is:
Which of the following statements are correct about Thalassemia?
A. In β-Thalassemia, production of β-globin chain is affected, and in α-Thalassemia, production of α-globin chain is affected.
B. α-Thalassemia is controlled by two closely linked genes HBA1 and HBA2.
C. The genes HBA1 and HBA2 are located on chromosome 11 of each parent.
D. β-Thalassemia is controlled by a single gene HBB.
Choose the correct answer from the options given below:
Match List-I with List-II:
List-I List-II (A) Phenylketonuria (I) Incomplete dominance (B) Haemophilia (II) 9:3:3:1 (C) Snapdragon (III) Pleiotropy (D) Dihybrid cross (IV) Sex-linked Choose the correct answer from the options given below:
The karyotype in Klinefelter’s syndrome is:
