In an Organism Such as a Sea Urchin, Administration of Actinomycin

question 15

Multiple Choice

In an organism such as a sea urchin, administration of actinomycin D prevents RNA synthesis. However, early development up to gastrula formation can take place in the presence of actinomycin D but gastrulation cannot. This implies that __________.

• A)development beyond gastrulation requires actD
• B)actD is part of the normal environment of a sea urchin and serves as a developmental signal molecule
• C)actD receptors begin to form only on cell surfaces of the gastrula
• D)maternal effect genes regulate development until gastrulation
• E)immature sea urchin embryos produce actD to regulate further development

---

Definitions:

Spine Fractures

Breaks in the bones of the spine, often caused by trauma, osteoporosis, or diseases, which can lead to pain and potentially serious complications.

Immunological Theory

A theory of aging that holds that the immune system is preset to decline by an internal biological clock.

Cellular Damage

Refers to injury to cells due to external factors like pathogens, toxins, or internal factors such as genetic mutations, leading to impaired cell function or death.

Aging

The process of becoming older, a physiological and biological progression that involves changes in physical, psychological, and social attributes over time.