How does a zygote differ from an ovum?

• A. A zygote is smaller.
• B. A zygote consists of more than one cell.
• C. A zygote is much larger.
• D. A zygote divides by meiosis.
• E. A zygote has more chromosomes.

Answer: (E)

Verified step by step guidance

1. Understand the definitions: An ovum is a mature female reproductive cell, which is haploid, meaning it contains a single set of chromosomes. A zygote is the result of the fusion of an ovum and a sperm cell, making it diploid, meaning it contains two sets of chromosomes.
2. Consider the chromosome number: An ovum has a haploid number of chromosomes (n), while a zygote has a diploid number (2n) because it is formed by the combination of the genetic material from both the ovum and the sperm.
3. Evaluate the options: The statement 'A zygote has more chromosomes' is correct because the zygote has twice the number of chromosomes compared to the ovum due to fertilization.
4. Clarify misconceptions: A zygote is not smaller than an ovum; it is typically the same size or slightly larger due to the addition of the sperm's genetic material. A zygote is a single cell initially, not more than one cell, and it divides by mitosis, not meiosis, to develop into an embryo.
5. Conclude with the correct understanding: The key difference in terms of chromosomes is that a zygote has more chromosomes than an ovum, as it is diploid compared to the haploid ovum.