How is the animal hemisphere of a frog blastula different from the vegetal hemisphere?

• A. The cells of the vegetal hemisphere do not participate in gastrulation.
• B. The vegetal hemisphere is where the blastocoel is located.
• C. The cells of the vegetal hemisphere are pigmented more darkly than the cells of the animal hemisphere.
• D. The blastomeres in the animal hemisphere are larger than the cells in the vegetal hemisphere.
• E. The cells of the vegetal hemisphere have more yolk than the cells of the animal hemisphere.

Answer: (E)

Verified step by step guidance

1. Understand the structure of a frog blastula: A frog blastula is a spherical layer of cells (blastomeres) surrounding a fluid-filled cavity called the blastocoel. It is divided into two hemispheres: the animal hemisphere and the vegetal hemisphere.
2. Identify the characteristics of the animal hemisphere: The animal hemisphere is typically less yolk-laden, allowing for more rapid cell division. The cells here are smaller and more numerous compared to the vegetal hemisphere.
3. Identify the characteristics of the vegetal hemisphere: The vegetal hemisphere contains larger cells with more yolk. This yolk serves as a nutrient source for the developing embryo and slows down cell division.
4. Compare the pigmentation: The animal hemisphere is often more pigmented than the vegetal hemisphere, which is not a distinguishing factor in this context.
5. Conclude the main difference: The primary difference between the two hemispheres is the yolk content. The vegetal hemisphere has more yolk, which affects cell size and division rate, making it distinct from the animal hemisphere.