Which one of the following combinations showing the chromosome numbers for human cells is CORRECT?
Show Hint
- Oogonium = 23, Fibroblast at G2/M = 92, Egg before fertilization = 23, Sperm = 23
- Oogonium = 46, Fibroblast at G2/M = 92, Egg before fertilization = 46, Sperm = 23
- Oogonium = 46, Fibroblast at G2/M = 46, Egg before fertilization = 46, Sperm = 23
- Oogonium = 46, Fibroblast at G2/M = 92, Egg before fertilization = 23, Sperm = 23
The Correct Option is B
Solution and Explanation
Step 1: Understanding chromosome numbers.
- The oogonium (female germ cell) starts with 46 chromosomes, which are reduced to 23 chromosomes during meiosis in the egg cell.
- Fibroblast cells at G2/M phase have 92 chromosomes (since they are diploid and the chromosomes are doubled during cell division).
- The sperm cell has 23 chromosomes, as it is a haploid gamete.
Step 2: Analyzing the options.
- (A) Oogonium = 23, Fibroblast at G2/M = 92, Egg before fertilization = 23, Sperm = 23: Incorrect. The oogonium should have 46 chromosomes, not 23.
- (B) Oogonium = 46, Fibroblast at G2/M = 92, Egg before fertilization = 46, Sperm = 23: Correct. The numbers of chromosomes match the typical human cell and gamete counts.
- (C) Oogonium = 46, Fibroblast at G2/M = 46, Egg before fertilization = 46, Sperm = 23: Incorrect. Fibroblast at G2/M phase should have 92 chromosomes, not 46.
- (D) Oogonium = 46, Fibroblast at G2/M = 92, Egg before fertilization = 23, Sperm = 23: Incorrect. The egg before fertilization should have 46 chromosomes.
Step 3: Conclusion.
The correct answer is (B) as it shows the correct number of chromosomes for each cell type.
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